Name: two-vessel occlusion mouse model of cerebral ischemia-reperfusion
Uploaded: 2019-03-01T13:30:00
Description: Watch this Scientific Journal Video about Two-vessel Occlusion Mouse Model of Cerebral Ischemia-reperfusion at JoVE.com

This work was supported by the Ministry of Science and Technology, Taiwan (MOST 106-2320-B-038-024, MOST 105-2221-E-038-007-MY3, and MOST 104-2320-B-424-001) and Taipei Medical University Hospital (107TMUH-SP-01). This manuscript was edited by Wallace Academic Editing.

The institutional animal care and use committees of Academia Sinica and Taipei Medical University approved this protocol for the use of experimental animals.
1. MCAO/reperfusion model
<ol>
	<li>Provide the mice with free access to water and chow until the surgery.</li>
	<li>Autoclave the surgical tools and sanitize the surgery table and equipment using 70% ethanol. Wear a surgical mask and sterile gloves. Use a dry bead sterilizer to resterilize the surgical tools if multiple mouse surgeries...

<ol>
	<li>Woodruff, T. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pathophysiology,+treatment,+and+animal+and+cellular+models+of+human+ischemic+stroke.">Pathophysiology, treatment, and animal and cellular models of human ischemic stroke.</a> Molecular Neurodegeneration. 6 (1), 11 (2011).</li><li>Chamorro, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+immunology+of+acute+stroke.">The immunology of acute stroke.</a> Nature Reviews. Neurology. 8 (7), 401-410 (2012).</li><li>Engel, O., Kolodziej, S., Dirnagl, U., Prinz, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+stroke+in+mice+-+Middle+cerebral+artery+occlusion+with+the+filament+model.">Modeling stroke in mice - Middle cerebral artery occlusion with the filament model.</a> Journal of Visualized Experiments. (47), e2423 (2011).</li><li>Lee, G. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interleukin+15+blockade+protects+the+brain+from+cerebral+ischemia-reperfusion+injury.">Interleukin 15 blockade protects the brain from cerebral ischemia-reperfusion injury.</a> Brain, Behavior, and Immunity. 73, 562-570 (2018).</li><li>Barone, F. C., Knudsen, D. J., Nelson, A. H., Feuerstein, G. Z., Willette, R. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+strain+differences+in+susceptibility+to+cerebral+ischemia+are+related+to+cerebral+vascular+anatomy.">Mouse strain differences in susceptibility to cerebral ischemia are related to cerebral vascular anatomy.</a> Journal of Cerebral Blood Flow and Metabolism: Official Journal of the International Society of Cerebral Blood Flow and Metabolism. 13 (4), 683-692 (1993).</li><li>Kitagawa, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cerebral+ischemia+after+bilateral+carotid+artery+occlusion+and+intraluminal+suture+occlusion+in+mice:+evaluation+of+the+patency+of+the+posterior+communicating+artery.">Cerebral ischemia after bilateral carotid artery occlusion and intraluminal suture occlusion in mice: evaluation of the patency of the posterior communicating artery.</a> Journal of Cerebral Blood Flow and Metabolism: Official Journal of the International Society of Cerebral Blood Flow and Metabolism. 18 (5), 570-579 (1998).</li><li>Wellons, J. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+comparison+of+strain-related+susceptibility+in+two+murine+recovery+models+of+global+cerebral+ischemia.">A comparison of strain-related susceptibility in two murine recovery models of global cerebral ischemia.</a> Brain Research. 868 (1), 14-21 (2000).</li><li>Doyle, K. P., Fathali, N., Siddiqui, M. R., Buckwalter, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Distal+hypoxic+stroke:+a+new+mouse+model+of+stroke+with+high+throughput,+low+variability+and+a+quantifiable+functional+deficit.">Distal hypoxic stroke: a new mouse model of stroke with high throughput, low variability and a quantifiable functional deficit.</a> Journal of Neuroscience Methods. 207 (1), 31-40 (2012).</li><li>Doyle, K. P., Buckwalter, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+mouse+model+of+permanent+focal+ischemia:+Distal+middle+cerebral+artery+occlusion.">A mouse model of permanent focal ischemia: Distal middle cerebral artery occlusion.</a> Methods in Molecular Biology. , 103-110 (2014).</li><li>Wayman, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Performing+Permanent+Distal+Middle+Cerebral+with+Common+Carotid+Artery+Occlusion+in+Aged+Rats+to+Study+Cortical+Ischemia+with+Sustained+Disability.">Performing Permanent Distal Middle Cerebral with Common Carotid Artery Occlusion in Aged Rats to Study Cortical Ischemia with Sustained Disability.</a> Journal Of Visualized Experiments. (108), e53106 (2016).</li><li>Noor, R., Wang, C. X., Shuaib, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+hyperthermia+on+infarct+volume+in+focal+embolic+model+of+cerebral+ischemia+in+rats.">Effects of hyperthermia on infarct volume in focal embolic model of cerebral ischemia in rats.</a> Neuroscience Letters. 349 (2), 130-132 (2003).</li><li>Florian, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long-term+hypothermia+reduces+infarct+volume+in+aged+rats+after+focal+ischemia.">Long-term hypothermia reduces infarct volume in aged rats after focal ischemia.</a> Neuroscience Letters. 438 (2), 180-185 (2008).</li><li>Carmichael, S. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rodent+models+of+focal+stroke:+size,+mechanism,+and+purpose.">Rodent models of focal stroke: size, mechanism, and purpose.</a> NeuroRx: The Journal of the American Society for Experimental NeuroTherapeutics. 2 (3), 396-409 (2005).</li><li>Lin, T. N., Te, J., Huang, H. C., Chi, S. I., 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=Prolongation+and+enhancement+of+postischemic+c-fos+expression+after+fasting.">Prolongation and enhancement of postischemic c-fos expression after fasting.</a> Stroke. 28 (2), 412-418 (1997).</li><li>Glazier, S. S., O'Rourke, D. M., Graham, D. I., Welsh, F. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induction+of+ischemic+tolerance+following+brief+focal+ischemia+in+rat+brain.">Induction of ischemic tolerance following brief focal ischemia in rat brain.</a> Journal of Cerebral Blood Flow and Metabolism: Official Journal of the International Society of Cerebral Blood Flow and Metabolism. 14 (4), 545-553 (1994).</li><li>Tachibana, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+Reperfusion+After+Brain+Ischemia+Has+Beneficial+Effects+Beyond+Rescuing+Neurons.">Early Reperfusion After Brain Ischemia Has Beneficial Effects Beyond Rescuing Neurons.</a> Stroke. 48 (8), 2222-2230 (2017).</li><li>Gan, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ischemic+neurons+recruit+natural+killer+cells+that+accelerate+brain+infarction.">Ischemic neurons recruit natural killer cells that accelerate brain infarction.</a> Proceedings of the National Academy of Sciences of the United States of America. 111 (7), 2704-2709 (2014).</li><li>Li, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Astrocyte-derived+interleukin-15+exacerbates+ischemic+brain+injury+via+propagation+of+cellular+immunity.">Astrocyte-derived interleukin-15 exacerbates ischemic brain injury via propagation of cellular immunity.</a> Proceedings of the National Academy of Sciences of the United States of America. 114 (3), E396-E405 (2017).</li><li>Wang, S., Zhang, H., Dai, X., Sealock, R., Faber, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+architecture+underlying+variation+in+extent+and+remodeling+of+the+collateral+circulation.">Genetic architecture underlying variation in extent and remodeling of the collateral circulation.</a> Circulation Research. 107 (4), (2010).</li></ol>

The MCAO/reperfusion mouse model is an animal model commonly employed to mimic transient ischemia in humans. This animal model can be applied to transgenic and knockout mice strains to investigate the pathophysiology of stroke. Several steps in the protocol are especially critical. (1) The microdrill must be carefully used when creating a hole in the skull, with inappropriate action easily causing bleeding from the MCA. (2) The MCA should not be damaged, and bleeding must be avoided before and after the ligation procedur...

The cerebral ischemia-reperfusion mouse model is one of the most widely used experimental approaches for investigating the pathophysiology of ischemia-induced brain injury1. Because cerebral ischemia-reperfusion activates the peripheral immune system, peripheral immune cells infiltrate into the ischemic brain and cause neuronal damage2. Thus, a reliable and reproducible mouse model that mimics cerebral ischemia-reperfusion is required to understand the pathophysiology of stroke.
C57BL/6J (B6) mice are the most commonly used strain in stroke experiments because they can easily be genetically manipulated. Two common models of MCAO/reperfusion that mimic the condition of cerebral ischemia-reperfusion are available. The first is the intraluminal filament model of proximal MCAO, where a silicon-coated filament is employed to intravascularly occlude the blood flow in the MCA; the occluding filament is subsequently removed to restore blood flow3. A short occlusion duration results in a lesion of the subcortical region, whereas a longer occlusion duration causes infarcts in the cortical and subcortical areas. The second model is the ligation model of distal MCAO, which involves extravascular ligation of the MCA and CCA to reduce the blood flow through the MCA, after which blood flow is restored through the removal of the suture and aneurysm clip4. In this model, an infarct is caused in the cortical areas, and the mortality rate is low. Because the ligation of MCAO/reperfusion model requires craniectomy to expose the site of the distal MCA, the site can be easily confirmed, and examining whether the blood flow in the distal MCA is disrupted during the procedure is straightforward.
B6 mice exhibit considerable variations in the anatomy of their circle of Willis; this might affect the infarct volume following cerebral ischemia-reperfusion5,6,7. Currently, this problem can be overcome through ligation of the distal MCA8. In this study, we establish a method for occluding the MCA blood flow and enabling reperfusion after a predetermined period of ischemia. Two-vessel occlusion of the cerebral ischemia-reperfusion model induces transient ischemia of the MCA territory through ligation of the right distal MCA and right CCA, with blood flow restored after a certain period of ischemia.This MCAO/reperfusion model induces an infarct of stable size, a bulk of brain-infiltrating immune cells in the ischemic brain, and a behavioral deficit after cerebral ischemia&#8211;reperfusion4.

<table>
	<tbody>
		<tr>
			<td>Bone rongeur</td>
			<td>Diener</td>
			<td></td>
			<td>Friedman</td>
		</tr>
		<tr>
			<td>Buprenorphine</td>
			<td>Sigma</td>
			<td>B-044</td>
			<td></td>
		</tr>
		<tr>
			<td>Cefazolin</td>
			<td>Sigma</td>
			<td>1097603</td>
			<td></td>
		</tr>
		<tr>
			<td>Chloral hydrate</td>
			<td>Sigma</td>
			<td>C8383</td>
			<td></td>
		</tr>
		<tr>
			<td>Dissection microscope</td>
			<td>Nikon</td>
			<td>SMZ-745</td>
			<td></td>
		</tr>
		<tr>
			<td>Electric clippers</td>
			<td>Petpro</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>10% formalin</td>
			<td>Sigma</td>
			<td>F5304</td>
			<td></td>
		</tr>
		<tr>
			<td>Germinator dry bead sterilizer</td>
			<td>Braintree Scientific</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Iris Forceps</td>
			<td>Karl Klappenecker</td>
			<td></td>
			<td>10 cm</td>
		</tr>
		<tr>
			<td>Iris Scissors</td>
			<td>Diener</td>
			<td></td>
			<td>9 cm</td>
		</tr>
		<tr>
			<td>Iris Scissors STR</td>
			<td>Karl Klappenecker</td>
			<td></td>
			<td>11 cm</td>
		</tr>
		<tr>
			<td>Microdrill</td>
			<td>Stoelting</td>
			<td>FOREEDOM K.1070</td>
			<td></td>
		</tr>
		<tr>
			<td>Micro-scissors-Vannas</td>
			<td>HEISS</td>
			<td>H-4240</td>
			<td>blade 7mm, 8 cm</td>
		</tr>
		<tr>
			<td>Mouse brain matrix</td>
			<td>World Precision Instruments</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Non-invasive blood pressure system</td>
			<td>Muromachi</td>
			<td>MK-2000ST</td>
			<td></td>
		</tr>
		<tr>
			<td>Operating Scissors STR</td>
			<td>Karl Klappenecker</td>
			<td></td>
			<td>14 cm</td>
		</tr>
		<tr>
			<td>Physiological Monitoring System</td>
			<td>Harvard Apparatus</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Razor blades</td>
			<td>Ever-Ready</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Stoelting Rodent Warmers</td>
			<td>Stoelting</td>
			<td>53810</td>
			<td>Heating pad</td>
		</tr>
		<tr>
			<td>Suture clip</td>
			<td>Stoelting</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Tweezers</td>
			<td>IDEALTEK</td>
			<td></td>
			<td>No.3</td>
		</tr>
		<tr>
			<td>Vetbond</td>
			<td>3M</td>
			<td>15672</td>
			<td>Surgical glue</td>
		</tr>
		<tr>
			<td>10-0 suture</td>
			<td>UNIK</td>
			<td>NT0410</td>
			<td></td>
		</tr>
		<tr>
			<td>2,3,5-Triphenyltetrazolium chloride</td>
			<td>Sigma</td>
			<td>T8877</td>
			<td></td>
		</tr>
	</tbody>
</table>

two-vessel occlusion mouse model of cerebral ischemia-reperfusion

In this study, a middle cerebral artery (MCA) occlusion mouse model is employed to study cerebral ischemia-reperfusion. A reproducible and reliable mouse model is useful for investigating the pathophysiology of cerebral ischemia-reperfusion and determining potential therapeutic strategies for patients with stroke. Variations in the anatomy of the circle of Willis of C57BL/6 mice affects their infarct volume after cerebral-ischemia-induced injury. Studies have indicated that distal MCA occlusion (MCAO) can overcome this problem and result in a stable infarct size. In this study, we establish a two-vessel occlusion mouse model of cerebral ischemia-reperfusion through the interruption of the blood flow to the right MCA. We distally ligate the right MCA and right common carotid artery (CCA) and restore blood flow after a certain period of ischemia. This ischemia-reperfusion injury induces an infarct of stable size and a behavioral deficit. Peripheral immune cells infiltrate the ischemic brain within the 24 h infiltration period. Additionally, the neuronal loss in the cortical area is less for a longer reperfusion duration. Therefore, this two-vessel occlusion model is suitable for investigating the immune response and neuronal recovery during the reperfusion period after cerebral ischemia.

This MCAO/reperfusion procedure produced a cortical infarct in the vicinity of the right MCA and caused a behavioral deficit. Different degrees of ischemia-induced infarct volume (Figure 1A,B) and neuronal loss (Figure 1C,D) were created in the cerebral cortex of the right MCA area through an increase in ligation duration. This MCAO/reperfusion injury decreased the animal&#39;s locomotor activity...

Watch this Scientific Journal Video about Two-vessel Occlusion Mouse Model of Cerebral Ischemia-reperfusion at JoVE.com

Two-vessel Occlusion Mouse Model of Cerebral Ischemia-reperfusion

A mouse model of cerebral ischemia-reperfusion is established to investigate the pathophysiology of stroke. We distally ligate the right middle cerebral artery and right common carotid artery and restore blood flow after 10 or 40 min of ischemia.

In this study, a middle cerebral artery (MCA) occlusion mouse model is employed to study cerebral ischemia-reperfusion. A reproducible and reliable mouse ...

This two-vessel occlusion mouse model of cerebral ischemia-reperfusion can investigate the pathophysiology of stroke. This model will induce a stable infarct volume of bulk of brain infiltrating immune cells in the ischemic brain and the behavioral deficit after cerebral ischemia-reperfusion. In this model, an infarct is caused in the cortical areas and the mortality rate is low.Because the ligation MCAO reperfusion model requires craniotomy to expose the size of distal MCA, the size can be easily confirmed, and the exam whether the blood flow in the distal MCAO is disrupted during the procedure is straightforward. Provide the mice with free access to water and food until the surgery. Autoclave the surgical tools, and use 70%ethanol to sanitize the surgery table and equipment.After anesthetizing an eight to 12-week-old mouse, make sure that it does not have a pedal reflex when tested using a firm toe pinch. Use vet ointment to prevent eye dryness while the mouse is under anesthesia. To monitor the blood pressure, first remove the hair, and then use a non-invasive blood pressure system and a physiological monitoring system to monitor rectal temperature and arterial blood gasses.Inject the mouse subcutaneously with a prophylactic antibiotic. Next, place the mouse in the supine position on the heating pad. To expose the skin, use electric clippers to shave the fur on the ventral neck region and in the region between the right eye and right ear.Clear the fur from the animal's body with epilating cream, and disinfect the surgical site with 70%ethanol. Then cut a one-centimeter-long midline incision at the neck using iris scissors. With iris forceps, carefully dissect the common carotid artery free from the vagus nerves without causing physical injury, and use 5-0 silk sutures to isolate the artery.Next, use iris scissors to make a 0.3-centimeter incision in the scalp at the midpoint between the right eye and right ear. Using micro scissors, cut the temporalis muscle to expose the zygomatic and squamosal bone. Place the mouse under a stereo dissecting microscope, and use a micro drill to create a two milliliter hole directly over the right-side distal middle cerebral artery.Use a 10-0 suture to ligate the trunk of the right-side distal MCA, and use a nontraumatic aneurism clip to occlude the right-side CCA. After desired duration of ischemia, remove the suture and aneurism clip to restore blood flow to the MCA and CCA. Use a suture clip to seal the skin incision on the head and seal the cervical skin incisions with surgical glue.Inject buprenorphine subcutaneously for pain relief. Maintain the animal's body temperature at 36.5 plus or minus 0.5 degrees Celsius on the heating pad, and do not leave unattended or return it to the company of other animals until it is fully recovered from the anesthesia. Finally, place the mouse into the autoclave cage so that it can freely access water and food after it has fully recovered.Use iris scissors to make an incision in the skin of the head of the anesthetized and decapitated mouse to expose the skull. Then use operating scissors to cut the anterior of the frontal bone, and with iris scissors, cut the skull along the sagittal suture. With a bone rongeur, push aside the frontal and parietal bone, and expose the brain.Remove the brain, and place it in a mouse brain matrix. Use razor blades to obtain two-milliliter coronal slices, and place them in 50-milliliter tubes filled with five milliliters of 2%TTC. When using mouse brain matrix to obtain coronal slices, the cutting size should be same in different brains.Cutting size affect the size of brain slices, which also affect the calculation of infarct size. Stain the brain slices with 2%TTC and 1X PBS for 10 minutes at 37 degrees Celsius, and then rinse two times with 10%formalin. Fix the brain slices in 10%formalin at room temperature for 24 hours.After drying the brain slices on the tissue paper to absorb excess formalin, arrange them on a clean plastic slide, orienting them from rostral to caudal, and cover them with another clean plastic slide. Scan the slide using a scanner. Flip the slide over, and scan the reverse side.Use ImageJ software to calculate the infarction area of each section, by first opening the image file and setting up the scale for the image. Then use freehand selection to select the infarct area, and use the regions of interest ROI manager to measure the area of interest. Finally, sum the infarct areas for each section, and multiply the result by the section thickness to estimate the total infarction volume, and then complete statistical analysis as described in the manuscript.Increase in ischemia duration during this MCAO reperfusion procedure produced different degrees of ischemia-induced infarct volume and neuronal loss in the cerebral cortex of the right MCA area. Furthermore, the ischemia decreased the animal's locomotor activity at 48 hours after the MCAO reperfusion. After the cerebral ischemia-reperfusion, a bulk of peripheral immune cells infiltrated the ipsilateral hemisphere of the ischemic brain.In addition, when this two-vessel occlusion model was compared with the MCAO model, their infarct volumes were not significantly different. The micro drill must be carefully used when creating a hole in the skull. With inappropriate action, easy causing bleeding from the MCA.The MCA should not be damaged, and the bleeding must be avoided before and after the ligation procedure. The MCA occlusion and the reperfusion status can be checked by the laser Doppler. This method can confirm the condition of the blood flow of MCA.

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Medicine

Mouse Model of Middle Cerebral Artery Occlusion

Stroke is the most common fatal neurological disease in the United States 1. The majority of strokes (88%) result from blockage of blood vessels in the brain (ischemic stroke) 2. Since most ischemic strokes (~80%) occur in the territory of middle cerebral artery (MCA) 3, many animal stroke models that have been developed have focused on this artery. The intraluminal monofilament model of middle cerebral artery occlusion (MCAO) involves the insertion of a surgical filament into the external carotid artery and threading it forward into the internal carotid artery (ICA) until the tip occludes the origin of the MCA, resulting in a cessation of blood flow and subsequent brain infarction in the MCA territory 4. The technique can be used to model permanent or transient occlusion 5. If the suture is removed after a certain interval (30 min, 1 h, or 2 h), reperfusion is achieved (transient MCAO); if the filament is left in place (24 h) the procedure is suitable as a model of permanent MCAO. This technique does not require craniectomy, a neurosurgical procedure to remove a portion of skull, which may affect intracranial pressure and temperature 6. It has become the most frequently used method to mimic permanent and transient focal cerebral ischemia in rats and mice 7,8. To evaluate the extent of cerebral infarction, we stain brain slices with 2,3,5-triphenyltetrazolium chloride (TTC) to identify ischemic brain tissue 9. In this video, we demonstrate the MCAO method and the determination of infarct size by TTC staining.

We demonstrate in the video a method for producing a middle cerebral artery occlusion in adult mice using an intraluminal monofilament. We also show how to evaluate the extent of cerebral infarction by 2,3,5-triphenyltetrazolium chloride (TTC) staining.

Stroke is the most common fatal neurological disease in the United States 1. The majority of strokes (88%) result from blockage of blood vessels in the ...

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 ...

Stem Cell Transplantation in an in vitro Simulated Ischemia/Reperfusion Model

Stem cell transplantation protocols are finding their way into clinical practice1,2,3. Getting better results, making the protocols more robust, and finding new sources for implantable cells are the focus of recent research4,5. Investigating the effectiveness of cell therapies is not an easy task and new tools are needed to investigate the mechanisms involved in the treatment process6. We designed an experimental protocol of ischemia/reperfusion in order to allow the observation of cellular connections and even subcellular mechanisms during ischemia/reperfusion injury and after stem cell transplantation and to evaluate the efficacy of cell therapy. H9c2 cardiomyoblast cells were placed onto cell culture plates7,8. Ischemia was simulated with 150 minutes in a glucose free medium with oxygen level below 0.5%. Then, normal media and oxygen levels were reintroduced to simulate reperfusion. After oxygen glucose deprivation, the damaged cells were treated with transplantation of labeled human bone marrow derived mesenchymal stem cells by adding them to the culture. Mesenchymal stem cells are preferred in clinical trials because they are easily accessible with minimal invasive surgery, easily expandable and autologous. After 24 hours of co-cultivation, cells were stained with calcein and ethidium-homodimer to differentiate between live and dead cells. This setup allowed us to investigate the intercellular connections using confocal fluorescent microscopy and to quantify the survival rate of postischemic cells by flow cytometry. Confocal microscopy showed the interactions of the two cell populations such as cell fusion and formation of intercellular nanotubes. Flow cytometry analysis revealed 3 clusters of damaged cells which can be plotted on a graph and analyzed statistically. These populations can be investigated separately and conclusions can be drawn on these data on the effectiveness of the simulated therapeutical approach.

Stem Cell Transplantation in an in vitro Simulated Ischemia/Reperfusion Model

We demonstrate how to set up an in vitro ischemia/reperfusion model and how to evaluate the effect of stem cell therapy on postischemic cardiac cells.

Stem cell transplantation protocols are finding their way into clinical practice1,2,3. Getting better results, making the protocols more robust, and ...

Optimized System for Cerebral Perfusion Monitoring in the Rat Stroke Model of Intraluminal Middle Cerebral Artery Occlusion

The translational potential of pre-clinical stroke research depends on the accuracy of experimental modeling. Cerebral perfusion monitoring in animal models of acute ischemic stroke allows to confirm successful arterial occlusion and exclude subarachnoid hemorrhage. Cerebral perfusion monitoring can also be used to study intracranial collateral circulation, which is emerging as a powerful determinant of stroke outcome and a possible therapeutic target. Despite a recognized role of Laser Doppler perfusion monitoring as part of the current guidelines for experimental cerebral ischemia, a number of technical difficulties exist that limit its widespread use. One of the major issues is obtaining a secure and prolonged attachment of a deep-penetration Laser Doppler probe to the animal skull. In this video, we show our optimized system for cerebral perfusion monitoring during transient middle cerebral artery occlusion by intraluminal filament in the rat. We developed in-house a simple method to obtain a custom made holder for twin-fibre (deep-penetration) Laser Doppler probes, which allow multi-site monitoring if needed. A continuous and prolonged monitoring of cerebral perfusion could easily be obtained over the intact skull.

Cerebral perfusion monitoring has been demonstrated to improve accuracy in ischemic stroke models. Technical difficulties often limit the use of this essential tool for cerebrovascular research. In this video, an optimized system is shown to obtain a single or multi-site hemodynamic monitoring during intraluminal middle cerebral artery occlusion in rats.

The translational potential of pre-clinical stroke research depends on the accuracy of experimental modeling. Cerebral perfusion monitoring in animal ...

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 ...

Reproducable Paraplegia by Thoracic Aortic Occlusion in a Murine Model of Spinal Cord Ischemia-reperfusion

Background 
Lower extremity paralysis continues to complicate aortic interventions. The lack of understanding of the underlying pathology has hindered advancements to decrease the occurrence this injury.&#160;The current model demonstrates reproducible lower&#160;extremity paralysis following thoracic aortic occlusion.
Methods 
Adult male C57BL6 mice were anesthetized with isoflurane. Through a cervicosternal incision the aorta was exposed. The descending thoracic aorta and left subclavian arteries were identified without entrance into pleural space. Skeletonization of these arteries was followed by immediate closure (Sham) or occlusion for 4 min (moderate ischemia) or 8 min (prolonged ischemia). The sternotomy and skin were closed and the mouse was transferred to warming bed for recovery.&#160; Following recovery, functional analysis was obtained at 12 hr intervals until 48 hr.
Results 
Mice that underwent sham surgery showed no observable hind&#160;limb deficit. Mice subjected to moderate ischemia for 4 min had minimal functional deficit at 12 hr followed by progression to complete paralysis at 48 hr. Mice subjected to prolonged ischemia had an immediate paralysis with no observable hind-limb movement at any point in the postoperative period. There was no observed intraoperative or post&#160;operative mortality.
Conclusion 
Reproducible lower extremity paralysis whether immediate or delayed can be achieved in a murine model. Additionally, by using a median sternotomy and careful dissection, high survival rates, and reproducibility can be achieved.

The lack of mechanistic understanding of spinal cord ischemia-reperfusion injury has hindered further adjuncts to prevent paraplegia following high risk aortic operations. Thus, the development of animal models is imperative. This manuscript demonstrates reproducible lower extremity paralysis following thoracic aortic occlusion in a murine model.

Background
Lower extremity paralysis continues to complicate aortic interventions. The lack of understanding of the underlying pathology has hindered ...

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, ...

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 ...

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 ...