Name: surgical models of gastroesophageal reflux with mice
Uploaded: 2015-08-25T15:00:00
Description: Watch this Scientific Journal Video about Surgical Models of Gastroesophageal Reflux with Mice at JoVE.com

We are supported by research grants from the National Natural Science Foundation of China (NO. 81400590), National Institutes of Health (U54 CA156735) and Takeda Pharmaceutical Company Ltd. (MA-NC-D-156).

All the animal experiments have been approved by the Institutional Animal Care and Use Committee.
1. Mouse Preparation
<ol>
	<li>Use mice over ~20 g in body weight or above ~6 weeks in age for surgery.</li>
	<li>Before surgery, give mice a laboratory chow and water ad libitum and maintain on a 12:12 hr light-dark cycle.</li>
	<li>Shave the surgical area with a hair clipper. Anesthetize mice by intraperitoneal injection of 80 mg/kg ketamine and 12 mg/kg xylazine. This dose puts mice ...

<ol>
	<li>Kandulski, A., Malfertheiner, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gastroesophageal+reflux+disease--from+reflux+episodes+to+mucosal+inflammation.">Gastroesophageal reflux disease--from reflux episodes to mucosal inflammation.</a> Nat Rev Gastroenterol Hepatol. 9 (1), 15-22 (2012).</li><li>Orlando, R. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+integrity+of+the+esophageal+mucosa.+Balance+between+offensive+and+defensive+mechanisms.">The integrity of the esophageal mucosa. Balance between offensive and defensive mechanisms.</a> Best Pract Res Clin Gastroenterol. 24 (6), 873-882 (2010).</li><li>Stairs, D. B., Kong, J., Lynch, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cdx+genes,+inflammation,+and+the+pathogenesis+of+intestinal+metaplasia.">Cdx genes, inflammation, and the pathogenesis of intestinal metaplasia.</a> Prog Mol Biol Transl Sci. 96, 231-270 (2010).</li><li>Spechler, S. J., Fitzgerald, R. C., Prasad, G. A., History Wang, K. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=molecular+mechanisms,+and+endoscopic+treatment+of+Barrett's+esophagus.">molecular mechanisms, and endoscopic treatment of Barrett's esophagus.</a> Gastroenterology. 138 (3), 854-869 (2010).</li><li>Fang, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellular+origins+and+molecular+mechanisms+of+Barrett's+esophagus+and+esophageal+adenocarcinoma.">Cellular origins and molecular mechanisms of Barrett's esophagus and esophageal adenocarcinoma.</a> Ann N Y Acad Sci. 1300, 187-199 (2013).</li><li>Garman, K. S., Orlando, R. C., Chen, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Review:+Experimental+models+for+Barrett's+esophagus+and+esophageal+adenocarcinoma.">Review: Experimental models for Barrett's esophagus and esophageal adenocarcinoma.</a> Am J Physiol Gastrointest Liver Physiol. 302 (11), G1231-G1243 (2012).</li><li>Baruah, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Translational+research+on+Barrett's+esophagus.">Translational research on Barrett's esophagus.</a> Ann N Y Acad Sci. 1325, 170-186 (2014).</li><li>Lechpammer, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flavopiridol+reduces+malignant+transformation+of+the+esophageal+mucosa+in+p27+knockout+mice.">Flavopiridol reduces malignant transformation of the esophageal mucosa in p27 knockout mice.</a> Oncogene. 24 (10), 1683-1688 (2005).</li><li>Hao, J., Liu, B., Yang, C. S., Chen, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gastroesophageal+reflux+leads+to+esophageal+cancer+in+a+surgical+model+with+mice.">Gastroesophageal reflux leads to esophageal cancer in a surgical model with mice.</a> BMC Gastroenterol. 9, 59 (2009).</li><li>Mari, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+pSMAD/CDX2+complex+is+essential+for+the+intestinalization+of+epithelial+metaplasia.">A pSMAD/CDX2 complex is essential for the intestinalization of epithelial metaplasia.</a> Cell Rep. 7 (4), 1197-1210 (2014).</li><li>Fang, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gastroesophageal+reflux+activates+the+NF-kappaB+pathway+and+impairs+esophageal+barrier+function+in+mice.">Gastroesophageal reflux activates the NF-kappaB pathway and impairs esophageal barrier function in mice.</a> Am J Physiol Gastrointest Liver Physiol. 305 (1), G58-G65 (2013).</li><li>Chen, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nrf2+deficiency+impairs+the+barrier+function+of+mouse+oesophageal+epithelium.">Nrf2 deficiency impairs the barrier function of mouse oesophageal epithelium.</a> Gut. 63 (5), 711-719 (2014).</li></ol>

Various surgical models have been established to mimic gastric, duodenal and mixed reflux in rodents. These three procedures described here are suitable for long-term experiments with reasonable rates of postoperative survival. A researcher with surgical experience should be able to grasp the technique after a short period of practice.
Bleeding may result from intraperitoneal injection of anesthetics before surgery, laceration of the liver during separation of the connective tissues between th...

Gastroesophageal reflux disease (GERD) is a chronic disorder caused by the prolonged exposure of distal esophagus to gastric or gastroduodenal contents1. Prolonged exposure to these noxious refluxates impairs the intrinsic defenses within the esophageal epithelium and thus results in esophagitis2. Barrett&#8217;s esophagus arises in the setting of chronic reflux, and is a premalignant lesion with increased risk of esophageal adenocarcinoma3,4. Despite the clinical importance, the mechanisms of GERD, Barrett&#8217;s esophagus and adenocarcinoma have not been well understood. 
Animal models are essential for research on etiology, pathology, molecular mechanisms, prevention and treatment of human diseases. Up to date, various animal models of GERD, Barrett&#8217;s esophagus and adenocarcinoma have been developed using model animals5,6. Mouse esophagus is lined with stratified squamous epithelium which is histologically similar to that in human esophagus. Although a mouse esophagus is different from human esophagus in terms of keratinization and the absence of submucosal glands, the mouse is still an appealing model animal because of its relatively low cost of maintenance and its potential of sophisticated genetic modifications. Two approaches are commonly used to model GERD, Barrett&#8217;s esophagus and adenocarcinoma in mice: reflux surgery and genetic modification. Reflux surgery is the best way to induce reflux and genetic modifications mimics molecular alterations5,7. Reflux surgery can be combined with genetic modifications to further understand disease mechanisms8. 
Many surgical procedures have been reported by us and others6,9: (1) gastric reflux: pyloric ligation, pyloric constriction with forestomach ligation, Wendel cardioplasty, and esophagogastric anastomosis; (2) mixed reflux: esophagogastroduodenal anastomosis, esophagoduodenostomy (or esophagojejunostomy); (3) duodenal reflux: esophagogastroduodenal anastomosis plus gastrectomy; (4) reflux of chemical components: bilious reflux, pancreatic reflux, esophageal perfusion; and (5) esophageal transplantation5. Recently a microsurgical mouse model was reported to produce jejunal reflux via an esophagojejunostomy with magnets10. These surgical models have advantages over in vitro cell culture or organotypic culture models. In vitro, esophageal cells cannot tolerate a medium with high acidity or high concentrations of bile acids. Unconjugated bile acids which are commonly used to produce changes in esophageal epithelial cells in vitro are usually not present in the duodenal refluxate in vivo. Thus conclusions drawn from such in vitro studies should be taken with caution.
Surgery on the mouse esophagus remains a technical challenge because of its small size. A low rate of postoperative survival does not allow experiments which require certain sample size to reach statistically sound conclusions. In the past we have successfully developed and characterized surgical models of gastric reflux, mixed reflux, duodenal reflux with mice in long-term experiments9,11,12. We have also provided consultation to several other groups in their mouse surgery. Herein, we describe three surgical procedures in mice in order to help the community to establish these models in their labs.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Instruments</td>
			<td>Source</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Dumont #1 Forceps Dumostar Tip&#160;</td>
			<td>Roboz Surgical Instrument Co. (Gaithersburg, MD)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Micro Clip Applying Forceps 5.5&#34;</td>
			<td>Roboz Surgical Instrument Co. (Gaithersburg, MD)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Bonn Scissors 3.5&#34; Straight 15mm Sharp/Sharp Tungsten Carbide Blades</td>
			<td>Roboz Surgical Instrument Co. (Gaithersburg, MD)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Operating Scissors 5.5&#34; Straight Sharp/Sharp SureCut</td>
			<td>Roboz Surgical Instrument Co. (Gaithersburg, MD)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>4-0 Silk Black Braid 100 Yard Spool</td>
			<td>Roboz Surgical Instrument Co. (Gaithersburg, MD)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Surgeon&#39;s Needle 1/2 Circle Cutting Edge Size 12 (25 mm Chord Length) Pack 12</td>
			<td>Roboz Surgical Instrument Co. (Gaithersburg, MD)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Halsey Needle Holder 5&#34; Smooth</td>
			<td>Roboz Surgical Instrument Co. (Gaithersburg, MD)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Micro Needle Holder 5.125&#34; Curved Lock .6mm</td>
			<td>Roboz Surgical Instrument Co. (Gaithersburg, MD)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Reflex 9mm Wound Clip Applier</td>
			<td>Roboz Surgical Instrument Co. (Gaithersburg, MD)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Reflex 9mm Wound Clips Box Of 100</td>
			<td>Roboz Surgical Instrument Co. (Gaithersburg, MD)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>PRONOVA Poly (hexafluoropropylene-VDF) Suture 8-0</td>
			<td>Ethicon US, LLC</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Reagents</td>
			<td>Source</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ringer&#39;s solution</td>
			<td>Henry Schein, Inc.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>ketamine</td>
			<td>Henry Schein, Inc.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>xylazine</td>
			<td>Henry Schein, Inc.</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

surgical models of gastroesophageal reflux with mice

Multiple surgical procedures have been reported to induce gastroesophageal reflux in animals. Herein, we report three surgical models with mice aiming to induce reflux of gastric contents, duodenal contents or mixed contents. Surgical procedures and general principles have been described in detail. A researcher with surgical experience should be able to grasp the technique after a short period of practice. After surgery, most mice can survive and develop reflux esophagitis similar to that in humans. However, it should be noted that histological differences between mouse and human esophagus are the inherent limitations of these surgical models. If used for research on Barrett&#8217;s esophagus and adenocarcinoma, these procedures may need to be combined with genetic modifications.

Most mice (&#62;95%) can survive the surgery. During the perioperative period, the leading causes of death include overdose of anesthetics, bleeding and unknown reasons.
Four weeks after surgery, &#62;90% mice with gastric reflux or mixed reflux and &#62;80% mice with duodenal reflux can survive. During this period, mice primarily die of esophageal stricture and inability to eat. These mice show signs of severe stress (hunched posture, inactivity, vomiting, sunken eyes, vocalization, etc.<...

Watch this Scientific Journal Video about Surgical Models of Gastroesophageal Reflux with Mice at JoVE.com

Surgical Models of Gastroesophageal Reflux with Mice

This article demonstrates surgical procedures of gastroesophageal reflux with mice. These models are useful tools for research on mechanisms and treatment of gastroesophageal reflux disease and potentially Barrett&#8217;s esophagus and esophageal adenocarcinoma.

Multiple surgical procedures have been reported to induce gastroesophageal reflux in animals. Herein, we report three surgical models with mice aiming to ...

surgical-models-of-gastroesophageal-reflux-with-mice

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Medicine

Surgical Management of Meatal Stenosis with Meatoplasty

Meatal stenosis is a common urologic complication after circumcision. Children present to their primary care physicians with complaints of deviated urinary stream, difficult-to-aim, painful urination, and urinary frequency. Clinical exam reveals a pinpoint meatus and if the child is asked to urinate, he will usually have an upward, thin, occasionally forceful urinary stream with incomplete bladder emptying. The mainstay of management is meatoplasty (reconstruction of the distal urethra /meatus). This educational video will demonstrate how this is performed.

Meatoplasty, surgical management of meatal stenosis.

Meatal stenosis is a common urologic complication after circumcision.  Children present to their primary care physicians with complaints of deviated ...

Implantation of Radiotelemetry Transmitters Yielding Data on ECG, Heart Rate, Core Body Temperature and Activity in Free-moving Laboratory Mice

The laboratory mouse is the animal species of choice for most biomedical research, in both the academic sphere and the pharmaceutical industry. Mice are a manageable size and relatively easy to house. These factors, together with the availability of a wealth of spontaneous and experimentally induced mutants, make laboratory mice ideally suited to a wide variety of research areas.
In cardiovascular, pharmacological and toxicological research, accurate measurement of parameters relating to the circulatory system of laboratory animals is often required. Determination of heart rate, heart rate variability, and duration of PQ and QT intervals are based on electrocardiogram (ECG) recordings. However, obtaining reliable ECG curves as well as physiological data such as core body temperature in mice can be difficult using conventional measurement techniques, which require connecting sensors and lead wires to a restrained, tethered, or even anaesthetized animal. Data obtained in this fashion must be interpreted with caution, as it is well known that restraining and anesthesia can have a major artifactual influence on physiological parameters1, 2.
Radiotelemetry enables data to be collected from conscious and untethered animals. Measurements can be conducted even in freely moving animals, and without requiring the investigator to be in the proximity of the animal. Thus, known sources of artifacts are avoided, and accurate and reliable measurements are assured. This methodology also reduces interanimal variability, thus reducing the number of animals used, rendering this technology the most humane method of monitoring physiological parameters in laboratory animals3, 4. Constant advancements in data acquisition technology and implant miniaturization mean that it is now possible to record physiological parameters and locomotor activity continuously and in realtime over longer periods such as hours, days or even weeks3, 5.
Here, we describe a surgical technique for implantation of a commercially available telemetry transmitter used for continuous measurements of core body temperature, locomotor activity and biopotential (i.e. onelead ECG), from which heart rate, heart rate variability, and PQ and QT intervals can be established in freeroaming, untethered mice. We also present pre-operative procedures and protocols for post-operative intensive care and pain treatment that improve recovery, well-being and survival rates in implanted mice5, 6.

A surgical technique for implantation of commercially available telemetry transmitters used for continuous measurement of biopotential (one-lead ECG), heart rate, core body temperature and locomotor activity in freely moving mice is shown. Recommendations and protocols for post-operative care and pain relief, improving recovery, well being and survival rate are also presented.

The laboratory mouse is the animal species of choice for most biomedical research, in both the academic sphere and the pharmaceutical industry. Mice are a ...

Protocols for Assessing Radiofrequency Interactions with Gold Nanoparticles and Biological Systems for Non-invasive Hyperthermia Cancer Therapy

Cancer therapies which are less toxic and invasive than their existing counterparts are highly desirable. The use of RF electric-fields that penetrate deep into the body, causing minimal toxicity, are currently being studied as a viable means of non-invasive cancer therapy. It is envisioned that the interactions of RF energy with internalized nanoparticles (NPs) can liberate heat which can then cause overheating (hyperthermia) of the cell, ultimately ending in cell necrosis.
In the case of non-biological systems, we present detailed protocols relating to quantifying the heat liberated by highly-concentrated NP colloids. For biological systems, in the case of in vitro experiments, we describe the techniques and conditions which must be adhered to in order to effectively expose cancer cells to RF energy without bulk media heating artifacts significantly obscuring the data. Finally, we give a detailed methodology for in vivo mouse models with ectopic hepatic cancer tumors.

We describe the protocols used to investigate the interactions of 13.56 MHz radiofrequency (RF) electric-fields with gold nanoparticle colloids in both non-biological and biological systems (in vitro/vivo). These interactions are being investigated for applications in cancer therapy.

Cancer therapies  which are less toxic and invasive than their existing counterparts are highly  desirable. The use of RF electric-fields that penetrate ...

Inducing Myointimal Hyperplasia Versus Atherosclerosis in Mice: An Introduction of Two Valid Models

Various in vivo laboratory rodent models for the induction of artery stenosis have been established to mimic diseases that include arterial plaque formation and stenosis, as observed for example in ischemic heart disease. Two highly reproducible mouse models&#160;&#8211;&#160;both resulting in artery stenosis but each underlying a different pathway of development&#160;&#8211; are introduced here. The models represent the two most common causes of artery stenosis; namely one mouse model for each myointimal hyperplasia, and atherosclerosis are shown. To induce myointimal hyperplasia, a balloon catheter injury of the abdominal aorta is performed. For the development of atherosclerotic plaque, the ApoE -/- mouse model in combination with western fatty diet is used. Different model-adapted options for the measurement and evaluation of the results are named and described in this manuscript. The introduction and comparison of these two models provides information for scientists to choose the appropriate artery stenosis model in accordance to the scientific question asked.

This video shows two models of intimal plaque development in murine arteries and emphasizes the differences in myointimal hyperplasia and atherosclerosis.

Various in vivo laboratory rodent models for the induction of artery stenosis have been established to mimic diseases that include arterial plaque ...

Minimal Invasive Surgical Procedure of Inducing Myocardial Infarction in Mice

Myocardial infarction still remains the main cause of death in western countries, despite considerable progress in the stent development area in the last decades. For clarification of the underlying mechanisms and the development of new therapeutic strategies, the availability of valid animal models are mandatory. Since we need new insights into pathomechanisms of cardiovascular diseases under in vivo conditions to combat myocardial infarction, the validity of the animal model is a crucial aspect. However, protection of animals are highly relevant in this context. Therefore, we establish a minimally invasive and simple model of myocardial infarction in mice, which assures a high reproducibility and survival rate of animals. Thus, this models fulfils the requirements of the 3R principle (Replacement, Refinement and Reduction) for animal experiments and assure the scientific information needed for further developing of therapeutical strategies for cardiovascular diseases.

A highly reproducible model for myocardial infarction in mice with minimal invasive manipulations is described. The model can be easily performed, resulting in a high reproducibility and survival rate. Thus, the described model will reduce the number of required animals as requested by the 3R principle (Replacement, Refinement and Reduction).

Myocardial infarction still remains the main cause of death in western countries, despite considerable progress in the stent development area in the last ...

Using Saccadometry with Deep Brain Stimulation to Study Normal and Pathological Brain Function

The oculomotor system involves a large number of brain areas including parts of the basal ganglia, and various neurodegenerative diseases including Parkinson's and Huntington's can disrupt it. People with Parkinson's disease, for example, tend to have increased saccadic latencies. Consequently, the quantitative measurement of saccadic eye movements has received considerable attention as a potential biomarker for neurodegenerative conditions. A lot more can be learned about the brain in both health and disease by observing what happens to eye movements when the function of specific brain areas is perturbed. Deep brain stimulation is a surgical intervention used for the management of a range of neurological conditions including Parkinson's disease, in which stimulating electrodes are placed in specific brain areas including several sites in the basal ganglia. Eye movement measurements can then be made with the stimulator systems both off and on and the results compared. With suitable experimental design, this approach can be used to study the pathophysiology of the disease being treated, the mechanism by which DBS exerts it beneficial effects, and even aspects of normal neurophysiology.

This paper describes the use of quantitative measurement of eye movements in conjunction with stimulation of focal areas of the deep brain in order to study physiology, pathophysiology, and the mechanisms of deep brain stimulation.

The oculomotor system involves a large number of brain areas including parts of the basal ganglia, and various neurodegenerative diseases including ...

Cutaneous Surgical Denervation:  A Method for Testing the Requirement for Nerves in Mouse Models of Skin Disease

Cutaneous somatosensory nerves function to detect diverse stimuli that act upon the skin. In addition to their established sensory roles, recent studies have suggested that nerves may also modulate skin disorders including atopic dermatitis, psoriasis and cancer. Here, we describe protocols for testing the requirement for nerves in maintaining a cutaneous mechanosensory organ, the touch dome (TD). Specifically, we discuss methods for genetically labeling, harvesting and visualizing TDs by whole-mount staining, and for performing unilateral surgical denervation on mouse dorsal back skin. Together, these approaches can be used to directly compare TD morphology and gene expression in denervated as well as sham-operated skin from the same animal. These methods can also be readily adapted to examine the requirement for nerves in mouse models of skin pathology. Finally, the ability to repeatedly sample the skin provides an opportunity to monitor disease progression at different stages and times after initiation.

This article includes detailed protocols for genetic labeling of mouse skin, surgical denervation, skin biopsy and visualizing labeled epithelia by whole-mount &#946;-galactosidase staining. These methods can be used to test the requirement for nerves in mouse models of normal and pathological skin.

Cutaneous somatosensory nerves function to detect diverse stimuli that act upon the skin. In addition to their established sensory roles, recent studies ...

Intravital Microscopy of Tumor-associated Vasculature Using Advanced Dorsal Skinfold Window Chambers on Transgenic Fluorescent Mice

Tumor and tumor vessel development, as well as tumor response to therapeutics, are highly dynamic biological processes. Histology provides static information and is often not sufficient for a correct interpretation. Intravital evaluation, in which a process is followed in time, provides extra and often unexpected information. With the creation of transgenic animals expressing cell-specific markers and live cell tracers, improvements to imaging equipment, and the development of several imaging chambers, intravital microscopy has become an important tool to better understand biological processes. This paper describes an experimental design for the investigation of tumor vessel development and of therapeutic effects in a spatial and temporal manner. Using this setup, the stage of vessel development, tip cell and lumen formation, blood flow, extravasation, an established vascular bed, and vascular destruction can be visualized and followed. Furthermore, therapeutic effects, intratumoral fate, and the localization of chemotherapeutic compounds can also be followed.

This protocol describes the intravital imaging of transgenic mice expressing cell-specific fluorescent markers. Intravital imaging provides a non-invasive method for high-resolution observations in living animals using implantable windows through which the microscopic visualization of processes is possible. This method is especially useful to study longitudinal processes.

Tumor and tumor vessel development, as well as tumor response to therapeutics, are highly dynamic biological processes. Histology provides static ...

Using In Vitro Live-cell Imaging to Explore Chemotherapeutics Delivered by Lipid-based Nanoparticles

Conventional imaging techniques can provide detailed information about cellular processes. However, this information is based on static images in an otherwise dynamic system, and successive phases are easily overlooked or misinterpreted. Live-cell imaging and time-lapse microscopy, in which living cells can be followed for hours or even days in a more or less continuous fashion, are therefore very informative. The protocol described here allows for the investigation of the fate of chemotherapeutic nanoparticles after the delivery of doxorubicin (dox) in living cells. Dox is an intercalating agent that must be released from its nanocarrier to become biologically active. In spite of its clinical registration for more than two decades, its uptake, breakdown, and drug release are still not fully understood. This article explores the hypothesis that lipid-based nanoparticles are taken up by the tumor cells and are slowly degraded. Released dox is then translocated to the nucleus. To prevent fixation artifacts, live-cell imaging and time-lapse microscopy, described in this experimental procedure, can be applied.

Using In Vitro Live-cell Imaging to Explore Chemotherapeutics Delivered by Lipid-based Nanoparticles

Live-cell imaging is a powerful tool to visualize dynamic processes. The examination of fixed cells provides only static pictures, which can lead to misinterpretation and confusion about the process. This work presents a method to study uptake, drug release, and intracellular localization of liposomal nanoparticles in living cells.

Conventional imaging techniques can provide detailed information about cellular processes. However, this information is based on static images in an ...

Sleeve Gastrectomy in Mice using Surgical Clips

The number of people who are overweight and obese is continually increasing both in the adult and adolescent populations. This coincides with the increased universal phenomenon of type 2 diabetes (T2D) and other metabolic problems. Bariatric surgery, such as SG, is currently one of the most effective and commonly used long-term treatment for obesity and T2D, but the association between them is not completely explored yet. The mechanisms underlying the outcomes seen after bariatric surgery in humans can be investigated based on preclinical animal studies. The SG reduces body weight, glucose levels and many metabolic parameters, and is easy to perform with a low incidence of complications. The goal of this work is to provide a simple method and an uncomplicated preclinical model of bariatric surgery in animals for researchers.

The prevalence of diabetes and obesity is continuously increasing worldwide. The mechanisms between diabetes, obesity and their associated mortality and co-morbidities need to be further investigated. Here, we present a protocol for sleeve gastrectomy (SG) in animals as an uncomplicated preclinical model of bariatric surgery.