The authors gratefully acknowledge Bertha Delgado, Department of Pathology, Soroka Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, for her help in the laboratory as well as in the histology analysis.

The experiments were conducted according to the recommendations of the Declarations of Helsinki and Tokyo and to the Guidelines for the Use of Experimental Animals of the European Community. The experiments were approved by the Animal Care Committee of Ben-Gurion University of the Negev.
NOTE: The CCl4 model has been generated and used in a previous study17. The protocol timeline is demonstrated in Table 1.
1. Preparing rats for the experimental procedure
NOTE: Select adult male Sprague Dawley rats weighing 300&#8722;350 g.
<ol>
	<li>Obtain approval for experiments from Institutional Animal Care and Use Committee (IACUC).</li>
	<li>Maintain rats at room temperature (22 &#176;C &#177; 1 &#176;C), with 12 h light and 12 h dark cycles. Provide rat chow and water ad libitum.</li>
	<li>Perform all experiments between 6:00 a.m. and 12:00 p.m.</li>
	<li>Shave the rat and disinfect the skin with alcohol.</li>
</ol>
2. Determination of serum GOT, GPT, and TB baseline levels
<ol>
	<li>Anesthesia
	<ol>
		<li>Prepare a continuous isoflurane administration system to induce anesthesia. Make sure the vaporizer system is filled with isoflurane.</li>
		<li>Anesthetize the rat with 2% isoflurane. Confirm that the rat is fully anesthetized by observing the movement and pedal reflex in response to external stimuli. 
		NOTE: Use 1&#8722;5% isoflurane for anesthesia induction and maintenance.</li>
	</ol>
	</li>
	<li>Cannulate the tail vein with a 22 G catheter.</li>
	<li>Collect a 0.5 mL blood sample at baseline. Ensure that the blood volume retrieved does not exceed IACUC guidelines.</li>
	<li>Perform blood biochemical analysis including the measurements of serum GOT, GPT and TB, as previously described18. 
	NOTE: Examinations of liver enzymes and TB level were carried out in the biochemical laboratory of Soroka Medical Center. Blood samples were analyzed using a fluorescence method on a chemistry analyzer (Table of Materials).</li>
</ol>
3. Induction of acute liver injury in rats
CAUTION: Exposure to high concentrations of CCl4, including absorption through vapor or skin, can have negative effects on the central nervous system and cause degeneration of the liver and kidneys. Prolonged exposure can cause coma or death.
<ol>
	<li>Prepare a 50% solution of CCl4 (Table of Materials) by mixing CCl4 with olive oil as a vehicle in a 1:1 ratio. 
	NOTE: The solution should be prepared according to IACUC guidelines for non-pharmaceutical grade compounds.</li>
	<li>Induce hepatotoxicity in vivo by CCl4 administration via an orogastric tube.
	<ol>
		<li>Insert a 16 G orogastric tube (3 inches deep) through the oral cavity of the rat.</li>
		<li>Expose the rat to different doses of CCl4 by injecting a syringe with one of the following diluted solutions into the rat&#8217;s stomach: 1 mL/kg (mild ALI), 2.5 mL/kg (moderate ALI), or 5 mL/kg (severe ALI) of the 50% solution. For the sham-operated control group, expose the rat to 5 mL/kg olive oil only.</li>
	</ol>
	</li>
</ol>
4. Determination of serum GOT, GPT, and TB levels after 24 h
<ol>
	<li>Anesthesia
	<ol>
		<li>Prepare a continuous isoflurane administration system to induce anesthesia. Make sure the vaporizer system is filled with isoflurane.</li>
		<li>Anesthetize the rats with 2% isoflurane. Confirm that the rat is fully anesthetized by observing the movement and pedal reflex in response to external stimuli.</li>
	</ol>
	</li>
	<li>Collect blood samples at 24 h from CCl4 exposure.</li>
	<li>Perform blood biochemical analysis including measurements of serum GOT, GPT and TB.</li>
</ol>
5. Liver collection for histological examination
<ol>
	<li>Euthanize the rat by replacing the inspired gas mixture with 20% O2/80% CO2. Ensure that CO2 is delivered at a predetermined rate in accordance with IACUC guidelines.</li>
	<li>Ensure death by checking for lack of heartbeat and confirm by a secondary method in accordance with IACUC guidelines.</li>
	<li>Place the rat on a dissecting board with its dorsal surface facing down and abdomen facing up. Shave the abdomen of the rat.</li>
	<li>With a scalpel, incise the full length of the ventrum skin from the anus to the chin. Separate the skin. Incise the abdominal wall with a scalpel from the anus to the xyphoid cartilage, exposing the abdominal viscera.</li>
	<li>Using scissors and forceps, isolate the liver by dissecting it from its ligaments and attachments. Starting at the liver hilum, carefully perform a hepatectomy by releasing all the liver lobes from attachments. Dissect and cut away all ligaments and blood vessels.</li>
	<li>Transfer the liver into a Petri dish. Fix the liver in a 4% buffered formaldehyde solution (Table of Materials) for at least 24 h.</li>
</ol>
6. Histological examination
<ol>
	<li>Sample preparation
	<ol>
		<li>After fixation, cut the sample into 5 &#956;m thick slice series by microtome sectioning.</li>
		<li>Gently place the slices on glass slides with a soft brush, 1 slice per slide.</li>
		<li>Perform H&#38;E staining as previously described19.</li>
	</ol>
	</li>
	<li>Examine the slices under a microscope at 200x magnification using a 20 mm objective lens (Table of Materials). 
	NOTE: The liver sections should be graded by a specialized pathologist blinded to the treatment protocol. A score of 0 indicates no liver abnormalities, 1&#8211;2 indicates mild liver injury, 3&#8211;4 indicates moderate liver injury, and 5&#8211;6 indicates severe liver injury20,21,22.</li>
</ol>

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The authors have nothing to disclose.

In this protocol, CCl4 is used as a liver toxin to induce ALI in rats. ALI is characterized by loss of hepatic parenchyma and subsequent dysregulation of the liver&#8217;s metabolic and synthetic functions. Drugs, viruses, toxins, autoimmune diseases, metabolic diseases, and vascular disorders all induce hepatocyte death, and the subsequent inflammatory response contributes to the pathogenesis of ALI.
The initial insult to the liver leads to cytokine production, chemokine release, a...

The frequency of toxic insults to the liver, especially due to alcohol and drug abuse, is increasing. Acute liver injury (ALI) is associated with high mortality rates and has caused clinical concerns1,2. Toxic injury leads to death signaling pathways in the liver, resulting in hepatocyte apoptosis, necrosis, or pyroptosis. ALI plays a crucial role in the development of hepatic failure, which is characterized by severe liver dysfunction including complications such as hepatic encephalopathy and impaired protein synthesis3,4. Although recent research has increased our knowledge about the physiological and pathological changes accompanying hepatic failure, it has not completely explained the pathomolecular features that affect the mechanisms of cell death. Furthermore, no medications are currently available to reverse the progressive deterioration in ALI patients. Currently, the only significantly effective treatment is liver transplantation5,6.
In order to investigate the mechanism and pathophysiology of ALI and to test different hepatoprotective strategies, different animal models are used to induce ALI. A preferable animal model of ALI should mimic the pathological process of the disease via a reliable, validated, inexpensive and easy to apply method. Examples of experimental models include hepatotoxic agents, surgical procedures such as total or partial hepatectomy, complete or transient devascularization, and infective procedures7,8,9. Known hepatotoxic substances include galactosamine, acetaminophen, thioacetamide, azoxymethane and CCl4. Of these, CCl4 is widely used although it has not yet been well characterized10,11,12,13.
CCl4 is an organic colorless liquid compound with a sweet smell and almost no flammability at lower temperatures. Exposure to high concentrations of CCl4 can cause damage to the central nervous system, including deterioration of the liver and kidneys. CCl4 induces ALI through its biotransformation in the liver, which forms reactive oxygen species. This occurs via the P450 cytochrome enzyme 2E1, forming an active metabolite and resulting in cell damage by macromolecule binding, enhancement of lipid peroxidation and disturbance of intracellular calcium homeostasis14. In addition, the CCl4 model can be used to stimulate the astrocytes at the level of RNA synthesis15. This hepatotoxin has been administered by the intraperitoneal, intraportal, oral, and intragastric routes16.
In this protocol, we describe in detail CCl4-induced ALI in rats via an orogastric tube. This method induces robust and reproducible ALI that can be used to investigate the pathogenesis of ALI. Determination of liver disease severity is monitored by measurement of serum glutamate-pyruvate transaminase (GPT), glutamic oxaloacetic transaminase&#160;(GOT) enzymes and total bilirubin (TB) as well as definitive histological diagnosis by hematoxylin and eosin (H&#38;E) stained liver tissues. Exposure to CCl4 through an intragastric access allows for a practical, inexpensive, minimally invasive method with minimal hazard risk.

<table border="0" cellpadding="0" cellspacing="0" style="width:924px;" width="923">
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	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:212px;">22 G catheter BD Neoflon TM</td>
			<td style="width:153px;">Becton Dickinson Infusion Therapy AB</td>
			<td style="width:116px;"></td>
			<td style="width:443px;"></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:212px;">4% buffered formaldehyde solution</td>
			<td style="width:153px;">Sigma - Aldrich lab materials technologies</td>
			<td style="width:116px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:212px;">BD Microtainer SST TM Tubes</td>
			<td style="width:153px;">Becton Dickinson and Company</td>
			<td style="width:116px;"></td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:212px;">Carbone tetrachloride</td>
			<td style="width:153px;">Sigma - Aldrich lab materials technologies</td>
			<td style="width:116px;">CAS 56-23-5</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:212px;">Isofluran, USP 100%</td>
			<td style="width:153px;">Piramamal Critical Care, Inc</td>
			<td style="width:116px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:212px;">Olympus AU2700 Chemistry-Immuno Analyzer</td>
			<td style="width:153px;">Olympus (MN, USA)</td>
			<td style="width:116px;"></td>
			<td>Analysis of blood samples was done by the fluorescence method</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:212px;">Olympus BX 40 microscope</td>
			<td style="width:153px;">Olympus</td>
			<td style="width:116px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:212px;">RAT Feeding Needles</td>
			<td style="width:153px;">ORCHID SCIENTIFICS</td>
			<td style="width:116px;"></td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:212px;">SYRINGE SET 1 and 2 ml MEDI -PLUS</td>
			<td style="width:153px;">Shandong Zibo Shanchuan Medical Instruments Co., Ltd</td>
			<td style="width:116px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

inducing acute liver injury in rats via carbon tetrachloride (ccl4) exposure through an orogastric tube

Acute liver injury (ALI) plays a crucial role in the development of hepatic failure, which is characterized by severe liver dysfunction including complications such as hepatic encephalopathy and impaired protein synthesis. Appropriate animal models are vital to test the mechanism and pathophysiology of ALI and investigate different hepatoprotective strategies. Due to its ability to perform chemical transformations, carbon tetrachloride (CCl4) is widely used in the liver to induce ALI through the formation of reactive oxygen species. CCl4 exposure can be performed intraperitoneally, by inhalation, or through a nasogastric or orogastric tube. Here, we describe a rodent model, in which ALI is induced by CCl4 exposure through an orogastric tube. This method is inexpensive, easily performed, and has minimal hazard risk. The model is highly reproducible and can be widely used to determine the efficacy of potential hepatoprotective strategies and assess markers of liver injury.

The TB, GOT, and GPT levels significantly increased 24 h after inducing ALI (more at higher CCl4 doses) compared to sham-operated controls (p &#60; 0.001) (Figure 1). The levels of TB, GOT, and GPT at baseline were normal and were not significantly different than sham-operated controls. At 24 h, all three interventional groups, 1 mL/kg CCl4 (1, 1&#8722;2), 2.5 mL/kg CCl4 (3, 3&#8722;4), and 5 mL/kg CCl4 (4, 4&#8722;5.75), had a significantly higher...

Watch this Scientific Journal Video about Inducing Acute Liver Injury in Rats via Carbon Tetrachloride CCl4 Exposure Through an Orogastric Tube at JoVE.com

Inducing Acute Liver Injury in Rats via Carbon Tetrachloride CCl4 Exposure Through an Orogastric Tube

This protocol describes a common and feasible method of inducing acute liver injury (ALI) via CCl4 exposure through an orogastric tube. CCl4 exposure induces ALI through the formation of reactive oxygen species during its biotransformation in the liver. This method is used to analyze the pathophysiology of ALI and examine different hepatoprotective strategies.

Inducing Acute Liver Injury in Rats via Carbon Tetrachloride (CCl4) Exposure Through an Orogastric Tube

Acute liver injury (ALI) plays a crucial role in the development of hepatic failure, which is characterized by severe liver dysfunction including ...

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11.1K Views.  Ben-Gurion University of the Negev. This protocol describes a common and feasible method of inducing acute liver injury (ALI) via CCl4 exposure through an orogastric tube. CCl4 exposure induces ALI through the formation of reactive oxygen species during its biotransformation in the liver. This method is used to analyze the pathophysiology of ALI and examine different hepatoprotective strategies.

Video: Inducing Acute Liver Injury in Rats via Carbon Tetrachloride CCl4 Exposure Through an Orogastric Tube

Acute Myocardial Infarction in Rats

With heart failure leading the cause of death in the USA (Hunt), biomedical research is fundamental to advance medical treatments for cardiovascular diseases. Animal models that mimic human cardiac disease, such as myocardial infarction (MI) and ischemia-reperfusion (IR) that induces heart failure as well as pressure-overload (transverse aortic constriction) that induces cardiac hypertrophy and heart failure (Goldman and Tarnavski), are useful models to study cardiovascular disease. In particular, myocardial ischemia (MI) is a leading cause for cardiovascular morbidity and mortality despite controlling certain risk factors such as arteriosclerosis and treatments via surgical intervention (Thygesen). Furthermore, an acute loss of the myocardium following myocardial ischemia (MI) results in increased loading conditions that induces ventricular remodeling of the infarcted border zone and the remote non-infarcted myocardium. Myocyte apoptosis, necrosis and the resultant increased hemodynamic load activate multiple biochemical intracellular signaling that initiates LV dilatation, hypertrophy, ventricular shape distortion, and collagen scar formation. This pathological remodeling and failure to normalize the increased wall stresses results in progressive dilatation, recruitment of the border zone myocardium into the scar, and eventually deterioration in myocardial contractile function (i.e. heart failure). The progression of LV dysfunction and heart failure in rats is similar to that observed in patients who sustain a large myocardial infarction, survive and subsequently develops heart failure (Goldman). The acute myocardial infarction (AMI) model in rats has been used to mimic human cardiovascular disease; specifically used to study cardiac signaling mechanisms associated with heart failure as well as to assess the contribution of therapeutic strategies for the treatment of heart failure. The method described in this report is the rat model of acute myocardial infarction (AMI). This model is also referred to as an acute ischemic cardiomyopathy or ischemia followed by reperfusion (IR); which is induced by an acute 30-minute period of ischemia by ligation of the left anterior descending artery (LAD) followed by reperfusion of the tissue by releasing the LAD ligation (Vasilyev and McConnell). This protocol will focus on assessment of the infarct size and the area-at-risk (AAR) by Evan's blue dye and triphenyl tetrazolium chloride (TTC) following 4-hours of reperfusion; additional comments toward the evaluation of cardiac function and remodeling by modifying the duration of reperfusion, is also presented. Overall, this AMI rat animal model is useful for studying the consequence of a myocardial infarction on cardiac pathophysiological and physiological function.

The rat model of acute myocardial infarction (AMI) is useful to study the consequence of a MI on cardiac pathophysiological and physiological function.

With heart failure leading the cause of death in the USA (Hunt), biomedical research is fundamental to advance medical treatments for cardiovascular ...

Pressure Controlled Ventilation to Induce Acute Lung Injury in Mice

Murine models are extensively used to investigate acute injuries of different organs systems (1-34). Acute lung injury (ALI), which occurs with prolonged mechanical ventilation, contributes to morbidity and mortality of critical illness, and studies on novel genetic or pharmacological targets are areas of intense investigation (1-3, 5, 8, 26, 30, 33-36). ALI is defined by the acute onset of the disease, which leads to non-cardiac pulmonary edema and subsequent impairment of pulmonary gas exchange (36). We have developed a murine model of ALI by using a pressure-controlled ventilation to induce ventilator-induced lung injury (2). For this purpose, C57BL/6 mice are anesthetized and a tracheotomy is performed followed by induction of ALI via mechanical ventilation. Mice are ventilated in a pressure-controlled setting with an inspiratory peak pressure of 45 mbar over 1 - 3 hours. As outcome parameters, pulmonary edema (wet-to-dry ratio), bronchoalveolar fluid albumin content, bronchoalveolar fluid and pulmonary tissue myeloperoxidase content and pulmonary gas exchange are assessed (2). Using this technique we could show that it sufficiently induces acute lung inflammation and can distinguish between different treatment groups or genotypes (1-3, 5). Therefore this technique may be helpful for researchers who pursue molecular mechanisms involved in ALI using a genetic approach in mice with gene-targeted deletion.

A murine model for ventilator induced lung injury is an important tool to study an acute lung injury in vivo. Here, we report an easy applicable in situ model for acute lung injury using high-pressure mechanical ventilation to induce acute failure of the lung.

Murine models are extensively used to investigate acute injuries of different organs systems (1-34). Acute lung injury (ALI), which occurs with prolonged ...

X-ray Dose Reduction through Adaptive Exposure in Fluoroscopic Imaging

X-ray fluoroscopy is widely used for image guidance during cardiac intervention. However, radiation dose in these procedures can be high, and this is a significant concern, particularly in pediatric applications. Pediatrics procedures are in general much more complex than those performed on adults and thus are on average four to eight times longer1. Furthermore, children can undergo up to 10 fluoroscopic procedures by the age of 10, and have been shown to have a three-fold higher risk of developing fatal cancer throughout their life than the general population2,3.
We have shown that radiation dose can be significantly reduced in adult cardiac procedures by using our scanning beam digital x-ray (SBDX) system4-- a fluoroscopic imaging system that employs an inverse imaging geometry5,6 (Figure 1, Movie 1 and Figure 2). Instead of a single focal spot and an extended detector as used in conventional systems, our approach utilizes an extended X-ray source with multiple focal spots focused on a small detector. Our X-ray source consists of a scanning electron beam sequentially illuminating up to 9,000 focal spot positions. Each focal spot projects a small portion of the imaging volume onto the detector. In contrast to a conventional system where the final image is directly projected onto the detector, the SBDX uses a dedicated algorithm to reconstruct the final image from the 9,000 detector images.
For pediatric applications, dose savings with the SBDX system are expected to be smaller than in adult procedures. However, the SBDX system allows for additional dose savings by implementing an electronic adaptive exposure technique. Key to this method is the multi-beam scanning technique of the SBDX system: rather than exposing every part of the image with the same radiation dose, we can dynamically vary the exposure depending on the opacity of the region exposed. Therefore, we can significantly reduce exposure in radiolucent areas and maintain exposure in more opaque regions. In our current implementation, the adaptive exposure requires user interaction (Figure 3). However, in the future, the adaptive exposure will be real time and fully automatic.
We have performed experiments with an anthropomorphic phantom and compared measured radiation dose with and without adaptive exposure using a dose area product (DAP) meter. In the experiment presented here, we find a dose reduction of 30%.

We are developing a dynamic adaptive exposure technique using our scanning beam digital X-ray system. Rather than exposing an object uniformly, the exposure is adapted depending on the opacity of the object. Here we show an experiment on an anthropomorphic phantom that resulted in a dose saving of 30%.

X-ray fluoroscopy is widely used for image guidance during cardiac intervention. However, radiation dose in these procedures can be high, and this is a ...

Acute and Chronic Tactile Sensory Testing after Spinal Cord Injury in Rats

Spinal cord injury (SCI) impairs sensory systems causing allodynia1-8. To identify cellular and molecular causes of allodynia, sensitive and valid sensory testing in rat SCI models is needed. However, until recently, no single testing approach had been validated for SCI so that standardized methods have not been implemented across labs. Additionally, available testing methods could not be implemented acutely or when severe motor impairments existed, preventing studies of the development of SCI-induced allodynia3. Here we present two validated sensory testing methods using von Frey Hair (VFH) monofilaments which quantify changes in tactile sensory thresholds after SCI4-5. One test is the well-established Up-Down test which demonstrates high sensitivity and specificity across different SCI severities when tested chronically5. The other test is a newly-developed dorsal VFH test that can be applied acutely after SCI when allodynia develops, prior to motor recovery4-5. Each VFH monofilament applies a calibrated force when touched to the skin of the hind paw until it bends. In the up-down method, alternating VFHs of higher or lower forces are used on the plantar L5 dermatome to delineate flexor withdrawal thresholds. Successively higher forces are applied until withdrawal occurs then lower force VFHs are used until withdrawal ceases. The tactile threshold reflects the force required to elicit withdrawal in 50% of the stimuli. For the new test, each VFH is applied to the dorsal L5 dermatome of the paw while the rat is supported by the examiner. The VFH stimulation occurs in ascending order of force until at least 2 of 3 applications at a given force produces paw withdrawal. Tactile sensory threshold is the lowest force to elicit withdrawal 66% of the time. Acclimation, testing and scoring procedures are described. Aberrant trials that require a retest and typical trials are defined. Animal use was approved by Ohio State University Animal Care and Use Committee.

We describe two tactile sensory testing methods for acute or chronic periods of spinal cord injury in rats. These validated procedures can detect the development and maintenance of allodynia-like sensations.

Spinal cord injury (SCI) impairs sensory systems causing allodynia1-8. To identify cellular and molecular causes of allodynia, sensitive and valid sensory ...

Orthotopic Liver Transplantation in Rats

Clinical progress in the field of liver transplantation has been largely supported by animal models1,2. Since the publication of the first orthotopic rat liver transplantation in 1979 by Kamada et al.3, this model has remained the gold standard despite various proposed alternative techniques4. Nevertheless, its broader use is limited by its steep learning curve5.
In this video paper, we show a simple and easy-to-establish revision of Kamada's two-cuff technique. The suprahepatic vena cava anastomosis is performed manually with a running suture, and the vena porta and infrahepatic vena cava anastomoses are performed utilizing a quick-linker cuff system6. Manufacturing the quick-linker kit is shown in a separate video paper.

We present an easy-to-establish revision of the classical two-cuff technique for orthotopic liver transplantation in rat.

Clinical progress in the field of liver transplantation has been largely supported by animal models1,2. Since the publication of the first orthotopic rat ...

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 ...

Open Tracheostomy Gastric Acid Aspiration Murine Model of Acute Lung Injury Results in Maximal Acute Nonlethal Lung Injury

Acid pneumonitis is a major cause of sterile acute lung injury (ALI) in humans. Acid pneumonitis spans the clinical spectrum from asymptomatic to acute respiratory distress syndrome (ARDS), characterized by neutrophilic alveolitis, and injury to both alveolar epithelium and vascular endothelium. Clinically, ARDS is defined by acute onset of hypoxemia, bilateral patchy pulmonary infiltrates and non-cardiogenic pulmonary edema. Human studies have provided us with valuable information about the physiological and inflammatory changes in the lung caused by ARDS, which has led to various hypotheses about the underling mechanisms. Unfortunately, difficulties determining the etiology of ARDS, as well as a wide range of pathophysiology have resulted in a lack of critical information that could be useful in developing therapeutic strategies.
Translational animal models are valuable when their pathogenesis and pathophysiology accurately reproduce a concept proven in both in vitro and clinical settings. Although large animal models (e.g., sheep) share characteristics of the anatomy of human trachea-bronchial tree, murine models provide a host of other advantages including: low cost; short reproductive cycle lending itself to greater data acquisition; a well understood immunologic system; and a well characterized genome leading to the availability of a variety of gene deletion and transgenic strains. A robust model of low pH induced ARDS requires a murine ALI that targets mainly the alveolar epithelium, secondarily the vascular endothelium, as well as the small airways leading to the alveoli. Furthermore, a reproducible injury with wide differences between different injurious and non-injurious insults is important.
The murine gastric acid aspiration model presented here using hydrochloric acid employs an open tracheostomy and recreates a pathogenic scenario that reproduces the low pH pneumonitis injury in humans. Additionally, this model can be used to examine interaction of a low pH insult with other pulmonary injurious entities (e.g., food particles, pathogenic bacteria).

This protocol induces acute lung injury in a mouse that has close fidelity to the pathogenesis of acid pneumonitis observed in humans. We generate a maximal acute nonlethal low pH lung injury and account for differences in rodent-human anatomic respiratory structure using an open tracheostomy coupled with circumferential pressure release.

Acid pneumonitis is a major cause of sterile acute lung injury (ALI) in humans. Acid pneumonitis spans the clinical spectrum from asymptomatic to acute ...

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 ...

Inducing Acute Lung Injury in Mice by Direct Intratracheal Lipopolysaccharide Instillation

Airway administration of lipopolysaccharide (LPS) is a common way to study pulmonary inflammation and acute lung injury (ALI) in small animal models. Various approaches have been described, such as the inhalation of aerosolized LPS as well as nasal or intratracheal instillation. The presented protocol describes a detailed step-by-step procedure to induce ALI in mice by direct intratracheal LPS instillation and perform FACS analysis of blood samples, bronchoalveolar lavage (BAL) fluid, and lung tissue. After intraperitoneal sedation, the trachea is exposed and LPS is administered via a 22 G venous catheter. A robust and reproducible inflammatory reaction with leukocyte invasion, upregulation of proinflammatory cytokines, and disruption of the alveolo-capillary barrier is induced within hours to days, depending on the LPS dosage used. Collection of blood samples, BAL fluid, and lung harvesting, as well as the processing for FACS analysis, are described in detail in the protocol. Although the use of the sterile LPS is not suitable to study pharmacologic interventions in infectious diseases, the described approach offers minimal invasiveness, simple handling, and good reproducibility to answer mechanistic immunological questions. Furthermore, dose titration as well as the use of alternative LPS preparations or mouse strains allow modulation of the clinical effects, which can exhibit different degrees of ALI severity or early vs. late onset of disease symptoms.

Presented here is a step-by-step procedure to induce acute lung injury in mice by direct intratracheal lipopolysaccharide instillation and to perform FACS analysis of blood samples, bronchoalveolar lavage fluid, and lung tissue. Minimal invasiveness, simple handling, good reproducibility, and titration of disease severity are advantages of this approach.

Airway administration of lipopolysaccharide (LPS) is a common way to study pulmonary inflammation and acute lung injury (ALI) in small animal models. ...

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 ...