Published: May 5th, 2023
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. 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.
Nearly 800,000 people suffer a stroke in the US every year, and most of these strokes are ischemic in nature1. Timely restoration of the cerebral blood flow with tissue plasminogen activator (tPA) and/or thrombectomy is currently the most effective treatment for stroke patients; however, the full recovery of neurologic functions in the long term is rare2,3. Thus, searching for novel stroke therapy that targets functional improvement is an intense area of research that requires clinically relevant animal models of stroke.
The most common ischemic stroke mode....
All procedures described in this work are conducted in accordance with the NIH guidelines for the care and use of animals in research, and the protocol was approved by the Duke Institute Animal Care and Use Committee (IACUC). Young (8-10 weeks old) and aged (22 months old) male C57Bl/6 mice were used for the present study. An overview of this protocol is illustrated in Figure 1.
1. Surgical preparation
With a direct view under a surgical microscope, it can be visually confirmed that MCA blood flow is blocked during ischemia. Our previous study showed a >80% blood flow reduction in the ischemic area using a laser Doppler monitor6. In order to determine post-MCAO blood flow changes, LSCI can be used to further confirm the ischemic insult and reperfusion (Figure 1). Indeed, in Figure 3A, it is observed that the blood supply was reduced.......
The first transcranial MCA occlusion model was established in rats in 198111,12, and replaced by the no-craniectomy MCAO model in 19894. The initial transcranial MCA occlusion had a wide surgical field, such that the entire zygomatic arch was removed and the muscles pulled laterally. Local tissues were swollen after surgery, causing stress and decreased food intake for the animals. In our modified transcranial MCAO model, the incision is l.......
The authors thank Kathy Gage for her editorial support. Scheme figures were created with BioRender.com. This study was supported by funds from the Department of Anesthesiology (Duke University Medical Center) and NIH grants (NS099590, HL157354, NS117973, and NS127163).....
|0.9% sodium chloride
|2,3,5-Triphenyltetrazolium Chloride (TTC)
|Sigma or any available vendor
|20 G IV catheter
|20 GA 1.6 IN
|30 G needle
|4-0 silk suture
|Black braided silk
|8-0 suture with needle
|Anesthesia induction box
|Any suitable vendor
|High temperature cautery loop tip
|Laser doppler perfusion monitor
|Lubricant eye ointment
|Bausch + Lomb
|Mouse rectal probe
|2.5 mm Speculum
|Injectable 50 mg/mL
|Triple antibioric & pain relief
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