Selective and Permanent Occlusion of the Middle Cerebral Artery in Rats: An Experimental Approach for Studying Motor...

With major clinical relevance, ischemic stroke (IS) demands experimental approaches that enable the development of novel adjuvant therapies. Due to the similarity of the cerebral vascular anatomy to humans, rats are widely used as experimental models of IS. However, there remains a need for methods capable of generating an ischemic environment that more closely resembles that observed in humans, employing an approach that prioritizes selective arterial occlusion. In this context, the aim of this study was to establish a reproducible method for performing a craniectomy followed by permanent and selective occlusion of the middle cerebral artery (MCA) in rats, to standardize the model and reduce technical challenges for application in studies of motor and spatial memory deficits. Wistar rats (N = 28) were equally divided into two groups, one undergoing craniectomy alone (SHAM) and the other craniectomy followed by selective MCA occlusion (MCAO). On the seventh and eighth postoperative days, the postural test and the object location recognition memory test were performed, respectively. After euthanasia, brain specimens were collected, and Nissl-stained histological sections were prepared. To demonstrate the feasibility and effectiveness of the method, a detailed surgical protocol was developed, including preoperative preparation, anesthesia, positioning, craniectomy, MCAO, and closure. The applied method demonstrated deficits in the MCAO group, as evidenced by the postural test (p = 0.015) and the object location recognition memory test (p < 0.001). Histological analysis confirmed the selectivity of the approach, with injury involving hippocampal-associated areas such as the perirhinal, entorhinal, and piriform cortices, in addition to the external capsule, while deeper brain structures were preserved. This protocol proved to be a reproducible and effective method for inducing selective MCA ischemia in rats and represents a valid and technically accessible tool for experimental studies investigating pathophysiological and therapeutic mechanisms in ischemic stroke.