This work was supported by Research Excellence Program-UConn Health (to Ketan R Bulsara and Rajkumar Verma) and UConn Health start-up (to Rajkumar Verma).

All experiments were approved by the Institutional Animal Care and Use Committee of UConn Health and conducted in accordance with US guidelines. The following protocol should work in any species or strain of rodent. Here, 8- to 12-week-old, age- and weight-matched C57BL/6 wild-type male mice were used. Mice were fed standard chow diet and water ad libitum. Standard housing conditions were maintained at 72.3 &#176;F&#160;and 30%-70% relative humidity with a 12 h light/dark cycle.
1. Pre-surgery preparation
<ol>
	<li>Sterilize all instruments by autoclaving prior to surgery. Sanitize the operating surface with 70% ethanol and warm the operating surface to 37 &#176;C with an electric heating pad.</li>
	<li>Use an induction chamber to anesthetize the mouse with 4%-5% isoflurane for induction. Deliver 1.5%-2.0% isoflurane via nose cone for maintenance until the end of surgery. Ensure prior to surgery that the mouse is properly anesthetized by assessing the lack of a response to a firm hind foot pinch and loss of the postural reaction and righting reflex.</li>
	<li>Place the mouse on its left side on the operating surface and apply eye ointment to protect both eyes.</li>
	<li>Shave hair over the surgical field (i.e., right lateral cranium between eye and ear) with&#160;electric clippers. Clean the surgical field&#160;in concentric circles outward from the middle of the surgical site,&#160;with 70% ethanol followed by povidone solution, and repeat these steps 2x. 
	NOTE:&#160;Due to the surgery site being close to the eye, removing 150% of the area surrounding a surgical site may not be possible to avoid irritation or accidental injury to the eye.</li>
	<li>Administer a single dose of 0.25% bupivacaine (up to 8 mg/kg body weight) by subcutaneous injection as pre-operative analgesia at the site of surgery.</li>
	<li>Set up a surgical microscope at 4x magnification. The microscope is used for all surgical steps.</li>
</ol>
2. Surgery procedure
NOTE: The surgery steps are presented in Figure 1. For this protocol, three mice were allocated to sham group, three mice for EMS alone, 12 mice for MCAo, and 23 mice for MCAo + EMS group.
<ol>
	<li>MCAo surgery 
	NOTE: MCAo is a well-characterized model of ischemic stroke in rodents, as described by us and others12,13,14. The surgery steps are described in brief here. Focal transient cerebral ischemia was induced by a 60 min right MCAo under isoflurane anesthesia followed by reperfusion for 7 or 21 days.
	<ol>
		<li>Make a midline ventral neck incision followed by unilateral right MCAo by advancing a 10-11 mm long 6.0 silicone rubber-coated monofilament from the internal carotid artery bifurcation via an external carotid artery stump. In sham mice, perform identical surgeries except for the advancement of the suture into the internal carotid artery.</li>
		<li>Measure rectal temperatures using a temperature control system, maintaining the temperature at ~37 &#176;C during surgery with an automatic heating pad.</li>
		<li>Use laser Doppler flowmetry to measure cerebral blood flow prior to suture insertion by placing the Doppler probe against the lateral skull (corresponding to the MCA territory) and recording the value8. To confirm occlusion reduction to 15% of baseline cerebral blood flow, use the same procedure after the suture is advanced. To confirm reperfusion, use the same procedure after the suture is removed.</li>
		<li>Feed all animals with wet mash until sacrifice and/or 1 week after surgery to ensure adequate nutrition for chronic endpoints, as animals have rearing deficits after stroke.</li>
	</ol>
	</li>
	<li>EMS surgery
	<ol>
		<li>After 60 min of MCAo, randomize mice into MCAo-only or MCAo + EMS groups. Perform EMS 4 h after MCAo (MCAo + EMS group) or sham surgery for select experiments (EMS-only group). Change into a new pair of sterile surgical gloves before the surgery. 
		NOTE: The mice recovered from anesthesia after 60 minutes of&#160;MCAo and were re-anesthetized before the EMS surgery.</li>
		<li>For groups that receive EMS (MCAo + EMS or EMS-only groups), make a 10-15 mm skin incision with scissors, extending from 1-2 mm rostral to the right ear to 1-2 mm caudal to the right eye. 
		NOTE: Sterile scissors were used to prevent accidental damage to the temporalis muscles underneath.</li>
		<li>Retract skin flaps using clamps and visually identify the temporalis muscle and the skull.</li>
		<li>Bluntly dissect the temporalis muscle away from the skull using scissors with a spreading technique. Perform a 2-3 mm myotomy directed ventrally along the caudal border of the muscle to facilitate ventral reflection.</li>
		<li>Perform a craniotomy ~5 mm in diameter at the skull underneath the reflected temporalis muscle using a micro drill.</li>
		<li>Remove the dura mater with tweezers to expose the pial surface of the brain. Use extreme caution to avoid accidental injury to the brain.</li>
		<li>Suture the dorsal border of the temporalis muscle to the subcutaneous tissue of the dorsal skin flap with 6-0 monocryl filaments, making it flush to the exposed cerebral cortex.</li>
		<li>Close the skin incision with 6-0 monofilament suture. Place the mouse back into its cage and monitor until recovery from anesthesia. Return the mouse to its housing facility.</li>
	</ol>
	</li>
</ol>
3. Post-operative considerations
<ol>
	<li>Monitor the mice for illness and the surgical site for infection daily. Give subcutaneous normal saline (1% volume by body weight) daily to support hydration.</li>
	<li>Monitor for severe dehydration (loss of body weight &#62;20%) until 7 days after surgery. Administer an additional bolus of subcutaneous normal saline 1% volume by body weight if &#62;20% weight loss.</li>
	<li>Proceed with injections, physiologic monitoring, and other testing without special considerations. 
	NOTE: In this procedure, the use of opioids or non-steroidal anti-inflammatory drugs (NSAIDs) to treat post-surgery was avoided due to the known effects of these agents on stroke outcome or infarct size in consultation with in-house institutional animal care and use committee15,16,17,18. However, the use of post-operative analgesia is highly encouraged for EMS surgery with other models. Please consult the Institutional Animal Care and Use Committee (IACUC) for this.</li>
</ol>

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The authors have no conflicts of interest to disclose.

This protocol describes a successful EMS procedure in a mouse model of MCAo-induced stroke. The data show that grafted tissue remains viable and can form bonds with brain cortex long after EMS surgery. These findings support the rationale for using a cerebral muscle graft to gradually develop a richly vascular trophic environment at the site of stroke. EMS is a promising therapy for potentially repairing infarcted cerebral tissue in the same environment.
The critical steps of the protocol incl...

Ischemic stroke is an acute neurovascular injury with devastating chronic sequelae. Most of the stroke survivors, 650,000 per year, in the US suffer from permanent functional disability1. None of the available treatments confer neuroprotection and functional recovery after the acute phase of ischemic stroke. After an acute ischemic stroke, both direct and collateral blood supplies are diminished which leads to dysfunction of brain cells and networks, resulting in sudden neurological deficits2,3. Restoration of blood supply to the ischemic region remains the foremost goal of stroke therapy. Thus, enhancing angiogenesis to promote blood supply in the ischemic territory is a promising therapeutic approach; however, previously studied methods for promoting post-stroke angiogenesis, including erythropoietin, statins, and growth factors, have been limited by unacceptable levels of toxicity or translatability4.
Encephalomyosynangiosis (EMS) is a surgical procedure that enhances cerebral angiogenesis in humans with moyamoya disease, a condition of narrowed cranial arteries that often leads to stroke. EMS involves partial detachment of a vascular section of the patient's temporalis muscle from the skull, followed by craniotomy and grafting of the muscle onto the affected cortex. This procedure is well tolerated and induces cerebral angiogenesis, reducing the risk of ischemic stroke in patients with moyamoya disease5,6. Thus, the procedure serves largely a preventative role in these patients. The angiogenesis brought about by this procedure may also have a role in promoting neurovascular protection and recovery in the setting of ischemic stroke. This report supports the hypothesis that angiogenesis brought about by EMS has the potential to expand the understanding of and therapeutic options for cerebral ischemia.
Beside EMS, there are several pharmacological and surgical approaches to improve angiogenesis, but they have several limitations. Pharmacological approaches such as vascular endothelial growth factor (VEGF) administration has been found to be insufficient or even detrimental due to several limitations, including the formation of chaotic, disorganized, leaky, and primitive vascular plexuses, which resemble those found in the tumor tissues7,8 and have no beneficial effects in clinical trials9. 
Surgical approaches include direct anastomosis such as superficial temporal artery-middle cerebral artery anastomosis, indirect anastomosis such as encephalo-duro arterio-synangiosis (EDAS), encephalomyosynangiosis (EMS), and combinations of direct and indirect anastomosis10. All these procedures are very technically challenging and demanding in small animals, except for EMS. Whereas the other procedures require complex vascular anastomosis, EMS requires a relatively simple muscle graft. Moreover, the proximity of the temporalis muscle to the cortex makes it a natural choice for grafting, as it does not need to be completely excised or disconnected from its blood supply, as would be necessary if a more distant muscle were used for grafting. 
EMS has been studied in chronic cerebral hypoperfusion models in rats7,11. However, EMS using a temporalis muscle graft has never been studied in acute ischemic stroke in rodents. Here, we describe a novel protocol of EMS in mice after an ischemic stroke via middle cerebral artery occlusion model (MCAo). This manuscript serves as a description of methods and early data for this novel approach of EMS in mice after MCAo.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>6-0 monocryl suture</td>
			<td>Ethilon</td>
			<td>697G</td>
			<td></td>
		</tr>
		<tr>
			<td>70% ethanol to sanitize operating surface</td>
			<td>Walgreen</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Bupivacaine 0.25% solution</td>
			<td>Midwest Vet</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Clamps for tissue retraction</td>
			<td>Roboz</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Doccal suture with Nylon coating</td>
			<td>Doccal corporation Sharon MA</td>
			<td>602145PK10Re</td>
			<td></td>
		</tr>
		<tr>
			<td>Electric heating pad for operating surface</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane anesthesia</td>
			<td>Piramal Critical Care Inc</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane delivery apparatus</td>
			<td>--B6Surgivet (Isotech 4)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Micro drill</td>
			<td>Harvard Apparatus</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Microdissecting tweezers, curved x2</td>
			<td>Piramal Critical Care Inc</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>mouse angiogenesis panel arrat</td>
			<td>R&#38; D biotech</td>
			<td>ARY015</td>
			<td></td>
		</tr>
		<tr>
			<td>Needle driver</td>
			<td>Ethilon</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ointment for eye protection</td>
			<td>walgreen</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Operating microscope</td>
			<td>Olympus</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Operating surface</td>
			<td>Olympus</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Povidone iodine solution</td>
			<td>walgreen</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Rectal thermometer</td>
			<td>world precison instrument</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Saline or 70% ethanol for irrigation</td>
			<td>walgreen</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Small electric razor to shave operative site</td>
			<td>generic</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical scissors</td>
			<td>Roboz</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

a model for encephalomyosynangiosis treatment after middle cerebral artery occlusion-induced stroke in mice

There is no effective treatment available for most patients suffering with ischemic stroke, making development of novel therapeutics imperative. The brain's ability to self-heal after ischemic stroke is limited by inadequate blood supply in the impacted area. Encephalomyosynangiosis (EMS) is a neurosurgical procedure that achieves angiogenesis in patients with moyamoya disease. It involves craniotomy with placement of a vascular temporalis muscle graft on the ischemic brain surface. EMS has never been studied in the setting of acute ischemic stroke in mice. The hypothesis driving this study is that EMS enhances cerebral angiogenesis at the cortical surface surrounding the muscle graft. The protocol shown here describes the procedure and provides initial data supporting the feasibility and efficacy of the EMS approach. In this protocol, after 60 min of transient middle cerebral artery occlusion (MCAo), mice were randomized to either MCAo or MCAo + EMS treatment. The EMS was performed 3-4 h after occlusion. The mice were sacrificed 7 or 21 days after MCAo or MCAo + EMS treatment. Temporalis graft viability was measured using nicotinamide adenine dinucleotide reduced-tetrazolium reductase assay. A mouse angiogenesis array quantified angiogenic and neuromodulating protein expression. Immunohistochemistry was used to visualize graft bonding with brain cortex and change in vessel density. The preliminary data here suggest that grafted muscle remained viable 21 days after EMS. Immunostaining showed successful graft implantation and increase in vessel density near the muscle graft, indicating increased angiogenesis. Data show that EMS increases fibroblast growth factor (FGF) and decreases osteopontin levels after stroke. Additionally, EMS after stroke did not increase mortality suggesting that protocol is safe and reliable. This novel procedure is effective and well-tolerated and has the potential to provide information of novel interventions for enhanced angiogenesis after acute ischemic stroke.

A total of 41 mice were used for this study. After three mortalities, one in MCAo and two in MCAo + EMS, a total of 38 mice were used for obtaining the results shown.
Statistics 
Data from each experiment are presented as mean &#177; standard deviation (S.D.). Significance was determined using either unpaired student&#39;s t-test for comparing two groups or one-way ANOVA for more than two groups, with a Newman&#8722;Keuls post-hoc test to correct for multiple comparisons....

Watch this Scientific Journal Video about A Model for Encephalomyosynangiosis Treatment after Middle Cerebral Artery Occlusion-Induced Stroke in Mice at JoVE.com

A Model for Encephalomyosynangiosis Treatment after Middle Cerebral Artery Occlusion-Induced Stroke in Mice

The protocol aims to provide methods for encephalomyosynangiosis-grafting of a vascular temporalis muscle flap on the pial surface of ischemic brain tissue-for the treatment of non-moyamoya acute ischemic stroke. The approach's efficacy in increasing angiogenesis is evaluated using a transient middle cerebral artery occlusion model in mice.

There is no effective treatment available for most patients suffering with ischemic stroke, making development of novel therapeutics imperative. The ...

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Research

JoVE Journal

Neuroscience

2.6K Views.  UConn School of Medicine. The protocol aims to provide methods for encephalomyosynangiosis-grafting of a vascular temporalis muscle flap on the pial surface of ischemic brain tissue-for the treatment of non-moyamoya acute ischemic stroke. The approach's efficacy in increasing angiogenesis is evaluated using a transient middle cerebral artery occlusion model in mice.

Video: A Model for Encephalomyosynangiosis Treatment after Middle Cerebral Artery Occlusion-Induced Stroke in Mice

Focal Cerebral Ischemia Model by Endovascular Suture Occlusion of the Middle Cerebral Artery in the Rat

Stroke is the leading cause of disability and the third leading cause of death in adults worldwide1. In human stroke, there exists a highly variable clinical state; in the development of animal models of focal ischemia, however, achieving reproducibility of experimentally induced infarct volume is essential. The rat is a widely used animal model for stroke due to its relatively low animal husbandry costs and to the similarity of its cranial circulation to that of humans2,3. In humans, the middle cerebral artery (MCA) is most commonly affected in stroke syndromes and multiple methods of MCA occlusion (MCAO) have been described to mimic this clinical syndrome in animal models. Because recanalization commonly occurs following an acute stroke in the human, reperfusion after a period of occlusion has been included in many of these models. In this video, we demonstrate the transient endovascular suture MCAO model in the spontaneously hypertensive rat (SHR). A filament with a silicon tip coating is placed intraluminally at the MCA origin for 60 minutes, followed by reperfusion. Note that the optimal occlusion period may vary in other rat strains, such as Wistar or Sprague-Dawley. Several behavioral indicators of stroke in the rat are shown. Focal ischemia is confirmed using T2-weighted magnetic resonance images and by staining brain sections with 2,3,5-triphenyltetrazolium chloride (TTC) 24 hours after MCAO.

Surgical induction of ischemic brain damage in the rat is a widely used model for stroke research. Here we demonstrate the induction of focal cerebral ischemia by occlusion of the middle cerebral artery. Visualization of the resulting infarct by histological staining and magnetic resonance imaging is also shown.

Stroke is the leading cause of disability and the third leading cause of death in adults worldwide1. In human stroke, there exists a highly variable ...

Lateral Chronic Cranial Window Preparation Enables In Vivo Observation Following Distal Middle Cerebral Artery Occlusion in Mice

Focal cerebral ischemia (i.e., ischemic stroke) may cause major brain injury, leading to a severe loss of neuronal function and consequently to a host of motor and cognitive disabilities. Its high prevalence poses a serious health burden, as stroke is among the principal causes of long-term disability and death worldwide1. Recovery of neuronal function is, in most cases, only partial. So far, treatment options are very limited, in particular due to the narrow time window for thrombolysis2,3. Determining methods to accelerate recovery from stroke remains a prime medical goal; however, this has been hampered by insufficient mechanistic insights into the recovery process. Experimental stroke researchers frequently employ rodent models of focal cerebral ischemia. Beyond the acute phase, stroke research is increasingly focused on the sub-acute and chronic phase following cerebral ischemia. Most stroke researchers apply permanent or transient occlusion of the MCA in mice or rats. In patients, occlusions of the MCA are among the most frequent causes of ischemic stroke4. Besides proximal occlusion of the MCA using the filament model, surgical occlusion of the distal MCA is probably the most frequently used model in experimental stroke research5. Occlusion of a distal (to the branching of the lenticulo-striate arteries) MCA branch typically spares the striatum and primarily affects the neocortex. Vessel occlusion can be permanent or transient. High reproducibility of lesion volume and very low mortality rates with respect to the long-term outcome are the main advantages of this model. Here, we demonstrate how to perform a chronic cranial window (CW) preparation lateral to the sagittal sinus, and afterwards how to surgically induce a distal stroke underneath the window using a craniotomy approach. This approach can be applied for sequential imaging of acute and chronic changes following ischemia via epi-illuminating, confocal laser scanning, and two-photon intravital microscopy.

Lateral Chronic Cranial Window Preparation Enables In Vivo Observation Following Distal Middle Cerebral Artery Occlusion in Mice

Surgical occlusion of a distal middle cerebral artery branch (MCAo) is a frequently used model in experimental stroke research. This manuscript describes the basic technique of permanent MCAo, combined with the insertion of a lateral cranial window, which offers the opportunity for longitudinal intravital microscopy in mice.

Focal cerebral ischemia (i.e., ischemic stroke) may cause major brain injury, leading to a severe loss of neuronal function and consequently to a host of ...

Modeling Stroke in Mice: Transient Middle Cerebral Artery Occlusion via the External Carotid Artery

Stroke is the third most common cause of mortality and the leading cause of acquired adult disability in developed countries. To date, therapeutic options are limited to a small proportion of stroke patients within the first hours after stroke. Novel therapeutic strategies are being extensively investigated, especially to prolong the therapeutic time window. These current investigations include the study of important pathophysiological pathways after stroke, such as post-stroke inflammation, angiogenesis, neuronal plasticity, and regeneration. Over the last decade, there has been increasing concern about the poor reproducibility of experimental results and scientific findings among independent research groups. To overcome the so-called &#8220;replication crisis&#8221;, detailed standardized models for all procedures are urgently needed. As an effort within the &#8220;ImmunoStroke&#8221; research consortium (https://immunostroke.de/), a standardized mouse model of transient middle cerebral artery occlusion (MCAo) is proposed. This model allows the complete restoration of the blood flow upon removal of the filament, simulating the therapeutic or spontaneous clot lysis that occurs in a large proportion of human strokes. The surgical procedure of this &#8220;filament&#8221; stroke model and tools for its functional analysis are demonstrated in the accompanying video.

Different models of middle cerebral artery occlusion (MCAo) are used in experimental stroke research. Here, an experimental stroke model of transient MCAo via the external carotid artery (ECA) is described, which aims to mimic human stroke, in which the cerebrovascular thrombus is removed due to spontaneous clot lysis or therapy.

Stroke is the third most common cause of mortality and the leading cause of acquired adult disability in developed countries. To date, therapeutic options ...

Establishing a Transcranial Middle Cerebral Artery Occlusion Mice Model

A Modified Transcranial Middle Cerebral Artery Occlusion Model to Study Stroke Outcomes in Aged Mice

In experimental stroke research, middle cerebral artery occlusion (MCAO) with an intraluminal filament is widely used to model ischemic stroke in mice. The filament MCAO model typically exhibits a massive cerebral infarction in C57Bl/6 mice that sometimes includes brain tissue in the territory supplied by the posterior cerebral artery, which is largely due to a high incidence of posterior communicating artery atresia. This phenomenon is considered a major contributor to the high mortality rate observed in C57Bl/6 mice during long-term stroke recovery after filament MCAO. Thus, many chronic stroke studies exploit distal MCAO models. However, these models usually produce infarction only in the cortex area, and consequently, the assessment of post-stroke neurologic deficits could be a challenge. This study has established a modified transcranial MCAO model in which the MCA at the trunk is partially occluded either permanently or transiently via a small cranial window. Since the occlusion location is relatively proximal to the origin of the MCA, this model generates brain damage in both the cortex and striatum. Extensive characterization of this model has demonstrated an excellent long-term survival rate, even in aged mice, as well as readily detectable neurologic deficits. Therefore, the MCAO mouse model described here represents a valuable tool for experimental stroke research.

Author Spotlight: Innovative Techniques and Future Directions in Stroke Research 

This protocol demonstrates a unique mouse stroke model with a medium-sized infarct and an excellent survival rate. This model allows preclinical stroke researchers to extend the ischemia duration, use aged mice, and assess long-term functional outcomes.

In experimental stroke research, middle cerebral artery occlusion (MCAO) with an intraluminal filament is widely used to model ischemic stroke in mice. ...

A Model of Transient Cerebral Ischemia by Occlusion of Middle Cerebral Artery

Transient Middle Cerebral Artery Occlusion Model of Stroke

Stroke stands as a major cause of death or chronic disability globally. Nevertheless, existing optimal treatments are limited to reperfusion therapies during the acute phase of ischemic stroke. To gain insights into stroke physiopathology and develop innovative therapeutic approaches, in vivo rodent models of stroke play a fundamental role. The availability of genetically modified animals has particularly propelled the use of mice as experimental stroke models.
In stroke patients, occlusion of the middle cerebral artery (MCA) is a common occurrence. Consequently, the most prevalent experimental model involves intraluminal occlusion of the MCA, a minimally invasive technique that doesn't require craniectomy. This procedure involves inserting a monofilament through the external carotid artery (ECA) and advancing it through the internal carotid artery (ICA) until it reaches the branching point of the MCA. After a 45 min arterial occlusion, the monofilament is removed to allow reperfusion. Throughout the process, cerebral blood flow is monitored to confirm the reduction during occlusion and subsequent recovery upon reperfusion. Neurological and tissue outcomes are evaluated using behavioral tests and magnetic resonance imaging (MRI) studies.

Author Spotlight: Assessing Ischemic Stroke Damage Through Middle Cerebral Artery Occlusion Model 

This protocol describes the model of transient focal cerebral ischemia in mice through intraluminal occlusion of the middle cerebral artery. Additionally, examples of outcome assessment are shown using magnetic resonance imaging and behavioral tests.

Stroke stands as a major cause of death or chronic disability globally. Nevertheless, existing optimal treatments are limited to reperfusion therapies ...

Occlusion of Distal Middle Artery to Develop an Ischemic Stroke Mouse Model

Induction of Acute Ischemic Stroke in Mice Using the Distal Middle Artery Occlusion Technique

Ischemic stroke remains the predominant cause of mortality and functional impairment among the adult populations globally. Only a minority of ischemic stroke patients are eligible to receive intravascular thrombolysis or mechanical thrombectomy therapy within the optimal time window. Among those stroke survivors, around two-thirds suffer neurological dysfunctions over an extended period. Establishing a stable and repeatable experimental ischemic stroke model is extremely significant for further investigating the pathophysiological mechanisms and developing effective therapeutic strategies for ischemic stroke. The middle cerebral artery (MCA) represents the predominant location of ischemic stroke in humans, with the MCA occlusion serving as the frequently employed model of focal cerebral ischemia. In this protocol, we describe the methodology of establishing the distal MCA occlusion (dMCAO) model through transcranial electrocoagulation in C57BL/6 mice. Since the occlusion site is located at the cortical branch of MCA, this model generates a moderate infarcted lesion restricted to the cortex. Neurological behavioral and histopathological characterization have demonstrated visible motor dysfunction, neuron degeneration, and pronounced activation of microglia and astrocytes in this model. Thus, this dMCAO mouse model provides a valuable tool for investigating the ischemiastroke and worth of popularization.

Author Spotlight: Establishing a Reliable Distal MCA Occlusion Model in Mice for Stroke Research

Here, we present a protocol to establish a distal middle cerebral artery occlusion (dMCAO) model through transcranial electrocoagulation in C57BL/6J mice and evaluate the subsequent neurological behavior and histopathological features.

Ischemic stroke remains the predominant cause of mortality and functional impairment among the adult populations globally. Only a minority of ischemic ...

Surgical Procedure for Transient Middle Cerebral Artery Occlusion

Distal Middle Artery Occlusion Procedure to Induce Ischemic Stroke in Mice

Neurological Behavioral Tests in Distal Middle Artery Occluded Mice to Study Ischemic Stroke Outcomes

Periorbital Laser Doppler Flowmetry for MCAO-Induced Ischemic Stroke in Rodents

Periorbital Placement of a Laser Doppler Probe for Cerebral Blood Flow Monitoring Prior to Middle Cerebral Artery Occlusion in Rodent Models

Middle cerebral artery occlusion (MCAO) is the gold-standard method for preclinical modeling of ischemic stroke in rodents. However, successful occlusion is not guaranteed by even the most skilled surgical hands. Errors primarily occur when the filament is not placed at the correct depth and include instances of either no infarction or vessel perforation, which can cause death. Laser Doppler flowmetry (LDF) is a reliable technique that provides real-time feedback on regional cerebral blood flow (CBF) during the MCAO procedure. Here we demonstrate a rapid technique for periorbital placement of a laser Doppler probe for measurement of CBF in both mice and rats. Our rationale was to simplify LDF implementation, encouraging widespread usage for improved surgical reliability. The technique eliminates the need for skull thinning and specialized equipment, with placement at the periorbital region rather than dorsal placement, promoting efficiency and ease of adoption. The protocol described here encompasses presurgical preparations, periorbital Doppler probe placement, and post-operative care. Representative results include visual depictions of procedural elements along with representative LDF tracings illustrating successful MCAO surgeries, with instances of unsuccessful filament placement leading to complications. The protocol illustrates LDF in confirming proper filament placement and offers a simplified procedure compared to alternative methods.

Author Spotlight: Advancing Stroke Research with Periorbital Doppler Monitoring of Regional Cerebral Blood Flow in Rodent Models

A minimally invasive surgical procedure is shown here, which involves placing the laser Doppler probe onto the skull over the distal region of the middle cerebral artery (MCA), a periorbital location suitable for rats and mice, to assess blood flow during transient MCA occlusion.

Middle cerebral artery occlusion (MCAO) is the gold-standard method for preclinical modeling of ischemic stroke in rodents. However, successful occlusion ...