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 border="1">
	<tbody>
		<tr>
			<td>Drug or solution</td>
			<td>Company</td>
			<td>Catalogue number</td>
			<td>Comments</td>
		</tr>
		<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 &mu;g/g every 8-12 hr. Make up a 1:5 dilution in sterile normal saline preoperatively and give 2.5-5 &mu;l/g of the diluted solution.</td>
		</tr>
		<tr>
			<td>Ophthalmic ointment</td>
			<td>Dechra</td>
			<td>NDC 17033-211-38</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Betadine swab sticks</td>
			<td>Purdue Products L.P.</td>
			<td>NDC 67618-153-01</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Nolvasan Surgical Scrub</td>
			<td>Pfizer Animal Care</td>
			<td>300253</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>Table 2. Drugs and solutions for I/R surgery.</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 &deg;C 1 hr prior surgery</td>
		</tr>
		<tr>
			<td>15" W x 24" 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>&nbsp;</td>
		</tr>
		<tr>
			<td>Tape</td>
			<td>Durapore</td>
			<td>1538-0</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>1 ml Syringe</td>
			<td>EXELint</td>
			<td>26044</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Sterile cotton tipped applicators</td>
			<td>Kendall</td>
			<td>8884541300</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Absorbent BenchPad</td>
			<td>VWR</td>
			<td>56617-014</td>
			<td>&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'' x 2'' Gauze Pads</td>
			<td>Medi-First</td>
			<td>60673</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Sterile gloves</td>
			<td>Cardinal Health</td>
			<td>2D7251</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>Table 3. Equipment and instruments for I/R surgery.</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...

Watch this Scientific Journal Video about Ischemia-reperfusion Model of Acute Kidney Injury and Post Injury Fibrosis in Mice at JoVE.com

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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39.3K 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 ...

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, ...

A Mouse Model of Retinal Ischemia-Reperfusion Injury Through Elevation of Intraocular Pressure

Retinal ischemia-reperfusion (I/R) is a pathophysiological process contributing to cellular damage in multiple ocular conditions, including glaucoma, diabetic retinopathy, and retinal vascular occlusions. Rodent models of I/R injury are providing significant insights into mechanisms and treatment strategies for human I/R injury, especially with regard to neurodegenerative damage in the retinal neurovascular unit. Presented here is a protocol for inducing retinal I/R injury in mice through elevation of intraocular pressure (IOP). In this protocol, the ocular anterior chamber is cannulated with a needle, through which flows the drip of an elevated saline reservoir. Using this drip to raise IOP above systolic arterial blood pressure, a practitioner temporarily halts inner retinal blood flow (ischemia). When circulation is reinstated (reperfusion) by removal of the cannula, severe cellular damage ensues, resulting ultimately in retinal neurodegeneration. Recent studies demonstrate inflammation, vascular permeability, and capillary degeneration as additional elements of this model. Compared to alternative retinal I/R methodologies, such as retinal arterial ligation, retinal I/R injury by elevated IOP offers advantages in its&#160;anatomical specificity, experimental tractability, and technical accessibility, presenting itself as a valuable tool for examining neuronal pathogenesis and therapy in the retinal neurovascular unit.

This article describes a procedure for inducing retinal ischemia-reperfusion injury by elevated intraocular pressure in mice. Retinal ischemia-reperfusion injury by elevated intraocular pressure serves to model human pathologies characterized by compromised oxygen and nutrient delivery in the retina, enabling researchers to examine potential cellular mechanisms and treatments for human diseases of the retinal neurovascular unit.

Retinal ischemia-reperfusion (I/R) is a pathophysiological process contributing to cellular damage in multiple ocular conditions, including glaucoma, ...

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 ...

A Pre-clinical Rat Model for the Study of Ischemia-reperfusion Injury in Reconstructive Microsurgery

Ischemia-reperfusion injury is the main cause of flap failure in reconstructive microsurgery. The rat is the preferred preclinical animal model in many areas of biomedical research due to its cost-effectiveness and its translation to humans. This protocol describes a method to create a preclinical free skin flap model in rats with ischemia-reperfusion injury. The described 3 cm x 6 cm rat free skin flap model is easily obtained after the placement of several vascular ligatures and the section of the vascular pedicle. Then, 8 h after the ischemic insult and completion of the microsurgical anastomosis, the free skin flap develops the tissue damage. These ischemia-reperfusion injury-related damages can be studied in this model, making it a suitable model for evaluating therapeutic agents to address this pathophysiological process. Furthermore, two main monitoring techniques are described in the protocol for the assessment of this animal model: transit-time ultrasound technology and laser speckle contrast analysis.

Here, we describe a pre-clinical animal model for studying the pathophysiology of ischemia-reperfusion injury in reconstructive microsurgery. This free skin flap model based on the superficial caudal epigastric vessels in the rat may also allow for the evaluation of different therapies and compounds to counteract ischemia-reperfusion injury-related damage.

Ischemia-reperfusion injury is the main cause of flap failure in reconstructive microsurgery. The rat is the preferred preclinical animal model in many ...

Delayed Intramyocardial Delivery of Stem Cells after Ischemia Reperfusion Injury in a Murine Model

There is significant interest in the use of stem cells (SCs) for the recovery of cardiac function in individuals with myocardial injuries. Most commonly, cardiac stem cell therapy is studied by delivering SCs concurrently with the induction of myocardial injury. However, this approach presents two significant limitations: the early hostile pro-inflammatory ischemic environment may affect the survival of transplanted SCs, and it does not represent the subacute infarction scenario where SCs will likely be used. Here we describe a two-part series of surgical procedures for the induction of ischemia-reperfusion injury and delivery of mesenchymal stem cells (MSCs). This method of stem cell administration may allow for the longer viability and retention around damaged tissue by circumventing the initial immune response. A model of ischemia reperfusion injury was induced in mice accompanied by the delivery of mesenchymal stem cells (3.0 x 105), stably expressing the reporter gene firefly luciferase under the constitutively expressed CMV promoter, intramyocardially 7 days later. The animals were imaged via ultrasound and bioluminescent imaging for confirmation of injury and injection of cells, respectively. Importantly, there was no added complication rate when performing this two-procedure approach for SC delivery. This method of stem cell administration, collectively with the utilization of state-of-the-art reporter genes, may allow for the in vivo study of viability and retention of transplanted SCs in a situation of chronic ischemia commonly seen clinically, while also circumventing the initial pro-inflammatory response. In summary, we established a protocol for the delayed delivery of stem cells into the myocardium, which can be used as a potential new approach in promoting regeneration of the damaged tissue.

Stems cells are continuously investigated as potential treatments for individuals with myocardial damage, however, their decreased viability and retention within injured tissue can impact their long-term efficacy. In this manuscript we describe an alternative method for stem cell delivery in a murine model of ischemia reperfusion injury.

There is significant interest in the use of stem cells (SCs) for the recovery of cardiac function in individuals with myocardial injuries. Most commonly, ...

Acute Kidney Injury Model Induced by Cisplatin in Adult Zebrafish

Cisplatin is commonly used as chemotherapy. Although it has positive effects in cancer-treated individuals, cisplatin can easily accumulate in the kidney due to its low molecular weight. Such accumulation causes the death of tubular cells and can induce the development of Acute Kidney Injury (AKI), which is characterized by a quick decrease in kidney function, tissue damage, and immune cells infiltration. If administered in specific doses cisplatin can be a useful tool as an AKI inducer in animal models. The zebrafish has appeared as an interesting model to study renal function, kidney regeneration, and injury, as renal structures conserve functional similarities with mammals. Adult zebrafish injected with cisplatin shows decreased survival, kidney cell death, and increased inflammation markers after 24 h post-injection (hpi). In this model, immune cells infiltration and cell death can be assessed by flow cytometry and TUNEL assay. This protocol describes the procedures to induce AKI in adult zebrafish by intraperitoneal cisplatin injection and subsequently demonstrates how to collect the renal tissue for flow cytometry processing and cell death TUNEL assay. These techniques will be useful to understand the effects of cisplatin as a nephrotoxic agent and will contribute to the expansion of AKI models in adult zebrafish. This model can also be used to study kidney regeneration, in the search for compounds that treat or prevent kidney damage and to study inflammation in AKI. Moreover, the methods used in this protocol will improve the characterization of tissue damage and inflammation, which are therapeutic targets in kidney-associated comorbidities.

This protocol describes the procedures to induce Acute Kidney Injury (AKI) in adult zebrafish using cisplatin as a nephrotoxic agent. We detailed the steps to evaluate the reproducibility of the technique and two techniques to analyze inflammation and cell death in the renal tissue, flow cytometry and TUNEL, respectively.

Cisplatin is commonly used as chemotherapy. Although it has positive effects in cancer-treated individuals, cisplatin can easily accumulate in the kidney ...

Organ Ischemia-Reperfusion Injury by Simulating Hemodynamic Changes in Rat Liver Transplant Model

Orthotopic liver transplantation (OLT) in rats is a tried and proven animal model used for preoperative, intraoperative, and postoperative studies, including ischemia-reperfusion injury (IRI) of extrahepatic organs. This model requires numerous experiments and devices. The duration of anhepatic phase is closely related to the time to develop IRI after transplantation. In this experiment, we used hemodynamic changes to induce extrahepatic organ damage in rats and determined the maximum tolerance time. The time until the most severe organ injury varied for different organs. This method can easily be replicated and can also be used to study IRI of the extrahepatic organs after liver transplantation.

This paper provides a detailed description of how to build an animal model of the anhepatic phase (liver ischemia) in rats to facilitate basic research into ischemia-reperfusion injury after liver transplantation.

Orthotopic liver transplantation (OLT) in rats is a tried and proven animal model used for preoperative, intraoperative, and postoperative studies, ...

A Rat Lung Transplantation Model of Warm Ischemia/Reperfusion Injury: Optimizations to Improve Outcomes

From our experience with rat lung transplantation, we have found several areas for improvement. Information in the existing literature regarding methods for choosing appropriate cuff sizes for the pulmonary vein (PV), pulmonary artery (PA), or bronchus (Br) are varied, thus making the determination of proper cuff size during rat lung transplantation an exercise of trial and error. By standardizing the cuffing technique to use the smallest effective cuff appropriate for the size of the vessel or bronchus, one can make the transplantation procedure safer, faster, and more successful. Since diameters of the PV, PA, and Br are related to the body weight of the rat, we present a strategy to choosing an appropriate size using a weight-based guide. Since lung volume is also related to body weight, we recommend that this relationship should also be considered when choosing the proper volume of air for donor lung inflation during warm ischemia as well as for the proper volume of PBS to be instilled during bronchoalveolar lavage (BAL) fluid collection. We also describe methods for 4th intercostal space dissection, wound closure, and sample collection from both the native and transplanted lobes.

Here, we present optimizations to a rat lung transplantation model that serve to improve outcomes. We provide a size guide for cuffs based on body weight, a measurement strategy to ascertain the 4th intercostal space, and methods of wound closure and BAL (bronchoalveolar lavage) fluid and tissue collection.

From our experience with rat lung transplantation, we have found several areas for improvement. Information in the existing literature regarding methods ...

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 ...