Funding for this work was provided by ORWH SCOR P50 DK064540, RO1 DK 051406, RO1 AI 108749-01, F32 DK 101171, and F32 DK 104516-01.

Ethics statement: The Washington University Animal Studies Committee approved all mouse infections and procedures as part of protocol number 20150226, which expires 12/10/2018. Overall care of the animals was consistent with The Guide for the Care and Use of Laboratory Animals from the National Research Council and the USDA Animal Care Resource Guide. Euthanasia procedures are consistent with the &#8220;AVMA guidelines for the Euthanasia of Animals 2013 edition.&#8221;
1. UPEC UTI Protocol, Inoculation Needle Preparation (Figure S1)
<ol>
	<li>Remove the cap of the 30 G needle. Thread approximately 1 inch of PE10 tubing onto the shaft of the needle. UV sterilize the needle assemblies overnight. Catheterized needles can be stored indefinitely in sterile petri plates.</li>
</ol>
2. UPEC Bacterial Inoculum Preparation
<ol>
	<li>Prepare UTI89 inoculum (start 72 hr prior to the inoculation day)
	<ol>
		<li>Streak UTI89 onto an LB (Luria-Bertani) agar plate from a frozen stock. Incubate overnight at 37 &#176;C. Pick a colony and inoculate it into 10 ml of LB in a 125 ml flask. Incubate at 37 &#176;C for 24 hr, statically.</li>
		<li>Inoculate 10 &#181;l of overnight culture into 10 ml of LB in a new 125 ml flask for an additional 24 hr at 37 &#176;C, statically.</li>
		<li>Transfer 3 ml (will vary based on strain and desired inoculum size) to sterile 1.5 ml tubes and centrifuge at 7,000 x g for 3 min and resuspend the pellet in 1x PBS and centrifuge a second time. Resuspend the bacterial pellet in 1 ml 1x PBS.</li>
	</ol>
	</li>
	<li>Measure bacterial optical density and adjust concentration to the desired inoculum density. The standard concentration of the inoculum used is 107 bacteria; however, this may vary due to the design of the study.</li>
</ol>
3. Bacterial Inoculation
<ol>
	<li>Clean the workstation with 70% ethanol and cover area with absorbent paper (or use sterile flow hood).</li>
	<li>Draw up to 0.9 ml of the prepared bacterial inoculum into a 1 ml (TB) syringe (remove air bubbles). Attach a prepared sterile inoculation needle with PE10 tubing, onto the syringe containing the inoculum, then sterilely trim the polyethylene tubing. 
	NOTE: Leave 1 mm of tubing above the tip of the needle to avoid puncturing the bladder.</li>
	<li>Cut a 1 inch square piece of parafilm and put a dab of surgical lubricant (approximately the size of a dime) on top.</li>
	<li>Anesthetize female C3H/HeN mice by putting them in a vaporizer chamber (following manufactures protocol) until unconscious but still breathing normally (1 breath/sec). 
	NOTE: Some IACUC committees do not approve the use of a vaporizer. Please follow the indication of the IACUC committee of your institution. 
	CAUTION: Isoflurane is an inhalation anesthetic. Use in a well-ventilated area and minimize inhalation.</li>
	<li>Remove the mouse from the vaporizer and place it on its back on a paper towel and spread the legs.</li>
	<li>Cover the nose of the mouse with a nose cone (a tube connected to the vaporizer that provides a controlled isoflurance dose that comes equipped on some vaporizer units) to maintain anesthetization.</li>
	<li>Gently palpitate the bladder to induce urination and ensure a voided bladder. Wipe the periurethral area with 100% ethanol wipe. Dab the inoculation needle/syringe, point first, into the surgical lubricant.</li>
	<li>Inoculate each mouse with 50 &#181;l of the bacteria solution by inserting the inoculation needle transurethrally, approximately 12 mm, and pressing down on the syringe plunger gently to dispense the inoculum into the bladder gently (10 &#181;l/sec). Remove the inoculation needle from the mouse. 
	NOTE: Immediate return of inoculum at the urethral opening when beginning to inoculate indicates improper or incomplete insertion of the needle.</li>
	<li>Remove the mouse from nose cone and return it to its cage. Repeat steps 3.3-3.8 for each mouse. When/if switching inoculum conditions/strains, dispose of the syringe and inoculation needle in an approved sharps container and start again step 3.2.&#160;&#160; 
	NOTE: Inoculation with uropathogenic organisms generally does not cause severe pain symptoms. However, in rare instances, administering large doses of pathogens may cause fever, reduction in food and water intake and abnormal behavior. Animal health should be monitored throughout the experiment. If overt pain symptoms are notice, an analgesic, such as Buprenorphine (0.05&#8722;0.1 mg/kg given subcutaneously), can be applied. Procedures should be in accordance with each institution&#8217;s IACUC.</li>
</ol>
4. Determination of Bacterial Burdens
<ol>
	<li>Prepare separate 5 ml tubes for each bladder and kidneys pair to be harvested. Add 1ml of 1x PBS/tube/mouse bladder to be harvested. Add 0.8 ml of 1x PBS/tube/pair of mouse kidneys to be harvested. Label each tube to correspond to a given mouse. Prepare a 96-well plate containing 180 &#181;l of 1x PBS in each well for 1:10 serial dilutions.</li>
	<li>Clean the work area with 70% ethanol and cover the area with an absorbent cover or paper towel.</li>
	<li>Anesthetize the mouse with isoflurane (see step&#160;3.4) until the mouse stops breathing for approximately 1 min, then place it on the absorbent cover or paper towel. Other methods of euthanasia are also accepted by IACUC committees, such as carbon dioxide, and can be substituted for isoflurane overdose.</li>
	<li>Sacrifice the mouse by rapid cervical dislocation that consists of restraining the neck at the base of the head and pulling the tail horizontally away from the body until dislocation occurs. 
	NOTE: Most IACUC committees require a secondary means of euthanasia and cervical dislocation is a common method. However, other methods can be used if approved by the IACUC committee.</li>
	<li>Place the dead mouse on its back and spray 70% ethanol on the abdomen. Dissect the mouse, harvest the bladder and kidneys, in that order to minimize potential contamination from the blood following the kidney dissection. Place the organs independently into the prepared 5 ml tubes containing 1x PBS (see step 4.1). 
	NOTE: Use different scissors for the external dissection and for organ harvesting to minimize contamination.</li>
	<li>Tap the tube to ensure the organs are in the 1x PBS. Repeat step 4.3-4.5 for each mouse. Clean scissors and forceps in 70% ethanol after each mouse.</li>
</ol>
5. Bacterial Recovery
<ol>
	<li>Homogenize harvested bladder and kidneys in the 5 ml tubes with a tissue homogenizer, 15 sec per kidney and 30 sec per bladder. Rinse homogenizer sequentially in 1x PBS, 70% ethanol and 1x PBS between samples.</li>
	<li>Make serial 1:10 dilutions out to 10-8 and plate each dilution for CFU (colony forming units) on LB agar plates. Incubate the plates at 37 &#176;C overnight and count colonies the next day.</li>
</ol>
6.&#160;IBC Enumeration
<ol>
	<li>Aseptically remove the bladder and place it in 1x PBS in a 6-well plate with a silicone bottom. Plates can be prepared using a silicone elastomer kit and pouring approximately 1 cm of silicone in each well, see manufactures instructions. Cut the bladder in half using scissors.</li>
	<li>Using small metal pins gently splay the bladder so that the bladder lumen is facing upward. Be sure to place the pins at the outermost edges of the bladder sections to ensure the maximal amount of urothelium is exposed.</li>
	<li>After splaying, gently wash the bladder once with 1x PBS. Remove the 1x PBS by pipet. Fix the bladder by adding enough 3% paraformaldehyde to cover the entire splayed bladder. CAUTION: Paraformaldehyde is carcinogenic. Proper protective equipment, including gloves, should be worn at all times. Disposal should follow institutional guidelines.</li>
	<li>Incubate at room temperature for 1 hr. Remove paraformaldehyde solution. Wash once with 1x PBS.</li>
	<li>Wash with LacZ wash solution (2 mM MgCl2, 0.01% sodium deoxycholate and 0.02% nonidet-p40in 1x PBS) three times for 5 min per wash.</li>
	<li>Remove wash solution and add enough LacZ stain (9.5 ml LacZ wash solution, 0.4 ml 25 mg/ml X-gal and 0.1 ml of 100 mM K-ferrOcyanide/K-ferrIcyanide) to cover the bladders. Incubate at 30 &#176;C overnight protected from light.</li>
	<li>Remove splayed bladders from incubator and observe IBCs, which appear as blue puncta as visualized with a dissecting scope, 40-60X magnification. 
	NOTE: Sometimes a mouse may urinate prior to placement of the tube under the urethra. In this case, wait 15-20 min before attempting to collect urine again.</li>
</ol>
7. Urine Collection for Bacteriuria CFU Enumeration (Not Applicable for CAUTI)
<ol>
	<li>To collect urine pre or post infection gently restrain the mouse by holding the tail and placing it on a flat elevated surface (top of mouse cage).</li>
	<li>Hold a sterile 1.5 ml tube under the mouse urethra. Gently press down on the back of the mouse near the tail to apply pressure to the bladder. Catch the urine in the 1.5 ml tube.</li>
	<li>Make serial 1:10 dilutions out to 10-7 and plate each dilution on appropriate LB. Incubate the plates at 37 &#176;C overnight and count colonies the next day.</li>
</ol>
8. CAUTI Model Protocol, Catheter Needle Preparation for CAUTI Model (Figure S2)
<ol>
	<li>Remove the cap of the 30 G needle. Cut a 7 mm piece of PE10 tubing and 5 mm piece of silicone tubing such as RenaSIL. Thread the needle with PE10 tubing until the tubing touches the base of the needle.</li>
	<li>Then feed the 5 mm piece onto the PE10-containing needle. UV sterilize the needles assemblies overnight. 
	NOTE: When loading the silicone tubing, leave approximately 1 mm of the tubing extending past the needle tip.</li>
</ol>
9. E. faecalis OG1RF Bacterial Inoculum Preparation
<ol>
	<li>Prepare OG1RF inoculum starting 48 hr prior to the inoculation day. Streak OG1RF onto a BHI (brain heart infusion) plate from a frozen stock.</li>
	<li>Pick a colony and inoculate it into 10 ml of BHI and grow it statically for 18 hr at 37 &#176;C. Centrifuge the culture and wash the pellet (3 times) in 1 ml volumes of sterile 1x PBS.</li>
	<li>Resuspend the bacterial pellet into 1x PBS. Measure bacterial optical density and adjust the concentration to the desired inoculum size. The standard concentration of the inoculum used is 107; however, this may vary due to the design of the study</li>
</ol>
10. Catheter Implantation
<ol>
	<li>Clean the workstation with 70% ethanol and cover the area with an absorbent cover (or use sterile flow hood).</li>
	<li>Attach catheter-needle to an empty 1 ml (TB) syringe. Cut a 1 inch square piece of parafilm and put a dab of surgical lubricant (approximately the size of a dime) on top. 
	NOTE: Two different needles are used for deposition of the catheter and for the inoculum to minimized accidental inoculation due to the mechanical manipulation necessary for catheter implantation. This also allows for the convenience of preparing fewer inoculation needles.</li>
	<li>Anesthetize C57BL/6 mice by putting them in a 32 ounce glass jar containing a tea-infuser ball with cotton balls soaked in 3 ml of isoflurane or vaporizer chamber (following manufactures protocol) until unconscious but still breathing normally (1 breath/sec).</li>
	<li>Then put the mouse on its back on a paper towel and spread the legs. Cover the nose of the mouse with a nose cone or 50 ml conical tube with cotton balls containing a small amount (approximately 1-2 ml) of isoflurane. 
	CAUTION: Isoflurane is an inhalation anesthetic. Use in a well-ventilated area and minimize inhalation by researcher.</li>
	<li>Gently palpitate the bladder to induce urination and ensure a voided bladder. Wipe periurethral area with a 100% ethanol wipe.</li>
	<li>Disinfect the periurethral area with 10% povidone-iodine solution using a cotton-tip applicator. Dab the inoculation needle/syringe, point first, into the surgical lubricant. 
	NOTE: Povidine-iodine is used for catheter implantation, which is a stronger aseptic solution than alcohol. Catheter implantation requires more mechanical manipulation to insert the catheter and thus a greater potential for contamination.</li>
	<li>Insert the catheter into the urethral opening. Once in, use tweezers to push the (7 mm PE10) long piece toward the bladder, consequently pushing the (5 mm silicone) small catheter and depositing it into the bladder. Remove the needle, with the 7 mm tubing still attached, immediately.</li>
</ol>
11. Bacterial Inoculation
<ol>
	<li>Follow the bacterial inoculation protocol in section 3, using the prepared inoculum from section 9. Remove the mouse from the nose cone and return it to its cage</li>
</ol>
12.&#160;At Each Time Point of Sacrifice
<ol>
	<li>Prepare 5 ml tubes for bladder and kidney (For organs follow step 4.1) and 1.5 ml Eppendorf tube for catheters. Add 1 ml of 1x PBS into 1.5 ml Eppendorf tube for catheter samples</li>
	<li>Follow steps 4.3 to 4.5. Dissect the mouse, harvesting the bladder, kidneys and catheter, placing the tissues independently into 5 ml tubes containing 1x PBS and the catheter into the 1.5 ml Eppendorf (see step 12.1). 
	NOTE: Use different scissors for the external dissection and for organ harvesting and catheter retrieval to minimize contamination</li>
	<li>Then follow step 4.6.</li>
</ol>
13.&#160;Bacterial Recovery
<ol>
	<li>For organs, follow steps 5.1 and 5.2. For bacterial recovery from catheters, vortex at maximum speed for 30 sec, sonicate the catheter samples for 5 min using a bath sonicator, and then vortex at maximum speed for an additional 30 sec.</li>
	<li>Make serial 1:10 dilutions out to 10-8 and plate each dilution for CFU enumeration on BHI plates. Incubate the plates at 37 &#186;C overnight and count colonies the next day.</li>
</ol>

The authors declare that they have no competing financial interests.

Uncomplicated community acquired UTI is a common and costly infection accounting for several million primary care visits every year 46. In addition, CAUTIs are a common healthcare acquired infection that has become extremely costly to healthcare providers as the Centers of Medicare and Medicaid Services no longer reimburses providers for the added cost of treatment resulting from hospital acquired CAUTI 45. The mouse models of UTI, both uncomplicated cystitis and CAUTI, described in these protocols ...

An erratum was issued for: <a href="https://www.jove.com/video/52892/establishment-and-characterization-of-uti-and-cauti-in-a-mouse-model">Establishment and Characterization of UTI and CAUTI in a Mouse Model</a>. The Protocol section has been updated.
The ethics statement has been updated from:
Ethics statement: The Washington University Animal Studies Committee approved all mouse infections and procedures as part of protocol number 20120216, which was approved 01/11/2013 and expires 01/11/2016. Overall care of the animals was consistent with The guide for the Care and Use of Laboratory Animals from the National Research Council and the USDA Animal Care Resource Guide. Euthanasia procedures are consistent with the &#8220;AVMA guidelines for the Euthanasia of Animals 2013 edition.&#8221;
to:
Ethics statement: The Washington University Animal Studies Committee approved all mouse infections and procedures as part of protocol number 20150226, which expires 12/10/2018. Overall care of the animals was consistent with The Guide for the Care and Use of Laboratory Animals from the National Research Council and the USDA Animal Care Resource Guide. Euthanasia procedures are consistent with the &#8220;AVMA guidelines for the Euthanasia of Animals 2013 edition.&#8221;
Step 3 has been updated from:
3. Bacterial Inoculation
<ol>
	<li>Clean the workstation with 70% ethanol and cover area with absorbent paper (or use sterile flow hood).</li>
	<li>Draw up to 0.9 ml of the prepared bacterial inoculum into a 1 ml (TB) syringe (remove air bubbles). Attach a prepared sterile inoculation needle with PE10 tubing, onto the syringe containing the inoculum, then sterilely trim the polyethylene tubing. 
	NOTE: Leave 1 mm of tubing above the tip of the needle to avoid puncturing the bladder.</li>
	<li>Cut a 1 inch square piece of parafilm and put a dab of surgical lubricant (approximately the size of a dime) on top.</li>
	<li>Anesthetize female C3H/HeN mice by putting them in a 32 ounce glass jar containing a tea-infuser ball with cotton balls soaked with 3 ml of isoflurane or vaporizer chamber (following manufactures protocol) until unconscious but still breathing normally (1 breath/sec). 
	NOTE: Some IACUC committees do not approve the use of a jar or vaporizer. Please follow the indication of the IACUC committee of your institution. 
	NOTE: If glass jar with tea-ball and/or nose cone with isoflurane-soakd cotton balls are used, the animal must be carefully observed to avoid anesthetic overdose and death. The advantage of using a vaporizer and anesthesia chamber is that it provides controlled isoflurane administration that avoids accidental overdoses. CAUTION: Isoflurane is an inhalation anesthetic. Use in a well-ventilated area and minimize inhalation.</li>
	<li>Remove the mouse from the jar/vaporizer and place it on its back on a paper towel and spread the legs.</li>
	<li>Cover the nose of the mouse with a nose cone (a tube connected to the vaporizer that provides a controlled isoflurance dose that comes equipped on some vaporizer units) or 50 ml conical tube with a cotton ball containing a small amount (approximately 1-2 ml) of isoflurane.</li>
	<li>Gently palpitate the bladder to induce urination and ensure a voided bladder. Wipe the periurethral area with 100% ethanol wipe. Dab the inoculation needle/syringe, point first, into the surgical lubricant.</li>
	<li>Inoculate each mouse with 50 &#181;l of the bacteria solution by inserting the inoculation needle transurethrally, approximately 12 mm, and pressing down on the syringe plunger gently to dispense the inoculum into the bladder gently (10 &#181;l/sec). Remove the inoculation needle from the mouse. 
	NOTE: Immediate return of inoculum at the urethral opening when beginning to inoculate indicates improper or incomplete insertion of the needle.</li>
	<li>Remove the mouse from nose cone and return it to its cage. Repeat steps 3.3-3.8 for each mouse. When/if switching inoculum conditions/strains, dispose of the syringe and inoculation needle in an approved sharps container and start again step 3.2.&#160;&#160; 
	NOTE: Inoculation with uropathogenic organisms generally does not cause severe pain symptoms. However, in rare instances, administering large doses of pathogens may cause fever, reduction in food and water intake and abnormal behavior. Animal health should be monitored throughout the experiment. If overt pain symptoms are notice, an analgesic, such as Buprenorphine (0.05&#8722;0.1 mg/kg given subcutaneously), can be applied. Procedures should be in accordance with each institution&#8217;s IACUC.</li>
</ol>
to:
3. Bacterial Inoculation
<ol>
	<li>Clean the workstation with 70% ethanol and cover area with absorbent paper (or use sterile flow hood).</li>
	<li>Draw up to 0.9 ml of the prepared bacterial inoculum into a 1 ml (TB) syringe (remove air bubbles). Attach a prepared sterile inoculation needle with PE10 tubing, onto the syringe containing the inoculum, then sterilely trim the polyethylene tubing. 
	NOTE: Leave 1 mm of tubing above the tip of the needle to avoid puncturing the bladder.</li>
	<li>Cut a 1 inch square piece of parafilm and put a dab of surgical lubricant (approximately the size of a dime) on top.</li>
	<li>Anesthetize female C3H/HeN mice by putting them in a vaporizer chamber (following manufactures protocol) until unconscious but still breathing normally (1 breath/sec). 
	NOTE: Some IACUC committees do not approve the use of a vaporizer. Please follow the indication of the IACUC committee of your institution. 
	CAUTION: Isoflurane is an inhalation anesthetic. Use in a well-ventilated area and minimize inhalation.</li>
	<li>Remove the mouse from the vaporizer and place it on its back on a paper towel and spread the legs.</li>
	<li>Cover the nose of the mouse with a nose cone (a tube connected to the vaporizer that provides a controlled isoflurance dose that comes equipped on some vaporizer units) to maintain anesthetization.</li>
	<li>Gently palpitate the bladder to induce urination and ensure a voided bladder. Wipe the periurethral area with 100% ethanol wipe. Dab the inoculation needle/syringe, point first, into the surgical lubricant.</li>
	<li>Inoculate each mouse with 50 &#181;l of the bacteria solution by inserting the inoculation needle transurethrally, approximately 12 mm, and pressing down on the syringe plunger gently to dispense the inoculum into the bladder gently (10 &#181;l/sec). Remove the inoculation needle from the mouse. 
	NOTE: Immediate return of inoculum at the urethral opening when beginning to inoculate indicates improper or incomplete insertion of the needle.</li>
	<li>Remove the mouse from nose cone and return it to its cage. Repeat steps 3.3-3.8 for each mouse. When/if switching inoculum conditions/strains, dispose of the syringe and inoculation needle in an approved sharps container and start again step 3.2.&#160;&#160; 
	NOTE: Inoculation with uropathogenic organisms generally does not cause severe pain symptoms. However, in rare instances, administering large doses of pathogens may cause fever, reduction in food and water intake and abnormal behavior. Animal health should be monitored throughout the experiment. If overt pain symptoms are notice, an analgesic, such as Buprenorphine (0.05&#8722;0.1 mg/kg given subcutaneously), can be applied. Procedures should be in accordance with each institution&#8217;s IACUC.</li>
</ol>

An erratum was issued for: <a href="https://www.jove.com/video/52892/establishment-and-characterization-of-uti-and-cauti-in-a-mouse-model">Establishment and Characterization of UTI and CAUTI in a Mouse Model</a>. The Protocol section has been updated.

Erratum: Establishment and Characterization of UTI and CAUTI in a Mouse Model

Urinary tract infections (UTIs) are one of the most common bacterial infections and can be divided into two categories based on the mechanism of acquisition, community and nosocomial acquired UTI. Community-acquired UTIs often occur in otherwise healthy women and studies have shown that approximately 50% of women will have at least one UTI in their lifetime 1. Additionally, recurrence is a major problem. A woman who has an initial acute infection has a 25-40% chance of having a second infection within six months despite appropriate antibiotic treatment and many women continue to have frequent recurrences 2. The bacteria that cause these infections are also becoming increasingly antibiotic resistant further confounding treatment protocols 3-6. UTI affect millions of individuals every year costing approximately 2.5 billion dollars in health care related expenses in the US, underscoring the impact and prevalence of the disease 1,7.Nosocomial acquired UTIs are mainly associated with the presence of foreign bodies such as indwelling catheters. Catheter-associated UTIs (CAUTI) remain the most common nosocomial acquired UTI, accounting for ~70-80% of such infections 8. Furthermore, CAUTI is associated with increased morbidity and mortality and it is the most common cause of secondary bloodstream infections 9.
UPEC associated community acquired UTIs are thought to be caused by the introduction of bacteria into the bladder from reservoirs in the gastrointestinal tract via mechanical manipulation during sexual intercourse, poor hygiene or other microbial population dynamics between different host niches 10. Once inside the bladder, UPEC employ numerous virulence factors, including capsule, iron acquisition systems, toxins, a virulence plasmid, tRNAs, pathogenicity islands and colonization factors that have been shown to play a role in pathogenesis 11-14. Critical to the establishment of UPEC colonization, UPEC also encode multiple types of adhesive chaperone usher pathway (CUP) pili that recognize receptors with stereochemical specificity 15. Type 1 pili, tipped with the FimH adhesin, are expressed by UPEC and bind mannosylated uroplakins 16 and &#945;-1, &#946;-3 integrins 17, which are expressed on the luminal surface of both human and mouse bladders 18. These FimH-mediated interactions facilitate bacterial colonization and invasion of the superficial epithelial cells19,20. Once inside the cell, UPEC can escape into the cytoplasm where a single bacterium can rapidly divide to form an intracellular bacterial community (IBC), which upon maturation, can contain ~104 bacteria 21. IBC formation has been demonstrated in at least six different mouse strains, C3H/HeN, C3H/HeJ, C57Bl/6, CBA, FVB/NJ and BALB/c, and with a wide variety of different UPEC strains and other Enterobacteriaceae 22-24. However temporal and spatial differences of IBC formation can vary depending upon the mouse background and the infecting UPEC strain. In C3H/HeN mice infected with the prototypical UPEC strains UTI89 or CFT073, IBC formation can be visualized as small biomasses of bacteria as early as 3 hpi (hr post infection). This community continues to expand and reaches a &#8220;midpoint&#8221; of development approximately 6 hpi when the rod shaped bacteria occupy a large percentage of the cytoplasmic space of terminally differentiated superficial umbrella cells These early IBCs form in a relatively synchronous manner with the majority displaying similar dimensions and morphologies. ~8 hpi the bacteria in the IBC change from a bacilli to cocci morphology. IBCs are transient in nature. Thus, IBC maturation from 12-18 hpi results in continued expansion of the bacterial population, followed by their filamentation and dispersal out of the cell with subsequent spread to neighboring cells 23. Thus, the IBC niche allows for rapid bacterial growth in an environment protected from host immune responses and antibiotics 25. The distinct stages of UPEC infection that are seen in mice are also observed in humans, such as IBCs and filamentation, supporting the mouse model of UTI as a beneficial tool that can be used to model UTI in humans 22,26-28.
While a majority of women experience a UTI in their lifetime, the outcome of these infections can range from acute self-limiting infection with no recurrence, to frequent recurrent cystitis. Further, studies have shown a strong familial occurrence of UTI, suggesting a genetic component contributes to UTI susceptibility 29. We have found that the differing UTI outcomes seen in clinics can be mirrored by the differing outcomes of experimental UPEC infection among inbred mouse strains 30. For example, C3H/HeN, CBA, DBA, and C3H/HeOuJ mice are susceptible, in an infectious dose-dependent manner, to long-lasting, chronic cystitis characterized by persistent, high titer bacteria (&#62;104 colony forming units (CFU)/ml), high titer bacterial bladder burdens at sacrifice &#62;4 weeks post-infection (wpi), chronic inflammation, and urothelial necrosis . These mice also display elevated serum levels of IL-6, G-CSF, KC, and IL-5 within the first 24 hpi that serve as biomarkers for the development of chronic cystitis. This may accurately represent the natural course of UTI in some women, as placebo studies have shown that a large percentage of women experiencing UTI will retain high levels of bacteria in their urine for several weeks after the first symptoms of cystitis if not given antibiotic treatment 31,32. Further, using C3H/HeN mice, we found that a history of chronic cystitis is a significant risk factor for subsequent severe recurrent infections. Recurrent UTI is the most significant clinical manifestation of UTI and the C3H/HeN mouse is currently the only studied model that recapitulates an increased predisposition after previous exposure. A second UTI outcome is recapitulated in C57Bl/6 mice where acute UPEC infection is self-limiting, with resolution of bladder inflammation and bacteriuria within approximately a week. Interestingly, in this model, UPEC readily form quiescent intracellular reservoirs within the bladder tissue from which UPEC are capable of emerging from a dormant state to reinitiate an active UTI, potentially explaining one mechanism for same strain recurrent UTI in humans 33,34.
In addition to genetic influences on UTI susceptibility, introduction of a catheter into the bladder greatly increases the likelihood of having an infection as well as increasing the range of bacteria able to cause an infection. It has been demonstrated that human urinary catheterization causes histological and immunological changes in the bladder due to mechanical stress that results in a robust inflammatory response, exfoliation, edema of the lamina propria and submucusa, urothelial thinning, and mucosal lesion of the urothelium and kidney 35,36. Additionally, the catheter provides a surface for bacterial attachment thereby creating an environment utilized by several species to cause CAUTI. While UPEC are still a major contributor, Enterococcus faecalis accounts for 15% of these CAUTI 37. E. faecalis is becoming increasingly resistant to antibiotics with vancomycin resistance emergence, posing a serious health concern 38. E. faecalis possess numerous virulence factors including toxins and adhesins necessary for attachment to both the catheter and epithelium 38. During urinary catheterization, the host is vulnerable to microbial adhesion, multiplication and dissemination in the urinary tract 39,40. E. faecalis forms a biofilm on the catheter as part of a mechanism to persist in the bladder and disseminate to the kidneys, which is reproduced in a mouse CAUTI model41. Recently, it has been shown during urinary catheterization, fibrinogen (Fg) is released into the bladder as part of the inflammatory response. Fg accumulates in the bladder, coats the catheter and is essential for E. faecalis biofilm formation, functioning as an attachment scaffold. In a C57BL/6 mouse model of CAUTI, we discovered that E. faecalis biofilm formation on the catheter, and thus persistence in the bladder, was dependent on the Ebp pilus, specifically its tip adhesin EbpA. We found that the N-terminal domain of EbpA specifically binds to Fg coating the catheter. Additionally, it was found that E. faecalis utilizes Fg as metabolite source during infection, thus enhancing biofilm formation 42.
Mouse models have proven critical to understanding as well as predicting clinical manifestations of UTI and CAUTI 41. In this article we demonstrate inoculum preparation of the cystitis UPEC isolate UTI89 and transurethral inoculation of C3H/HeN mice. Additionally, we demonstrate a protocol for catheter insertion in C57BL/6 mice and inoculation of the E. faecalis OG1RF strain. Both of these techniques lead to consistent and reliable UTI or CAUTI in mice. We also display techniques used to observe IBC formation during acute cystitis and urine collection for the analysis of chronic or recurrent cystitis. C3H/HeN mice have been used to study aspects of UPEC pathogenesis including initial bacterial invasion, IBC formation, filamentation and the development of chronic cystitis 23,33,43. These virulence parameters have also been studied in a variety of other mouse backgrounds 22,33. For CAUTI, the C57BL/6 model allows for foreign body implantation into the bladder with subsequent bacterial colonization, which can be maintained for 7 days post infection 41. These models have been useful for assessing bacterial virulence mechanisms, host responses to UTI and mechanisms to subvert host responses, much of which has been subsequently recapitulated or observed in clinical human populations.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Material for catheter and needle preparation:</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>30ga needles</td>
			<td>BD Precision Glide</td>
			<td>305106</td>
			<td>30Gx &#189; (0.3 mm x 13mm)</td>
		</tr>
		<tr>
			<td>PE10 polyethylene tubing</td>
			<td>BD</td>
			<td>427400</td>
			<td>Inside diameter -0.011 in (0.28 mm); outside diameter &#8211; 0.024 in (0.61 mm)</td>
		</tr>
		<tr>
			<td>RenaSIL 025 platinum cured silicon tubing</td>
			<td>Braintree Scientific, Inc</td>
			<td>SIL 025</td>
			<td>inside diameter-0.012 x outside diameter 0.025, 25 ft coil</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Material for infections:</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflourane &#8211; Isothesia</td>
			<td>Butler Schein</td>
			<td>29405</td>
			<td>250 mL</td>
		</tr>
		<tr>
			<td>Clear Glass Straight-Sided Jar</td>
			<td>Kimble Chase</td>
			<td>5413289V 21</td>
			<td></td>
		</tr>
		<tr>
			<td>Stainless Steel Tea Infuser</td>
			<td>Schefs-Amazon</td>
			<td></td>
			<td>Premium Loose Leaf Tea Infuser By Schefs - Stainless Steel - Large Capacity -</td>
		</tr>
		<tr>
			<td>Non-sterile cotton balls</td>
			<td>Fisherbrand</td>
			<td>22-456-880</td>
			<td></td>
		</tr>
		<tr>
			<td>50 ml Falcon tubes</td>
			<td>VWR</td>
			<td>89039-660</td>
			<td></td>
		</tr>
		<tr>
			<td>Isotec 3 -vaporizer</td>
			<td>Ohmeda</td>
			<td>1224478</td>
			<td></td>
		</tr>
		<tr>
			<td>Ear punch</td>
			<td>Fisher Scientific</td>
			<td>13-812-201</td>
			<td>(when necessary)</td>
		</tr>
		<tr>
			<td>Betadine solution</td>
			<td>Betadine solution</td>
			<td></td>
			<td>10% Povidie-iodine topical solution</td>
		</tr>
		<tr>
			<td>Q-tips</td>
			<td>Fisher Scientific</td>
			<td>22-037-924</td>
			<td>6 in</td>
		</tr>
		<tr>
			<td>Diapers for bench</td>
			<td>Fisherbrand</td>
			<td>14206 63</td>
			<td>Absorbent Underpads (20&#8221;X36&#8221;mats)</td>
		</tr>
		<tr>
			<td>Surgical lubricant</td>
			<td>Surgilube</td>
			<td>0281-0205-36</td>
			<td></td>
		</tr>
		<tr>
			<td>Dissecting scissor</td>
			<td>Fine Science tools, INC</td>
			<td>14084-08</td>
			<td></td>
		</tr>
		<tr>
			<td>Micro-Adson Forceps</td>
			<td>Fine Science tools, INC</td>
			<td>11018-12</td>
			<td></td>
		</tr>
		<tr>
			<td>1 ml syringe</td>
			<td>BD</td>
			<td>309659</td>
			<td>Tuberculin slip tip</td>
		</tr>
		<tr>
			<td>Parafilm</td>
			<td>Bemis</td>
			<td>PM996</td>
			<td>4 in x 125 FT</td>
		</tr>
		<tr>
			<td>Eppendorf rack</td>
			<td>Fisherbrand</td>
			<td>05-541-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Eppendorf tubes</td>
			<td>MIDSCI</td>
			<td>AVX-T-17-C</td>
			<td></td>
		</tr>
		<tr>
			<td>Harvesting catheters, bladders and kidneys:</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Homogenizer</td>
			<td>PRO Scientific INC</td>
			<td>Bio-Gen Pro 200</td>
			<td></td>
		</tr>
		<tr>
			<td>5 ml polypropylene round-bottom tube</td>
			<td>BD</td>
			<td>352063</td>
			<td>for organ homogenization</td>
		</tr>
		<tr>
			<td>Paper towel</td>
			<td>Georgia-Pacific</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>Pharmco-AAPER</td>
			<td>11100020S</td>
			<td>200 proof</td>
		</tr>
		<tr>
			<td>Costar&#8482; Clear Polystyrene 96-Well Plates</td>
			<td>Corning</td>
			<td>3788</td>
			<td></td>
		</tr>
		<tr>
			<td>1X Phosphate sodium saline</td>
			<td>Sigma-Aldrich</td>
			<td>P3813</td>
			<td></td>
		</tr>
		<tr>
			<td>BRANSONIC Ultrasonic cleaner 1210</td>
			<td>Branson Ultrasonics Corporation</td>
			<td>1210</td>
			<td></td>
		</tr>
		<tr>
			<td>IBC materials:</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>6-well tissue culture test plate</td>
			<td>Techno Plastic Products</td>
			<td>92006</td>
			<td></td>
		</tr>
		<tr>
			<td>Pins</td>
			<td>Fine Science Tools</td>
			<td>26002-20</td>
			<td></td>
		</tr>
		<tr>
			<td>Sylgard 184</td>
			<td>Dow Corning</td>
			<td>3097358-1004</td>
			<td>Silicone Elastomer Kit</td>
		</tr>
		<tr>
			<td>X-gal (5-bromo-4-chloro-3-indolyl-b-D-galactoside)</td>
			<td>Invitrogen</td>
			<td>15520-034</td>
			<td>Ultrapure</td>
		</tr>
		<tr>
			<td>N, N-Dimethylformamide</td>
			<td>Sigma Aldrich</td>
			<td>D4551</td>
			<td></td>
		</tr>
		<tr>
			<td>MgCl2 (Magnesium chloride)</td>
			<td>Sigma Aldrich</td>
			<td>M8266</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium deoxycholate</td>
			<td>Sigma Aldrich</td>
			<td>D6750</td>
			<td></td>
		</tr>
		<tr>
			<td>Nonidet-P40</td>
			<td>Roche</td>
			<td>11754599001</td>
			<td>Octylphenolpoly(ethyleneglycolether)n</td>
		</tr>
		<tr>
			<td>Potassium hexacyanoferrate(II) trihydrate (K-ferrOcyanide)</td>
			<td>Sigma Aldrich</td>
			<td>P3289</td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium hexacyanoferrate(III) (K-ferrIcyanide)</td>
			<td>Sigma Aldrich</td>
			<td>60299</td>
			<td></td>
		</tr>
	</tbody>
</table>

establishment and characterization of uti and cauti in a mouse model

Urinary tract infections (UTI) are highly prevalent, a significant cause of morbidity and are increasingly resistant to treatment with antibiotics. Females are disproportionately afflicted by UTI: 50% of all women will have a UTI in their lifetime. Additionally, 20-40% of these women who have an initial UTI will suffer a recurrence with some suffering frequent recurrences with serious deterioration in the quality of life, pain and discomfort, disruption of daily activities, increased healthcare costs, and few treatment options other than long-term antibiotic prophylaxis. Uropathogenic Escherichia coli (UPEC) is the primary causative agent of community acquired UTI. Catheter-associated UTI (CAUTI) is the most common hospital acquired infection accounting for a million occurrences in the US annually and dramatic healthcare costs. While UPEC is also the primary cause of CAUTI, other causative agents are of increased significance including Enterococcus faecalis. Here we utilize two well-established mouse models that recapitulate many of the clinical characteristics of these human diseases. For UTI, a C3H/HeN model recapitulates many of the features of UPEC virulence observed in humans including host responses, IBC formation and filamentation. For CAUTI, a model using C57BL/6 mice, which retain catheter bladder implants, has been shown to be susceptible to E. faecalis bladder infection. These representative models are being used to gain striking new insights into the pathogenesis of UTI disease, which is leading to the development of novel therapeutics and management or prevention strategies.

The intravesical models of uncomplicated and catheter associated UTI provide flexible platforms for elucidating the molecular mechanisms of bacterial pathogenesis, the impact of these diseases on host tissue, and the development and testing of novel approaches to manage these common and costly infections. Depending on the mouse strain and pathogen, intravesical inoculation can be used to study host-pathogen interactions to elucidate factors necessary for initiating or modulating acute (Figure 1 and <stro...

Watch this Scientific Journal Video about Establishment and Characterization of UTI and CAUTI in a Mouse Model at JoVE.com

Establishment and Characterization of UTI and CAUTI in a Mouse Model

The ability to model urinary tract infections (UTI) is crucial in order to be able to understand bacterial pathogenesis and spawn the development of novel therapeutics. This work&#8217;s goal is to demonstrate mouse models of experimental UTI and catheter associated UTI that recapitulate and predict findings seen in humans.

Urinary tract infections (UTI) are highly prevalent, a significant cause of morbidity and are increasingly resistant to treatment with antibiotics. ...

establishment-and-characterization-of-uti-and-cauti-in-a-mouse-model

Research

JoVE Journal

Medicine

19.8K Views.  Washington University School of Medicine. The ability to model urinary tract infections (UTI) is crucial in order to be able to understand bacterial pathogenesis and spawn the development of novel therapeutics. This work’s goal is to demonstrate mouse models of experimental UTI and catheter associated UTI that recapitulate and predict findings seen in humans.

Video: Establishment and Characterization of UTI and CAUTI in a Mouse Model

A Mouse Model of in Utero Transplantation

The transplantation of stem cells and viruses in utero has tremendous potential for treating congenital disorders in the human fetus. For example, in utero transplantation (IUT) of hematopoietic stem cells has been used to successfully treat patients with severe combined immunodeficiency.1,2 In several other conditions, however, IUT has been attempted without success.3 Given these mixed results, the availability of an efficient non-human model to study the biological sequelae of stem cell transplantation and gene therapy is critical to advance this field. We and others have used the mouse model of IUT to study factors affecting successful engraftment of in utero transplanted hematopoietic stem cells in both wild-type mice4-7 and those with genetic diseases.8,9 The fetal environment also offers considerable advantages for the success of in utero gene therapy. For example, the delivery of adenoviral10, adeno-associated viral10, retroviral11, and lentiviral vectors12,13 into the fetus has resulted in the transduction of multiple organs distant from the site of injection with long-term gene expression. in utero gene therapy may therefore be considered as a possible treatment strategy for single gene disorders such as muscular dystrophy or cystic fibrosis. Another potential advantage of IUT is the ability to induce immune tolerance to a specific antigen. As seen in mice with hemophilia, the introduction of Factor IX early in development results in tolerance to this protein.14 
In addition to its use in investigating potential human therapies, the mouse model of IUT can be a powerful tool to study basic questions in developmental and stem cell biology. For example, one can deliver various small molecules to induce or inhibit specific gene expression at defined gestational stages and manipulate developmental pathways. The impact of these alterations can be assessed at various timepoints after the initial transplantation. Furthermore, one can transplant pluripotent or lineage specific progenitor cells into the fetal environment to study stem cell differentiation in a non-irradiated and unperturbed host environment.
The mouse model of IUT has already provided numerous insights within the fields of immunology, and developmental and stem cell biology. In this video-based protocol, we describe a step-by-step approach to performing IUT in mouse fetuses and outline the critical steps and potential pitfalls of this technique.

A Mouse Model of in Utero Transplantation

The mouse model of in utero transplantation is a versatile tool that can be used to study the potential clinical applications of stem cell transplantation and gene therapy in the fetus. In this protocol, we present a general approach to performing this technique

The transplantation of stem cells and viruses in utero has tremendous potential for treating congenital disorders in the human fetus.  For example, in ...

Multi-photon Imaging of Tumor Cell Invasion in an Orthotopic Mouse Model of Oral Squamous Cell Carcinoma

Loco-regional invasion of head and neck cancer is linked to metastatic risk and presents a difficult challenge in designing and implementing patient management strategies. Orthotopic mouse models of oral cancer have been developed to facilitate the study of factors that impact invasion and serve as model system for evaluating anti-tumor therapeutics. In these systems, visualization of disseminated tumor cells within oral cavity tissues has typically been conducted by either conventional histology or with in vivo bioluminescent methods. A primary drawback of these techniques is the inherent inability to accurately visualize and quantify early tumor cell invasion arising from the primary site in three dimensions. Here we describe a protocol that combines an established model for squamous cell carcinoma of the tongue (SCOT) with two-photon imaging to allow multi-vectorial visualization of lingual tumor spread. The OSC-19 head and neck tumor cell line was stably engineered to express the F-actin binding peptide LifeAct fused to the mCherry fluorescent protein (LifeAct-mCherry). Fox1nu/nu mice injected with these cells reliably form tumors that allow the tongue to be visualized by ex-vivo application of two-photon microscopy. This technique allows for the orthotopic visualization of the tumor mass and locally invading cells in excised tongues without disruption of the regional tumor microenvironment. In addition, this system allows for the quantification of tumor cell invasion by calculating distances that invaded cells move from the primary tumor site. Overall this procedure provides an enhanced model system for analyzing factors that contribute to SCOT invasion and therapeutic treatments tailored to prevent local invasion and distant metastatic spread. This method also has the potential to be ultimately combined with other imaging modalities in an in vivo setting.

A comprehensive overview of the techniques involved in generating a mouse model of oral cancer and quantitative monitoring of tumor invasion within the tongue through multi-photon microscopy of labeled cells is presented. This system can serve as a useful platform for the molecular assessment and drug efficacy of anti-invasive compounds.

Loco-regional invasion of head and neck cancer is linked to metastatic risk and presents a difficult challenge in designing and implementing patient ...

Cardiopulmonary Bypass in a Mouse Model: A Novel Approach

As prolonged cardiopulmonary bypass becomes more essential during cardiac interventions, an increasing clinical demand arises for procedure optimization and for minimizing organ damage resulting from prolonged extracorporal circulation. The goal of this paper was to demonstrate a fully functional and clinically relevant model of cardiopulmonary bypass in a mouse. We report on the device design, perfusion circuit optimization, and microsurgical techniques. This model is an acute model, which is not compatible with survival due to the need for multiple blood drawings. Because of the range of tools available for mice (e.g., markers, knockouts, etc.), this model will facilitate investigation into the molecular mechanisms of organ damage and the effect of cardiopulmonary bypass in relation to other comorbidities.

This paper describes how to perform cardiopulmonary bypass in mice. This novel model will facilitate the investigation of the molecular mechanisms involved in organ damage.

As prolonged cardiopulmonary bypass becomes more essential during cardiac interventions, an increasing clinical demand arises for procedure optimization ...

Isometric Contractility Measurement of the Mouse Mesenteric Artery Using Wire Myography

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and drugs. It is widely used in many studies on the physiological functions of vascular smooth muscle, the pathogenesis of vascular diseases such as hypertension, and the development of smooth muscle relaxant drugs. The mouse is a widely used model animal with a large pool of disease models and genetically modified strains. We introduced this method to measure the isometric contraction of mouse mesenteric artery in detail. A 1.4-mm segment of mouse mesenteric resistance artery was isolated and mounted on a myograph chamber by passing two steel wires through its lumen. After equilibration and normalization steps, the vessel segment was potentiated by a high-K+ solution twice prior to the contraction assay. As an example of the application of this method in drug development, we measured the relaxant effect of a novel natural substance, neoliensinine, isolated from a Chinese herb, embryos of the lotus seed (Nelumbo nucifera Gaertn.) on mouse mesenteric arteries. The vessel segments mounted on the myograph chamber were stimulated with a high-K+ solution. When the force tension reached a stable sustained phase, cumulative doses of neoliensinine were added to the chamber. We found that neoliensinine had a dose-dependent relaxant effect on smooth muscle contraction, thus suggesting that it bears potential activity against hypertension. In addition, as the vessel segment can survive at least 4 hours after mounting and maintain contractility induced by the high-K+ solution for many times, we suggest that the wire myograph system may be used for the time-consuming process of drug screening.

The wire myograph technique is used to investigate vascular smooth muscle functions and screen new drugs. We report a detailed protocol for measuring the isometric contractility of the mouse mesenteric artery and for screening new relaxants of vascular smooth muscle.

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and ...

Establishment of a Severe Dry Eye Model Using Complete Dacryoadenectomy in Rabbits

Dry eye disease (DED) is a complex disease with multiple etiologies and variable symptoms, having ocular surface inflammation as its key pathophysiologic step. Despite advances in our understanding of DED, significant knowledge gaps remain. Advances are limited in part due to the lack of informative animal models. The authors recently reported on a method of DED induced by injecting all orbital lacrimal gland (LG) tissues with the lectin concanavalin A. Here, we report a novel model of aqueous-deficient DED based on the surgical resection of all orbital LG (dacryoadenectomy) tissues. Both methods use rabbits because of their similarity to human eyes in terms of the size and structure of the ocular surface. One week after removal of the nictitating membrane, the orbital superior LG was surgically removed under anesthesia, followed by removal of the palpebral superior LG, and finally removal of the inferior LG. Dacryoadenectomy induced severe DED, evidenced by a marked reduction in the tear break up time test and the Schirmer&#39;s tear test, and significantly increased tear osmolarity and rose bengal staining. Dacryoadenectomy-induced DED lasted at least eight weeks. There were no complications and animals tolerated the procedure well. The technique can be mastered relatively easily by those with adequate surgical experience and appreciation of the relevant rabbit anatomy. Since this model recapitulates the features of human aqueous-deficient DED, it is suitable for studies of ocular surface homeostasis, DED, and candidate therapeutics.

A novel approach is presented to induce chronic dry eye disease in rabbits by surgically removing all orbital lacrimal glands. This method, distinct from those previously reported, produces a stable, reproducible model of aqueous deficient dry eye well suited to study tear physiology and pathophysiology and ocular therapeutics.

Dry eye disease (DED) is a complex disease with multiple etiologies and variable symptoms, having ocular surface inflammation as its key pathophysiologic ...

Establishment of a Mouse Severe Acute Pancreatitis Model using Retrograde Injection of Sodium Taurocholate into the Biliopancreatic Duct

The prevalence of acute pancreatitis (AP), especially severe acute pancreatitis (SAP), is increasing in younger age groups annually. However, there is a lack of effective treatments in the current clinical practice. With the easy accessibility of transgenic and knockout strains and their small size, which allows minimal doses of drugs required for in vivo evaluation, a well-established experimental model in mice is preferred for AP research. Moreover, SAP induced through sodium taurocholate (TC) is currently one of the most widely used and best characterized models. This model has been investigated for novel therapies and possible molecular events during the process of AP. Here, we present the generation of an AP mouse model using sodium taurocholate and a simple homemade microsyringe. Moreover, we also provide the methodology for the subsequent histology and serological testing.

A mouse model of severe acute pancreatitis is described herein. The procedure presented here is very rapid, simple, and accessible, thereby potentially allowing the study of the molecular mechanisms and different therapeutic interventions in acute pancreatitis in a convenient way.

The prevalence of acute pancreatitis (AP), especially severe acute pancreatitis (SAP), is increasing in younger age groups annually. However, there is a ...

A Neonatal BALB/c Mouse Model of Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is the most severe gastrointestinal (GI) disease that often occurs in premature infants, especially very low birth weight infants, with high mortality and unclear pathogenesis. The cause of NEC may be related to inflammatory immune regulatory system abnormalities. An NEC animal model is an indispensable tool for NEC disease immune research. NEC animal models usually use C57BL/6J neonatal mice; BALB/c neonatal mice are rarely used. Related studies have shown that when mice are infected, Th2 cell differentiation is predominant in BALB/c mice compared to C57BL/6J mice. Studies have suggested that the occurrence and development of NEC are associated with an increase in T helper type 2 (Th2) cells and are generally accompanied by infection. Therefore, this study used neonatal BALB/c mice to induce an NEC model with similar clinical characteristics and intestinal pathological changes as those observed in children with NEC. Further study is warranted to determine whether this animal model could be used to study Th2 cell responses in NEC.

Necrotizing enterocolitis (NEC) is the most severe gastrointestinal (GI) disease that often occurs in premature infants, especially very low birth weight infants, with high mortality and unclear pathogenesis. The cause of NEC may be related to inflammatory immune regulatory system abnormalities. An NEC animal model is an indispensable tool for NEC disease immune research. NEC animal models usually use C57BL/6J neonatal mice; BALB/c neonatal mice are rarely used. Related studies have shown that when mice are infected, Th2 cell differentiation is predominant in BALB/c mice compared to C57BL/6J mice. Studies have suggested that the occurrence and development of NEC are associated with an increase in T helper type 2 (Th2) cells and are generally accompanied by infection. Therefore, this study used neonatal BALB/c mice to induce an NEC model with similar clinical characteristics and intestinal pathological changes as those observed in children with NEC. Further study is warranted to determine whether this animal model could be used to study Th2 cell responses in NEC.

Necrotizing enterocolitis (NEC) is the most severe gastrointestinal (GI) disease that often occurs in premature infants, especially very low birth weight ...

Establishment and Evaluation of a Porcine Vein Graft Disease Model

Venous graft disease (VGD) is the leading cause of coronary artery bypass graft (CABG) failure. Large animal models of CABG-VGD are needed for the investigation of disease mechanisms and the development of therapeutic strategies. 
To perform the surgery, we enter the cardiac chamber through the third intercostal space and carefully dissect the internal mammary vein and immerse it in normal saline. The right main coronary artery is then treated for ischemia. The target vessel is incised, a shunt plug is placed, and the distal end of the graft vein is anastomosed. The ascending aorta is partially blocked, and the proximal end of the graft vein is anastomosed after perforation. The graft vein is checked for patency, and the proximal right coronary artery is ligated. 
CABG surgery is performed in minipigs to harvest the left internal mammary vein for its use as a vascular graft. Serum biochemical tests are used to evaluate the physiological status of the animals after surgery. Ultrasound examination shows that the proximal, middle, and distal end of the graft vessel are unobstructed. In the surgical model, turbulent blood flow in the graft is observed upon histological examination after the CABG surgery, and venous graft stenosis associated with intimal hyperplasia is observed in the graft. The study here provides detailed surgical procedures for the establishment of a repeatable CABG-induced VGD model.

In this protocol, novel pig vein bypass grafting was performed through a small incision in the left chest wall without cardiopulmonary bypass. A postoperative pathology study was done, which showed intimal thickening.

Venous graft disease (VGD) is the leading cause of coronary artery bypass graft (CABG) failure. Large animal models of CABG-VGD are needed for the ...

Establishment of a Simple and Effective Rat Model for Intraoperative Parathyroid Gland Imaging

Parathyroid gland (PG) identification is a critical unmet need in thyroidectomy. The identification of the PG is challenging in thyroid surgery as it is similar in color to the thyroid gland. The lack of effective animal models in preclinical research is a severe limitation for the development of PG identification techniques. This protocol allows for the establishment of a simple and effective rat model for PG identification. In this model, black iron oxide nanoparticles (IONPs) are injected locally in the thyroid gland and rapidly diffuse within the thyroid gland but not the PG. A negatively stained PG and a positively stained thyroid gland can be easily identified by the naked eye without requiring external microscopes. The position of the PG can be identified by increasing the color contrast between the thyroid gland and the PG, based on the color of the black IONPs. This rat model is low-cost and convenient for PG identification, and the IONPs are a novel PG contrast agent.

To date, the development of parathyroid gland (PG) identification methods is limited by the lack of animal models in preclinical research. Here, we establish a simple and effective rat model for intraoperative PG imaging and evaluate its effectiveness by using iron oxide nanoparticles as a novel PG contrast agent.

Parathyroid gland (PG) identification is a critical unmet need in thyroidectomy. The identification of the PG is challenging in thyroid surgery as it is ...

Modified Arteriovenous Fistula Surgery to Establish the RV Volume Overload Mouse Model

Establishment and Confirmation of a Postnatal Right Ventricular Volume Overload Mouse Model

Right ventricular (RV) volume overload (VO) is common in children with congenital heart disease. In view of distinct developmental stages,the RV myocardium may respond differently to VO in children compared to adults. The present study aims to establish a postnatal RV VO model in mice using a modified abdominal arteriovenous fistula. To confirm the creation of VO and the following morphological and hemodynamic changes of the RV, abdominal ultrasound, echocardiography, and histochemical staining were performed for 3 months. As a result, the procedure in postnatal mice showed an acceptable survival and fistula success rate. In VO mice, the RV cavity was enlarged with a thickened free wall, and the stroke volume was increased by about 30%-40% within 2 months after surgery. Thereafter, the RV systolic pressure increased, corresponding pulmonary valve regurgitation was observed, and small pulmonary artery remodeling appeared. In conclusion, modified arteriovenous fistula (AVF) surgery is feasible to establish the RV VO model in postnatal mice. Considering the probability of fistula closure and elevated pulmonary artery resistance, abdominal ultrasound and echocardiography must be performed to confirm the model status before application.

Author Spotlight: Establishment and Confirmation of a Postnatal Right Ventricular Volume Overload Mouse Model  

This protocol presents the establishment and confirmation of a postnatal right ventricular volume overload (VO) model in mice with abdominal arteriovenous fistula (AVF), which can be applied to investigate how VO contributes to postnatal heart development.