Name: technical refinement of a bilateral renal ischemia-reperfusion mouse model for acute kidney injury research
Uploaded: 2023-11-03T14:20:00.000+00:00
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Description: Watch this Scientific Journal Video about Technical Refinement of a Bilateral Renal Ischemia-Reperfusion Mouse Model for Acute Kidney Injury Research at JoVE.com

This model was developed with the financial support from Ministry of Science and Technology, Taiwan (MOST 109-2320-B-030-006-MY3). This manuscript was edited by Wallace Academic Editing.

All animal experiments were conducted in accordance with the Guide for the Care and Use of Laboratory Animals, published by the US National Institutes of Health (NIH publication no. 85-23, revised 1996). The study protocol was approved by and in accordance with the guidelines of the Institutional Animal Care and Use Committee at Fu-Jen Catholic University. See the Table of Materials for details about all materials and instruments used in this protocol.
1. Preparing the mice
<ol>
	<li>Select 8-week-old C57BL/6 male mice with a weight of 21-23 g.</li>
	<li>House and maintain the mice under a 12 h light and dark cycle at a controlled temperature (21 &#177; 2 &#176;C) with free access to food, standard mouse food pellets, and tap water.</li>
</ol>
2. Anesthesia
<ol>
	<li>Put on a surgical mask and sterile gloves.</li>
	<li>Put the mice under anesthesia with 2% isoflurane mixed with oxygen at 1 L/min in the induction chamber.</li>
	<li>Assess the level of anesthesia by pedal reflex. 
	&#8203;NOTE: Pedal reflex is a retraction of the hind paw in response to a firm toe pinch. The anesthetization is complete when the pedal reflex disappears.</li>
	<li>Move and place each mouse in prone position on a surgery platform with an electric blanket to maintain their body temperature once the anesthetization is complete. Stabilize the body temperature before surgery and monitor with rectal temperature probes.&#160;Apply ophthalmic ointment to both eyes to prevent dryness.</li>
	<li>Tape the paws of the mice to the board.</li>
	<li>Attach a mask to the face of the mice to provide a constant supply of 1% isoflurane and 1 L/min oxygen</li>
	<li>Assess the level of anesthesia by pedal reflex regularly and adjust the anesthetic delivery accordingly during the surgery.</li>
</ol>
3. Bilateral renal IR-AKI surgery
<ol>
	<li>Touch the back and find the lumbar spine of the mice manually. Move along the spine cephalically and look for costovertebral angles that are below both sides of the last rib of the mice.</li>
	<li>Apply hair removal lotion to both sides of the costovertebral angle region for approximately 30 s and then remove the fur with saline.</li>
	<li>Disinfect the shaved skin&#160;with three rounds of&#160;betadine solution and 75% alcohol using cotton balls. 
	NOTE: Maintaining a sterile field for surgery throughout the procedure is key. Apply a surgical drape and use sterile instruments.</li>
	<li>Use fine-tip forceps to gently lift the skin below the left costovertebral angle, and then use scissors&#160;to create a 1 cm oblique dorsolateral incision along the skin tension lines from the lumbar midline on the left flank. Transect the muscle wall of the left flank using scissors to visualize the left kidney.</li>
	<li>Repeat the aforementioned surgical procedures to visualize the right kidney. Remove the small amounts of blood produced during the procedure with sterile cotton swabs.</li>
	<li>Push and separate the left kidney carefully from the surrounding tissue with forceps. Identify the renal pedicle after the left kidney is exposed. 
	NOTE: Be careful not to injure the adrenal gland and the surrounding blood vessels.</li>
	<li>Clamp over the left renal pedicle with a microvascular clip for 25 min. Confirm ischemia by a visible change in kidney color from pink to dark red.</li>
	<li>Cover the clamped kidney with sterile saline wet cotton balls to avoid desiccation during left renal pedicle clamping.</li>
	<li>Repeat the aforementioned surgical procedures to clamp the right renal pedicle with a microvascular clip for 25 min.</li>
	<li>Cover the clamped kidney with sterile saline wet cotton balls to avoid desiccation during right renal pedicle clamping.</li>
	<li>Monitor anesthesia depth and humidity of the sterile saline wet cotton balls periodically.</li>
	<li>Open the left microvascular clip to start reperfusion of the left kidney. Confirm reperfusion by a visible color change of the left kidney from dark red to pink.</li>
	<li>Open the right microvascular clip to start reperfusion of the right kidney.</li>
	<li>After the kidney color change is verified, return the kidney to the abdominal cavity.</li>
	<li>Close the abdominal cavity and skin with 6-0 absorbable suture materials.</li>
	<li>Scrub to disinfect the wound with a betadine solution and 75% alcohol using cotton balls.</li>
	<li>Observe the animal carefully until it begins to move freely and feed. 
	NOTE: Pay close attention to the animals until they have regained sufficient consciousness to maintain sternal recumbency.</li>
	<li>Administer carprofen (5 mg/kg in 0.2 mL, administered subcutaneously) for 2-3 days to prevent postsurgical pain.</li>
</ol>

The authors declare that there is no conflict of interest regarding the publication of this article.

The proposed bilateral IR-AKI protocol is suitable for investigating the mechanism of hypoperfusion and reperfusion injury of both kidneys. The protocol suggests that lightweight mice, general anesthesia with isoflurane, a dorsolateral approach to the surgery, and body temperature maintenance during the operation mitigate the associated technical difficulties, shorten the duration of the surgery, and increase the consistency of the procedure for acute bilateral renal IR-AKI research.
Technical difficulties influence renal damage severity in bilateral renal IR-AKI surgery33. In addition to mouse strain, sex, age, and heating systems36,40,41,42,43,44, proper placement of the vascular clamp is essential for consistent results. Studies have recommended careful dissection of the surrounding adipose tissue to release the kidney and renal pedicles or arteries23,26,32,35,36. Compared with mice aged 8-20 weeks old typically weighing 25-28 g that have been studied in the literature23,32,35,36, this study used relatively young and light mice (8 weeks old and weighing 21-23 g) to reduce the amount of perirenal adipose tissue, which could expose the kidney and renal pedicles easily without requiring peripheral tissue dissection and proper placement of the vascular clamps. This would reduce procedure-related trauma and the technical complexity, shorten anesthesia and surgery duration, quicken the learning curve for those unfamiliar with the study procedure, and increase the reproducibility of the study.
General anesthesia influences the results of an IR-AKI study. Prolonged anesthesia increases animal loss during surgery33. In the literature, phenobarbital sodium, a long-acting barbiturate that depresses the central nervous system, has been administered subcutaneously for IR-AKI surgery26,33,35. Phenobarbital sets in after 5 min and helps achieve surgical anesthesia in at least 15 min45. Therefore, phenobarbital should be delivered only by skilled surgeons to avoid prolonging anesthesia (&#62;60 mg/kg) and animal loss during surgery33. By contrast, this study&#39;s use of isoflurane, which is a nonflammable inhaled anesthetic, induced a rapid onset that achieved surgical anesthesia in 7-10 min and ceased the effect in 15 min after stopping the inhalation46. The delivery of isoflurane, in conjunction with oxygen, is easy for the operator to start, maintain, and stop instantly during surgery and is suggested for renal IR-AKI surgery.
Finally, the method to approaching the renal pedicles may influence the quality of IR-AKI surgery. Some IR-AKI studies have investigated the renal pedicle using midline laparotomy where the abdominal cavity was opened, and the peritoneum and intestines were pushed aside to access the kidney. However, doing so may increase fluid and heat loss, surgery-related trauma, and surgical duration32,35. Therefore, this protocol suggests a dorsolateral approach for IR-AKI research to expose the kidney from the flank and the retroperitoneum to maintain body temperature and to minimize surgery-related injury, subsequently improving the surgical condition and study consistency.
This model has a potential application in studies aiming to identify and characterize markers of bilateral renal damage caused by cardiac arrest following ROSC. However, cytokines released due to surgical damage during the procedure may influence the study results, making them unrelatable to the clinical scenario and limiting the translation of the study results from benchside to bedside.

Cardiac arrest occurs more than 80,000 times annually in the United States1,2. The mortality rate of cardiac arrest is extremely high3,4,5,6. AKI is a major risk factor associated with high mortality and poor neurological outcomes in patients with cardiac arrest after ROSC7,8,9,10,11,12,13. Recovery from AKI is a good predictor of favorable neurological outcomes and discharge from the hospital14,15,16. However, effective therapies for IR-AKI are still lacking15,16,17,18,19. Additional therapeutic strategies are required to further improve the clinical outcomes of the disease.
IR-AKI with bilateral renal ischemia approach is one of the animal models used for AKI research20,21,22,23,24,25,26. Renal IR-AKI animal models are less complicated than a whole-body IR injury model for the study of AKI in patients with sudden cardiac arrest following ROSC6,27,28,29,30. This implies that consistent results from a renal IR-AKI animal model are easier to achieve because of the presence of fewer confounding factors in experiments. Moreover, renal IR-AKI protocols commonly involve a unilateral or bilateral renal pedicle occlusion. Conditions in experiments on bilateral renal IR-AKI are comparable to clinical conditions for AKI following ROSC in patients with sudden cardiac arrest after successful cardiopulmonary resuscitation. Although the pathological characteristics of the kidneys in both models reflect the pathological characteristics of human renal IR injury31,32,33, a bilateral renal ischemia approach is more relevant to AKI under human pathological conditions, such as cardiac failure, vasoconstriction, and septic shock35. Bilateral renal IR-AKI animal models are suitable for studies focusing on renal IR injuries in cardiac arrest following ROSC.
Bilateral renal IR-AKI models are associated with technical difficulties, experimental complexity, and long surgery duration23,26,32,33,35,36. To overcome these technical difficulties, the present study established a reliable bilateral IR-AKI research protocol in mice by making some technical modifications. The proposed protocol resulted in fewer surgical complications, less tissue damage, and a lower likelihood of mortality during surgery. Therefore, it can be used to investigate the pathophysiological processes of AKI after ROSC to develop new therapeutic strategies against renal hypoperfusion and reperfusion damage37,38,39.

<table><tbody><tr><td>Absorbable Suture, 6-0</td><td>Ethicon</td><td>J510G-BX</td><td></td></tr><tr><td>Betadine solution</td><td>Shineteh Istrument</td><td></td><td></td></tr><tr><td>Carprofen</td><td>Sigma</td><td>PHR1452</td><td></td></tr><tr><td>Cotton balls</td><td>Shineteh Istrument</td><td></td><td></td></tr><tr><td>Graefe Forceps</td><td>Fine Science Tools</td><td>11051-10</td><td></td></tr><tr><td>Heating pad</td><td>Shineteh Istrument</td><td></td><td></td></tr><tr><td>Isoflurane</td><td>Piramal Critical Care Inc.</td><td>26675-46-7</td><td></td></tr><tr><td>Moria Vessel Clamp</td><td>Fine Science Tools</td><td>18320-11</td><td></td></tr><tr><td>Olsen-Hegar needle holder</td><td>Fine Science Tools</td><td>12002 - 12</td><td></td></tr><tr><td>Saline</td><td>Shineteh Istrument</td><td></td><td></td></tr><tr><td>Scalpel blades</td><td>Shinva</td><td>s2646</td><td></td></tr><tr><td>Small Animal Anesthesia Machine</td><td>Sheng-Cing Instruments Co.</td><td>STEP AS-01</td><td></td></tr><tr><td>Tissue scissors</td><td>Fine Science Tools</td><td>14072 - 10</td><td></td></tr></tbody></table>

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.

The quality of the bilateral renal IR-AKI surgery should be assessed before further microscopic or molecular analysis. During surgery, renal ischemia should be confirmed by seeing whether the kidney has changed color from pink to dark red soon after the renal pedicle is clamped with a microvascular clip (Figure 1). After surgery, kidney damage caused by IR-AKI surgery can be further validated with a few microliters of serum through submandibular blood collection for biochemical analysis where the results indicate an increase in the level of blood urea nitrogen and creatinine from baseline (Figure 2).
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/63957/63957fig01.jpg" /> 
Figure 1: Renal ischemia after renal pedicle clamping. A kidney color change from pink to dark red revealing that the kidney perfusion has become inadequate. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63957/63957fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/63957/63957fig02.jpg" /> 
Figure 2: Renal insufficiency after bilateral IR-AKI surgery. Serum levels of blood urea nitrogen and creatinine increased 2 days after renal reperfusion. Abbreviations: IR-AKI = ischemia-reperfusion-induced acute kidney injury; BUN = blood urea nitrogen; I/R = ischemia-reperfusion (n = 4, *p &#60; 0.05 versus control). <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63957/63957fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Technical Refinement of a Bilateral Renal Ischemia-Reperfusion Mouse Model for Acute Kidney Injury Research at JoVE.com

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

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 ...

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2.1K Views.  Fu Jen Catholic University. This study established a protocol focusing on the technical refinement of a mouse model of bilateral renal ischemia-reperfusion for acute kidney injury research.

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

Use of a Hanging-weight System for Isolated Renal Artery Occlusion

In hospitalized patients, over 50% of cases of acute kidney injury (AKI) are caused by renal ischemia 1-3. A recent study of hospitalized patients revealed that only a mild increase in serum creatinine levels (0.3 to 0.4 mg/dl) is associated with a 70% greater risk of death than in persons without any increase 1. Along these lines, surgical procedures requiring cross-clamping of the aorta and renal vessels are associated with a renal failure rates of up to 30% 4. Similarly, AKI after cardiac surgery occurs in over 10% of patients under normal circumstances and is associated with dramatic increases in mortality. AKI are also common complications after liver transplantation. At least 8-17% of patients end up requiring renal replacement therapy 5. Moreover, delayed graft function due to tubule cell injury during kidney transplantation is frequently related to ischemia-associated AKI 6. Moreover, AKI occurs in approximately 20% of patients suffering from sepsis 6.The occurrence of AKI is associated with dramatic increases of morbidity and mortality 1. Therapeutic approaches are very limited and the majority of interventional trials in AKI have failed in humans. Therefore, additional therapeutic modalities to prevent renal injury from ischemia are urgently needed 3, 7-9. 
To elucidate mechanisms of renal injury due to ischemia and possible therapeutic strategies murine models are intensively required 7-13. Mouse models provide the possibility of utilizing different genetic models including gene-targeted mice and tissue specific gene-targeted mice (cre-flox system). However, murine renal ischemia is technically challenging and experimental details significantly influence results. We performed a systematic evaluation of a novel model for isolated renal artery occlusion in mice, which specifically avoids the use of clamping or suturing the renal pedicle 14. This model requires a nephrectomy of the right kidney since ischemia can be only performed in one kidney due to the experimental setting. In fact, by using a hanging-weight system, the renal artery is only instrumented once throughout the surgical procedure. In addition, no venous or urethral obstruction occurs with this technique. We could demonstrate time-dose-dependent and highly reproducible renal injury with ischemia by measuring serum creatinine. Moreover, when comparing this new model with conventional clamping of the whole pedicle, renal protection by ischemic preconditioning is more profound and more reliable. Therefore his new technique might be useful for other researchers who are working in the field of acute kidney injury.

A precise murine model for acute kidney injury (AKI) due to ischemia is an important tool to investigate acute kidney injury and possibly find therapeutic tools to treat renal injury. The hanging weight system offers a tool for immediate and reliable renal artery occlusion and reperfusion without causing renal congestion.

In hospitalized patients, over 50% of cases of acute kidney injury (AKI) are caused by renal ischemia 1-3. A recent study of hospitalized patients ...

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 ...

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.

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 ...

A Murine Model of Myocardial Ischemia-reperfusion Injury through Ligation of the Left Anterior Descending Artery

Acute or chronic myocardial infarction (MI) are cardiovascular events resulting in high morbidity and mortality. Establishing the pathological mechanisms at work during MI and developing effective therapeutic approaches requires methodology to reproducibly simulate the clinical incidence and reflect the pathophysiological changes associated with MI. Here, we describe a surgical method to induce MI in mouse models that can be used for short-term ischemia-reperfusion (I/R) injury as well as permanent ligation. The major advantage of this method is to facilitate location of the left anterior descending artery (LAD) to allow for accurate ligation of this artery to induce ischemia in the left ventricle of the mouse heart. Accurate positioning of the ligature on the LAD increases reproducibility of infarct size and thus produces more reliable results. Greater precision in placement of the ligature will improve the standard surgical approaches to simulate MI in mice, thus reducing the number of experimental animals necessary for statistically relevant studies and improving our understanding of the mechanisms producing cardiac dysfunction following MI. This mouse model of MI is also useful for the preclinical testing of treatments targeting myocardial damage following MI.

We introduce a surgical method to induce experimental ischemia/reperfusion (I/R) injury to simulate myocardial infarction (MI) in mouse models that allows for more clarity in positioning of the ligation on the left anterior descending artery (LAD) to increase the reproducibility of MI experiments in mice.

Acute or chronic myocardial infarction (MI) are cardiovascular events resulting in high morbidity and mortality. Establishing the pathological mechanisms ...

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 ...

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 Large Animal Model for Acute Kidney Injury by Temporary Bilateral Renal Artery Occlusion

Acute kidney injury (AKI) is associated with higher risk for morbidity and mortality post-operatively. Ischemia-reperfusion injury (IRI) is the most common cause of AKI. To mimic this clinical scenario, this study presents a highly reproducible large animal model of renal IRI in swine using temporary percutaneous bilateral balloon-catheter occlusion of the renal arteries. The renal arteries are occluded for 60 min by introducing the balloon-catheters through the femoral and carotid artery and advancing them into the proximal portion of the arteries. Iodinated contrast is injected in the aorta to assess any opacification of the kidney vessels and confirm the success of the artery occlusion. This is furtherly confirmed by the flattening of the pulse waveform at the tip of the balloon catheters. The balloons are deflated and removed after 60 min of bilateral renal artery occlusion, and the animals are allowed to recover for 24 h. At the end of the study, plasma creatinine and blood urea nitrogen significantly increase, while eGFR and urine output significantly decrease. The need for iodinated contrast is minimal and does not affect renal function. Bilateral renal artery occlusion better mimics the clinical scenario of perioperative renal hypoperfusion, and the percutaneous approach minimizes the impact of the inflammatory response and the risk of infection seen with an open approach, such as a laparotomy. The ability to create and reproduce this clinically relevant swine model eases the clinical translation to humans.

This study presents a highly reproducible large animal model of renal ischemia-reperfusion injury in swine using temporary percutaneous bilateral balloon-catheter occlusion of the renal arteries for 60 min and reperfusion for 24 h.

Acute kidney injury (AKI) is associated with higher risk for morbidity and mortality post-operatively. Ischemia-reperfusion injury (IRI) is the most ...

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

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 ...