Dr. de Caestecker's laboratory is supported by NIH 1RO1 HL093057-01 and 1RC4DK090770-01. Dr. Harris' laboratory is supported by DK38226,DK51265, DK62794 and funding from the Veterans Administration. Support for mouse kidney injury surgeries, serum creatinine, and fibrosis assays also provided by the Vanderbilt O'Brien Kidney Injury Center grant 1P30 DK079341.

<ol>
	<li>Autoclave all surgical instruments before surgery. Note that if one is performing multiple surgeries on different mice, rinse instruments after use and then sterilize using a hot bead sterilizer. It is not sufficient to soak in 70% ethanol.</li>
	<li>Give 0.5 ml S/C sterile normal saline preoperatively and immediately postoperatively to compensate for loss of body fluid during surgery.</li>
	<li>Weigh the mice.</li>
	<li>Anesthetize mouse using IP Xylazine/Ketamine mixture. It usually takes 3-5 min for the mice to reach surgical plane anesthesia.</li>
	<li>Shave the surgical site with enough border area to keep hair from contaminating the incision site. This needs to be performed in a preparatory area, not where the surgery is performed.</li>
	<li>Apply ophthalmic lubricating ointment to the eyes to prevent drying during the procedure.</li>
	<li>Place the mouse prone on the heated surface covered with absorbent bench pad. Tape legs to the surgical surface.</li>
	<li>If using the water bath system, set heat at 38 &deg;C 1 hr prior to surgery.</li>
	<li>Aseptic preparation using Betadine solution swab stick: scrub from the center of the site towards the periphery 3x, each time followed by scrubbing with Nolvasan to remove the Betadine. All Betadine should be removed from the surgical field prior to incision by rinsing with Nolvasan. Before starting aseptic procedure gloves should be changed to be sterile.</li>
	<li>Cover surgical field with a sterile surgical drape. This will prevent stray hair from entering the surgical field and provide an area on which to lay sterile instruments during surgery.</li>
	<li>Palpate kidney location through the skin.</li>
	<li>Cut the dorsal skin along the midline of mouse (approximately 1.5 cm) using scissors and forceps.</li>
	<li>Separate skin and subcutaneous layers over the left and right dorsal sides through this incision by blunt dissection using scissors and forceps.</li>
	<li>Make a small incision through the right flank muscle and fascia above the kidney and exteriorize the right kidney.</li>
	<li>Carefully dissect the upper and lower poles of the kidney free from surrounding tissue. Note that fatty tissue from around the upper pole contains the adrenal gland carrying its own blood supply which can be pushed off the kidney but obviously should not be removed from the mouse (Figure 1). After liberating kidney from surrounding tissue, tie the 4-0 silk suture around the hilum of the right kidney using a double surgical knot. Leave one end of the suture ~2 in long to hold up the kidney as you are cutting distal to the knot so you can visualize the site to be cut. Irrigate the stump with sterile saline.</li>
	<li>Close the muscle layer by using absorbable suture.</li>
	<li>Make a small incision through the left flank muscle and fascia above the kidney and exteriorize the left kidney (Figure 2A).</li>
	<li>Carefully hold kidney using blunt forceps while releasing renal pedicle from surrounding fat tissue using forceps (Figures 2B-2F). Too much pressure on the kidney using the blunt forceps may cause renal injury so one needs to remember this when designing "sham" controls for the studies. If you find that your sham controls are developing renal injury (as evidenced by a rise in serum creatinine), an alternative method you may consider to release the surrounding fat tissue from the renal pedicle is to gently roll the tissues with saline soaked sterile cotton-tipped swabs. In our experience the fat is fairly tightly attached to the renal pedicle and cannot easily be removed with cotton swabs, so this may not be the first approach you would want to use. However, like other aspects of this model, this is something that you will have to establish for yourself with practice and experience.</li>
	<li>Clamp left renal pedicle using non traumatic vascular clamp using holding forceps (to facilitate clamp placement), use timer for different clamp times depending on the mouse strain and injury severity required (see Table 1).</li>
	<li>Cover the left kidney with the skin (Figure 2H).</li>
	<li>Cover skin incision with saline soaked gauze.</li>
	<li>Exteriorize kidney, confirm uniform dusky appearance and release the clamp after the indicated times, and confirm that dusky appearance reverses uniformly throughout the kidney (Figure 2I/G). If the kidney does not rapidly and uniformly re-perfuse (pink up) the mouse should be excluded from further analysis. Gently push kidney back into the retroperitoneal space.</li>
	<li>Close the muscle layer using absorbable suture.</li>
	<li>Close the skin layer using monofilament nylon non-absorbable suture.</li>
	<li>Administer buprenorphine analgesia.</li>
	<li>Transfer mice away from the surgical field onto a heating pad until they wake.</li>
	<li>Return the mice to animal room.</li>
	<li>Closely monitor the mice and give additional doses of buprenorphine as indicated above every 8-12 hr for pain or discomfort. Clinical signs resulting in administration of analgesics include depression or other behavioral changes, abnormal appearance, or posture such as pilo-erection, hunched posture, lack of grooming and eating, or immobility.</li>
</ol>

<ol>
	<li>Singh, A. P., Junemann, A., Muthuraman, A., Jaggi, A. S., Singh, N., Grover, K., Dhawan, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+models+of+acute+renal+failure.">Animal models of acute renal failure.</a> Pharmacological reports: PR. 64, 31-44 (2012).</li><li>Heyman, S. N., Rosenberger, C., Rosen, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+ischemia-reperfusion:+Biases+and+myths-the+proximal+vs.+Distal+hypoxic+tubular+injury+debate+revisited.">Experimental ischemia-reperfusion: Biases and myths-the proximal vs. Distal hypoxic tubular injury debate revisited.</a> Kidney Int. 77, 9-16 (2010).</li><li>Lieberthal, W., Nigam, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acute+renal+failure.+II.+Experimental+models+of+acute+renal+failure:+Imperfect+but+indispensable.">Acute renal failure. II. Experimental models of acute renal failure: Imperfect but indispensable.</a> Am. J. Physiol. Renal Physiol. 278, F1-F12 (2000).</li><li>Dunn, S. R., Qi, Z., Bottinger, E. P., Breyer, M. D., Sharma, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Utility+of+endogenous+creatinine+clearance+as+a+measure+of+renal+function+in+mice.">Utility of endogenous creatinine clearance as a measure of renal function in mice.</a> Kidney Int. 65, 1959-1967 (2004).</li><li>Yuen, P. S., Dunn, S. R., Miyaji, T., Yasuda, H., Sharma, K., Star, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simplified+method+for+HPLC+determination+of+creatinine+in+mouse+serum.">A simplified method for HPLC determination of creatinine in mouse serum.</a> Am. J. Physiol. Renal Physiol. 286, F1116-F1119 (2004).</li><li>Hetu, P. O., Gingras, M. E., Vinet, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+and+validation+of+a+rapid+liquid+chromatography+isotope+dilution+tandem+mass+spectrometry+(LC-IDMS/MS)+method+for+serum+creatinine.">Development and validation of a rapid liquid chromatography isotope dilution tandem mass spectrometry (LC-IDMS/MS) method for serum creatinine.</a> Clin. Biochem. 43, 1158-1162 (2010).</li><li>Keppler, A., Gretz, N., Schmidt, R., Kloetzer, H. M., Groene, H. J., Lelongt, B., Meyer, M., Sadick, M., Pill, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasma+creatinine+determination+in+mice+and+rats:+An+enzymatic+method+compares+favorably+with+a+high-performance+liquid+chromatography+assay.">Plasma creatinine determination in mice and rats: An enzymatic method compares favorably with a high-performance liquid chromatography assay.</a> Kidney Int. 71, 74-78 (2007).</li><li>Yang, L., Besschetnova, T. Y., Brooks, C. R., Shah, J. V., Bonventre, J. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epithelial+cell+cycle+arrest+in+G2/M+mediates+kidney+fibrosis+after+injury.">Epithelial cell cycle arrest in G2/M mediates kidney fibrosis after injury.</a> Nat. Med. 16, 535-543 (2010).</li><li>Shanley, P. F., Rosen, M. D., Brezis, M., Silva, P., Epstein, F. H., Rosen, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Topography+of+focal+proximal+tubular+necrosis+after+ischemia+with+reflow+in+the+rat+kidney.">Topography of focal proximal tubular necrosis after ischemia with reflow in the rat kidney.</a> Am. J. Pathol. 122, 462-468 (1986).</li><li>Chawla, L. S., Amdur, R. L., Amodeo, S., Kimmel, P. L., Palant, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+severity+of+acute+kidney+injury+predicts+progression+to+chronic+kidney+disease.">The severity of acute kidney injury predicts progression to chronic kidney disease.</a> Kidney Int. 79, 1361-1369 (2012).</li><li>Lo, L. J., Go, A. S., Chertow, G. M., McCulloch, C. E., Fan, D., Ordonez, J. D., Hsu, C. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dialysis-requiring+acute+renal+failure+increases+the+risk+of+progressive+chronic+kidney+disease.">Dialysis-requiring acute renal failure increases the risk of progressive chronic kidney disease.</a> Kidney Int. 76, 893-899 (2009).</li><li>Burne, M. J., Haq, M., Matsuse, H., Mohapatra, S., Rabb, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+susceptibility+to+renal+ischemia+reperfusion+injury+revealed+in+a+murine+model.">Genetic susceptibility to renal ischemia reperfusion injury revealed in a murine model.</a> Transplantation. 69, 1023-1025 (2000).</li><li>Muller, V., Losonczy, G., Heemann, U., Vannay, A., Fekete, A., Reusz, G., Tulassay, T., Szabo, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sexual+dimorphism+in+renal+ischemia-reperfusion+injury+in+rats:+Possible+role+of+endothelin.">Sexual dimorphism in renal ischemia-reperfusion injury in rats: Possible role of endothelin.</a> Kidney Int. 62, 1364-1371 (2002).</li><li>Schmitt, R., Marlier, A., Cantley, L. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zag+expression+during+aging+suppresses+proliferation+after+kidney+injury.">Zag expression during aging suppresses proliferation after kidney injury.</a> J. Am. Soc. Nephrol. 19, 2375-2383 (2008).</li><li>Oxburgh, L., de Caestecker, M. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ischemia-reperfusion+injury+of+the+mouse+kidney.">Ischemia-reperfusion injury of the mouse kidney.</a> Methods Mol. Biol. 886, 363-379 (2012).</li></ol>

Authors have no conflicts of interest to disclose.

We describe two models of IR-AKI to study the effects of moderate and severe renal injury. These models allow us to induce consistent and predictable injury with low mortality. Our protocol outlines many of the difficulties and pitfalls traditionally associated with this model. Moreover, we have shown that depending on the length of renal pedicle clamping, the model induces a largely reversible mild and moderate AKI, or more severe AKI with incomplete recovery and persistent renal fibrosis. Post-injury fibrosis in the se...

A variety of experimental models of acute kidney injury (AKI) have been developed to match the diversity and complexity of the human condition (see reference for a recent, comprehensive review1). Each of these models has its own strengths and weaknesses, and while each mimics the corresponding human conditions with varied efficiencies, none precisely model the pathophysiology of their human counterparts. Ischemia reperfusion (IR)-induced AKI has been developed as a model of acute ischemia-induced renal injury in rodents. While the severity of renal tubular injury seen in this model is rarely observed in patients with renal hypoperfusion injuries2, despite its limitations and largely because of the relatively reproducible nature of this model, its extensive use has provided and, it is expected, will continue to provide important insights into many of the common basic mechanisms of AKI, repair, and therapy3. IR surgery requires familiarity with the mouse kidney anatomy, which we have illustrated in a simplified form in Figure 1. Renal ischemia-reperfusion (IR) injury surgery can be performed via ventral (laparotomy) or dorsal (retroperitoneal) approaches. We use a dorsal approach since it is less traumatic, allowing faster recovery times and improved survival (particularly when first learning the procedure). Renal IR injury can be performed unilaterally or bilaterally. However, differences between effective clamp pressures (which may result from interposition of perihilar fat between the clamp jaws) and/or differences in renal responses to ischemia between sides leads to more variable results. While this is not an insurmountable problem, it can increase variability between experiments, which is a major issue for this model. Unilateral IR can be performed with contra-lateral nephrectomy. This is our method of choice since it reduces variability in clamping between pedicles, and at the same time allows one to evaluate renal function, which is unaffected with unilateral IR alone. There has been discussion about what is the most practical vs. optimal method to assess renal function in mice. Blood urea nitrogen (BUN) provides a measure of renal function and is a useful "first look" marker in some models of AKI, including IR injury. However, BUN levels can be affected by volume status of the mice which may be affected, particularly following ventral approach IR injury, when delayed recovery reduces oral intake of fluids for a number of days post-surgery. Serum creatinine is less influenced by hydration status but is clearly affected by muscle mass. One of the difficulties with serum creatinine measurements has been problems with detection of non-creatinine chromogens in mouse serum using picric acid based techniques. As an alternative, a number of centers have developed an HPLC-based method to quantify mouse creatinine that is not affected by this artifact4. However, unlike BUN and picric acid creatinine assays, which only require 5-10 &mu;l of serum, HPLC-assays require ~ 25 &mu;l serum per assay, which if performed in duplicate will require ~100 &mu;l of whole blood per assay. This can be limiting for mouse studies. Some centers have developed more sensitive HPLC and Mass Spectrometry-based methods that allow analysis of smaller sample volumes5, 6. However, these technologies are not widely available. An alternative, enzymatic cascade assay (which requires only 5-10 &mu;l of serum) has been evaluated in mouse and rat serum samples and shown to closely parallel HPLC measurements of serum creatinine while picric acid assays always over-estimate creatinine values7 . While this assay is not widely used in the AKI literature, the assay is commercially available, simple to use, and we find gives reliable results with this model of IR-induced AKI in mice.

<table><tbody><tr><td>Ketamine (anesthetic)</td><td>Webster Veterinary</td><td>07-881-9413 (100 mg/ml)</td><td>Final concentration 30 mg/ml Ketamine with 3 mg/ml Xylazine administered at 3-4 ml/kg (100 mg/kg Ketamine and 10 mg/kg Xylazine)</td></tr><tr><td>Xylazine (analgesic)</td><td>Webster Veterinary</td><td>07-808-1939 (100 mg/ml)</td><td>As above</td></tr><tr><td>Antisedan (anti-Xylazine)</td><td>Webster Veterinary</td><td>07-867-7097 (5 mg/ml)</td><td>Optional: to reverse effects of Xylazine in order to increase the rate of recovery after surgery Use 0.5-0.7 mg/kg</td></tr><tr><td>Buprenorphine (analgesic)</td><td>Bedford Laboratories</td><td>NDC 55390-100-10 (0.3 mg/ml)</td><td>Dose 0.05-0.1 &amp;mu;g/g every 8-12 hr. Make up a 1:5 dilution in sterile normal saline preoperatively and give 2.5-5 &amp;mu;l/g of the diluted solution.</td></tr><tr><td>Ophthalmic ointment</td><td>Dechra</td><td>NDC 17033-211-38</td><td>&amp;nbsp;</td></tr><tr><td>Betadine swab sticks</td><td>Purdue Products L.P.</td><td>NDC 67618-153-01</td><td>&amp;nbsp;</td></tr><tr><td>Nolvasan Surgical Scrub</td><td>Pfizer Animal Care</td><td>300253</td><td>&amp;nbsp;</td></tr><tr><td colspan="4">&lt;strong&gt;Table 2. Drugs and solutions for I/R surgery.&lt;/strong&gt;</td></tr><tr><td>Iris Scissors</td><td>Integra Miltex</td><td>VWR 21909-404</td><td>For skin and muscle dissection</td></tr><tr><td>Curved iris forceps</td><td>FST</td><td>11065-07</td><td>To hold skin and muscle, to remove peri-nephric fat</td></tr><tr><td>Blunt forceps</td><td>ROBOZ</td><td>RS-5228</td><td>To manipulate kidneys</td></tr><tr><td>Vascular clamp (795 g pressure)</td><td>ROBOZ</td><td>RS-5459</td><td>Good for C57BL/6 and BALB/c mice strains</td></tr><tr><td>Schwartz clip applying forceps</td><td>ROBOZ</td><td>RS-5450</td><td>For RS-5459 clamps</td></tr><tr><td>Vascular clamp (75-85 g pressure)</td><td>FST</td><td>18055-02</td><td>Optimal for CD1 mice strain, but also can be used for C57BL/6 and BALB/c</td></tr><tr><td>Micro-Serrefine Clamp Applicator-14 cm with Lock</td><td>FST</td><td>18056-14</td><td>For FST 18055-02 clamps</td></tr><tr><td>Gayman T/Pump (water-bath heated platform)</td><td>Braintree Scientific</td><td>TP-650</td><td>The water heater is set at 38 &amp;deg;C 1 hr prior surgery</td></tr><tr><td>15&quot; W x 24&quot; Heated platform</td><td>Braintree Scientific</td><td>HHP-2</td><td>Connect to Gayman heated water pump</td></tr><tr><td>Heating pad</td><td>Braintree Scientific</td><td>Model 39DP</td><td>Uses microwave for heating. This is useful for warming during recovery</td></tr><tr><td>Absorbable suture (Vicryl 5-0)</td><td>ETHICON</td><td>VCP834G</td><td>For fascia and muscle</td></tr><tr><td>Non-absorbable suture: monofilament nylon MONOMID 6/0 660B)</td><td>CP Medical</td><td>CP-B660B-03</td><td>For skin</td></tr><tr><td>Halsey needle holder: Tungsten Carbide/13 cm</td><td>FST</td><td>12501-13</td><td>To hold suture needles</td></tr><tr><td>Timer</td><td>FST</td><td>06-662-3</td><td>To quantify ischemia time</td></tr><tr><td>Hot bead sterilizer</td><td>FST</td><td>18000-45</td><td>To sterilize instruments between mice if you are performing multiple surgeries (it is not sufficient to soak instruments in ethanol)</td></tr><tr><td>Electric razor</td><td>Braintree Scientific</td><td>CLP-22965</td><td>&amp;nbsp;</td></tr><tr><td>Tape</td><td>Durapore</td><td>1538-0</td><td>&amp;nbsp;</td></tr><tr><td>1 ml Syringe</td><td>EXELint</td><td>26044</td><td>&amp;nbsp;</td></tr><tr><td>Sterile cotton tipped applicators</td><td>Kendall</td><td>8884541300</td><td>&amp;nbsp;</td></tr><tr><td>Absorbent BenchPad</td><td>VWR</td><td>56617-014</td><td>&amp;nbsp;</td></tr><tr><td>Surgical drapes</td><td>VWR</td><td>21902-985</td><td>Need to be autoclaved</td></tr><tr><td>2&amp;rsquo;&amp;rsquo; x 2&amp;rsquo;&amp;rsquo; Gauze Pads</td><td>Medi-First</td><td>60673</td><td>&amp;nbsp;</td></tr><tr><td>Sterile gloves</td><td>Cardinal Health</td><td>2D7251</td><td>&amp;nbsp;</td></tr><tr><td colspan="4">&lt;strong&gt;Table 3. Equipment and instruments for I/R surgery.&lt;/strong&gt;</td></tr></tbody></table>

ischemia-reperfusion model of acute kidney injury and post injury fibrosis in mice

Ischemia-reperfusion induced acute kidney injury (IR-AKI) is widely used as a model of AKI in mice, but results are often quite variable with high, often unreported mortality rates that may confound analyses. Bilateral renal pedicle clamping is commonly used to induce IR-AKI, but differences between effective clamp pressures and/or renal responses to ischemia between kidneys often lead to more variable results. In addition, shorter clamp times are known to induce more variable tubular injury, and while mice undergoing bilateral injury with longer clamp times develop more consistent tubular injury, they often die within the first 3 days after injury due to severe renal insufficiency. To improve post-injury survival and obtain more consistent and predictable results, we have developed two models of unilateral ischemia-reperfusion injury followed by contralateral nephrectomy. Both surgeries are performed using a dorsal approach, reducing surgical stress resulting from ventral laparotomy, commonly used for mouse IR-AKI surgeries. For induction of moderate injury BALB/c mice undergo unilateral clamping of the renal pedicle for 26 min and also undergo simultaneous contralateral nephrectomy. Using this approach, 50-60% of mice develop moderate AKI 24 hr after injury but 90-100% of mice survive. To induce more severe AKI, BALB/c mice undergo renal pedicle clamping for 30 min followed by contralateral nephrectomy 8 days after injury. This allows functional assessment of renal recovery after injury with 90-100% survival. Early post-injury tubular damage as well as post injury fibrosis are highly consistent using this model.

Moderate IR-induced AKI. Unilateral IR with simultaneous contralateral nephrectomy substantially reduces variability in results, but with shorter clamp times necessary for the mice to survive this procedure, we still found that only 50-60% of mice developed the expected renal insufficiency 24 hr after injury (Figure 3A). In practical terms this creates difficulties evaluating data unless the studies involve treatment regimens that can be initiated at least 24 hr after injury, allowing ti...

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Ischemia-reperfusion Model of Acute Kidney Injury and Post Injury Fibrosis in Mice

We describe models of moderate and severe ischemia-reperfusion-induced kidney injury in which the mice undergo unilateral renal pedicle clamping followed by simultaneous or delayed contralateral nephrectomy, respectively. These models consistently give rise to renal dysfunction and post-injury fibrosis, but injury severity and survival are dependent on mouse background, age and surgical equipment.

Ischemia-reperfusion induced acute kidney injury (IR-AKI) is widely used as a model of AKI in mice, but results are often quite variable with high, often ...

ischemia-reperfusion-model-acute-kidney-injury-post-injury-fibrosis

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39.5K Views.  Vanderbilt University Medical Center. We describe models of moderate and severe ischemia-reperfusion-induced kidney injury in which the mice undergo unilateral renal pedicle clamping followed by simultaneous or delayed contralateral nephrectomy, respectively. These models consistently give rise to renal dysfunction and post-injury fibrosis, but injury severity and survival are dependent on mouse background, age and surgical equipment.

Video: Ischemia-reperfusion Model of Acute Kidney Injury and Post Injury Fibrosis in Mice

Normothermic Cardiac Arrest and Cardiopulmonary Resuscitation: A Mouse Model of Ischemia-Reperfusion Injury

Acute Kidney Injury (AKI) is a common, highly lethal, complication of critical illness which has a high mortality1-4 and which is most 
frequently caused by whole-body hypoperfusion.5,6 Successful reproduction of whole-body hypoperfusion in rodent models has been fraught with 
difficulty.7-9,9,10 Models which employ focal ischemia have repeatedly demonstrated results which do not translate to the clinical setting, and larger 
animal models which allow for whole body hypoperfusion lack access to the full toolset of genetic manipulation possible in the mouse.11,12 However, in recent 
years a mouse model of cardiac arrest and cardiopulmonary resuscitation has emerged which can be adapted to model AKI.13 This model reliably reproduces 
physiologic, functional, anatomic, and histologic outcomes seen in clinical AKI, is rapidly repeatable, and offers all of the significant advantages of a murine surgical 
model, including access to genetic manipulative techniques, low cost relative to large animals, and ease of use. Our group has developed extensive experience 
with use of this model to assess a number of organ-specific outcomes in AKI.14,15

A powerful model for perioperative and critical care related acute kidney injury is presented. Using whole body hypoperfusion induced by cardiac arrest it is possible to nearly replicate the histologic and functional changes of clinical AKI.

Acute Kidney Injury (AKI) is a common, highly lethal, complication of critical illness which has a high mortality1-4 and which is most 
frequently caused ...

Renal Ischaemia Reperfusion Injury: A Mouse Model of Injury and Regeneration

Renal ischaemia reperfusion injury (IRI) is a common cause of acute kidney injury (AKI) in patients and occlusion of renal blood flow is unavoidable during renal transplantation. Experimental models that accurately and reproducibly recapitulate renal IRI are crucial in dissecting the pathophysiology of AKI and the development of novel therapeutic agents. Presented here is a mouse model of renal IRI that results in reproducible AKI. This is achieved by a midline laparotomy approach for the surgery with one incision allowing both a right nephrectomy that provides control tissue and clamping of the left renal pedicle to induce ischaemia of the left kidney. By careful monitoring of the clamp position and body temperature during the period of ischaemia this model achieves reproducible functional and structural injury. Mice sacrificed 24 hr&#160;following surgery demonstrate loss of renal function with elevation of the serum or plasma creatinine level as well as structural kidney damage with acute tubular necrosis evident. Renal function improves and the acute tissue injury resolves during the course of 7 days following renal IRI such that this model may be used to study renal regeneration. This model of renal IRI has been utilized to study the molecular and cellular pathophysiology of AKI as well as analysis of the subsequent renal regeneration.

The mouse model of renal ischaemia reperfusion injury described here comprises of a right nephrectomy that provides control tissue and clamping of the left renal pedicle to induce ischaemia that results in acute kidney injury. This model uses a midline laparotomy approach with all steps performed via one incision.

Renal ischaemia reperfusion injury (IRI) is a common cause of acute kidney injury (AKI) in patients and occlusion of renal blood flow is unavoidable ...

Induction and Assessment of Ischemia-reperfusion Injury in Langendorff-perfused Rat Hearts

The biochemical events surrounding ischemia reperfusion injury in the acute setting are of great importance to furthering novel treatment options for myocardial infarction and cardiac complications of thoracic surgery. The ability of certain drugs to precondition the myocardium against ischemia reperfusion injury has led to multiple clinical trials, with little success. The isolated heart model allows acute observation of the functional effects of ischemia reperfusion injury in real time, including the effects of various pharmacological interventions administered at any time-point before or within the ischemia-reperfusion injury window. Since brief periods of ischemia can precondition the heart against ischemic injury, in situ aortic cannulation is performed to allow for functional assessment of non-preconditioned myocardium. A saline filled balloon is placed into the left ventricle to allow for real-time measurement of pressure generation. Ischemic injury is simulated by the cessation of perfusion buffer flow, followed by reperfusion. The duration of both ischemia and reperfusion can be modulated to examine biochemical events at any given time-point. Although the Langendorff isolated heart model does not allow for the consideration of systemic events affecting ischemia and reperfusion, it is an excellent model for the examination of acute functional and biochemical events within the window of ischemia reperfusion injury as well as the effect of pharmacological intervention on cardiac pre- and postconditioning. The goal of this protocol is to demonstrate how to perform in situ aortic cannulation and heart excision followed by ischemia/reperfusion injury in the Langendorff model.

The isolated rat heart is an enduring model for ischemia reperfusion injury. Here, we describe the process of harvesting the beating heart from a rat via in situ aortic cannulation, Langendorff perfusion of the heart, simulated ischemia-reperfusion injury, and infarct staining to confirm the extent of ischemic insult.

The biochemical events surrounding ischemia reperfusion injury in the acute setting are of great importance to furthering novel treatment options for ...

Murine Model of Intestinal Ischemia-reperfusion Injury

Intestinal ischemia is a life-threatening condition associated with a broad range of clinical conditions including atherosclerosis, thrombosis, hypotension, necrotizing enterocolitis, bowel transplantation, trauma and chronic inflammation. Intestinal ischemia-reperfusion (IR) injury is a consequence of acute mesenteric ischemia, caused by inadequate blood flow through the mesenteric vessels, resulting in intestinal damage. Reperfusion following ischemia can further exacerbate damage of the intestine. The mechanisms of IR injury are complex and poorly understood. Therefore, experimental small animal models are critical for understanding the pathophysiology of IR injury and the development of novel therapies.
Here we describe a mouse model of acute intestinal IR injury that provides reproducible injury of the small intestine without mortality. This is achieved by inducing ischemia in the region of the distal ileum by temporally occluding the peripheral and terminal collateral branches of the superior mesenteric artery for 60 min using microvascular clips. Reperfusion for 1 hr, or 2 hr after injury results in reproducible injury of the intestine examined by histological analysis. Proper position of the microvascular clips is critical for the procedure. Therefore the video clip provides a detailed visual step-by-step description of this technique. This model of intestinal IR injury can be utilized to study the cellular and molecular mechanisms of injury and regeneration.

Here we describe the detailed procedure of intestinal ischemia-reperfusion in mice which results in reproducible injury without mortality to encourage the standardization of this technique across the field. This model of intestinal ischemia-reperfusion injury can be utilized to study the cellular and molecular mechanisms of injury and regeneration.

Intestinal ischemia is a life-threatening condition associated with a broad range of clinical conditions including atherosclerosis, thrombosis, ...

Evaluation of Coronary Flow Reserve After Myocardial Ischemia Reperfusion in Rats

Coronary artery disease is the leading cause of death worldwide. After an acute myocardial infarction, early and successful myocardial intervention via recanalization of the coronary artery is the most effective strategy for reducing the size of ischemic myocardium. The coronary microvasculature cannot be visualized and imaged&#160;in vivo, but there are several invasive and noninvasive techniques that can be used to assess parameters which depend directly on coronary microvascular function. The endothelial function after ischemia reperfusion can be assessed also at the level of the coronary circulation via the coronary flow reserve (CFR).&#160;In this study, peak velocity of left anterior descending (LAD) coronary arteries was measured in rats in vivo via Transthoracic Doppler Echocardiography during resting and stress challenge (induced by Dobutamine). A normal heart can increase its coronary blood flow up to four times above the resting values during stress induction. Following ischemia reperfusion, we found a significantly diminished CFR, which can be used as a marker of coronary microvascular dysfunction. CFR has opened a window on the importance of microvascular dysfunction and has been shown to predict cardiovascular risk independent of whether the severe obstructive disease is present.

Coronary flow reserve (CFR), is defined as the ratio of maximal coronary blood flow to the resting coronary blood flow. We present a protocol for evaluating CFR in rats via ultrasound, which offers the opportunity to predict cardiovascular risk factors in the absence of obstructive coronary disease.

Coronary artery disease is the leading cause of death worldwide. After an acute myocardial infarction, early and successful myocardial intervention via ...

An Effective Mouse Model of Unilateral Renal Ischemia-Reperfusion Injury

Ischemia-reperfusion injury (IRI) is the leading cause of acute renal failure and is a significant contributor to delayed graft function. Animal models are the only available resources that mimic the complexities of the IRI-associated damage encountered in vivo. This paper describes an effective mouse model of unilateral renal IRI that delivers highly reproducible data. Ischemia is induced by occluding the right renal pedicle for 30 min followed by reperfusion. In addition to the surgical procedure, a sequential overview of the expected physiological and histopathological changes following renal IRI will be provided by comparing data from seven different reperfusion times (4 h, 8 h, 16 h, 1 day, 2 days, 4 days, and 7 days). Critical data for planning experiments ahead, such as mean surgical time, average anesthetic consumption, and body weight changes over time, will be shared. This work will help researchers implement a reliable renal IRI model and select the appropriate reperfusion time that aligns with their intended investigative goals.

Renal ischemia-reperfusion injury is associated with high morbidity and mortality in hospitalized patients. Here, we present a simple and effective mouse model of unilateral renal ischemia-reperfusion injury and provide a sequential overview of representative pathological changes observed in the kidney.

Ischemia-reperfusion injury (IRI) is the leading cause of acute renal failure and is a significant contributor to delayed graft function. Animal models ...

The Mouse Isolated Perfused Kidney Technique

The mouse isolated perfused kidney (MIPK) is a technique for keeping a mouse kidney under ex vivo conditions perfused and functional for 1 hr. This is a prerequisite for studying the physiology of the isolated organ and for many innovative applications that may be possible in the future, including perfusion decellularization for kidney bioengineering or the administration of anti-rejection or genome-editing drugs in high doses to prime the kidney for transplantation. During the time of the perfusion, the kidney can be manipulated, renal function can be assessed, and various pharmaceuticals administered. After the procedure, the kidney can be transplanted or processed for molecular biology, biochemical analysis, or microscopy.
This paper describes the perfusate and the surgical technique needed for the ex vivo perfusion of mouse kidneys. Details of the perfusion apparatus are given and data are presented showing the viability of the kidney&#39;s preparation: renal blood flow, vascular resistance, and urine data as functional, transmission electron micrographs of different nephron segments as morphological readouts, and western blots of transport proteins of different nephron segments as molecular readout.

The mouse isolated perfused kidney (MIPK) is a technique for keeping a mouse kidney under ex vivo conditions perfused and functional for 1 hr. The buffers and surgical technique are described in detail.

The mouse isolated perfused kidney (MIPK) is a technique for keeping a mouse kidney under ex vivo conditions perfused and functional for 1 hr. This is a ...

Biology

Technical Refinement of a Bilateral Renal Ischemia-Reperfusion Mouse Model for Acute Kidney Injury Research

Cardiac arrest poses a large public health burden. Acute kidney injury (AKI) is an adverse marker in survivors of cardiac arrest following the return of spontaneous circulation (ROSC) after successful cardiopulmonary resuscitation. Conversely, recovery of kidney function from AKI is a predictor of favorable neurological outcomes and hospital discharge. However, an effective intervention to prevent kidney damage caused by cardiac arrest after ROSC is lacking, suggesting that additional therapeutic strategies are required. Renal hypoperfusion and reperfusion are two pathophysiological mechanisms that cause AKI after cardiac arrest. Animal models of ischemia-reperfusion-induced AKI (IR-AKI) of both kidneys are comparable with patients with AKI following ROSC in a clinical setting. However, IR-AKI of both kidneys is technically challenging to analyze because the model is associated with high mortality and wide variation in kidney damage, which may affect the analysis. Lightweight mice were chosen, placed under general anesthesia with isoflurane, subjected to surgery with a dorsolateral approach, and their body temperature maintained during operation, thereby reducing tissue damage and establishing a reproducible acute renal IR-AKI research protocol.

This study established a protocol focusing on the technical refinement of a mouse model of bilateral renal ischemia-reperfusion for acute kidney injury research.

Cardiac arrest poses a large public health burden. Acute kidney injury (AKI) is an adverse marker in survivors of cardiac arrest following the return of ...

Developing Murine Acute Kidney Injury Model Using Bilateral Ischemia-Reperfusion

Bilateral Renal Ischemia-Reperfusion Model for Acute Kidney Injury in Mice

Acute kidney injury (AKI) is defined as a rapid decline in renal function, in which persistent kidney dysfunction gradually progresses to chronic kidney disease (CKD) due to the irreversible loss of nephrons and their maladaptive repair. In recent years, the incidence of AKI has been increasing concerning diverse etiologies, including volume depletion, sepsis, nephrotoxicity, muscle injury, and major trauma, in which ischemia-reperfusion injury (IRI)&#160;accounts for most episodes. Development of the IRI model in mice is induced by surgical clamping of the renal pedicles, which provides powerful and controllable tools for preclinical models of AKI. Importantly, the IRI model is deployed at different stages of the AKI development, especially in the processes of AKI to CKD. Despite the IRI model being widely practiced in many laboratories, a series of variables still influence the results of this model. Here, we describe the procedure of IRI model development to provide a repeatable and reliable method for researchers to explore the underlying pathogenesis in the development of AKI and the progression of AKI to CKD.

The ischemia-reperfusion injury (IRI) model can be used at different stages of acute kidney injury (AKI) development, especially during AKI to chronic kidney disease (CKD) progression. Here, we describe the procedure for IRI model development in mice via a trans-abdominal approach, clamping renal pedicles via a vascular clip to induce ischemic injury.

Acute kidney injury (AKI) is defined as a rapid decline in renal function, in which persistent kidney dysfunction gradually progresses to chronic kidney ...

Unilateral Ureteral Obstruction Model for Investigating Kidney Interstitial Fibrosis

Kidney fibrosis is the final pathological outcome of progressive chronic kidney disease (CKD). The unilateral ureteral obstruction (UUO) model is widely used to elucidate the molecular and cellular mechanisms underlying kidney interstitial fibrosis and to identify potential therapeutic targets. This model is established in mice through surgical ligation of a unilateral ureter, a procedure that is relatively straightforward and easy to perform. However, the UUO mouse model is known to exhibit significant variability and inconsistency, influenced by factors such as mouse strain, age, sex, anesthesia type, duration of surgery, body temperature during the procedure, the operator's surgical skills, feeding conditions, and the overall health status of the mice. Variations in surgical techniques, suture placement, and the duration of obstruction contribute to the variability in outcomes. Additionally, inconsistent sampling of obstructed kidneys further increases variability in the assessment of kidney fibrosis. This study outlines the process of developing the UUO mouse model and evaluating interstitial fibrosis, discusses the technical challenges contributing to the model's unpredictability, and proposes potential solutions. These insights aim to establish a more standardized and universally applicable approach for investigating kidney fibrosis.

This protocol describes a method for inducing unilateral ureteral obstruction (UUO) in mice to study the progression of tissue fibrosis in obstructive nephropathy. It includes surgical procedures, post-operative care, and methods for fibrosis assessment.

Kidney fibrosis is the final pathological outcome of progressive chronic kidney disease (CKD). The unilateral ureteral obstruction (UUO) model is widely ...