[Establishment and evaluation of reproduction of middle cerebral artery occlusion to produce cerebral ischemia with autologous blood clot and nylon thread in rat]

Abstract

Objective: To reproduce cerebral ischemia using middle cerebral artery, occlusion (MCAO) method with autologous blood clot and nylon thread in rat.

Methods: Rats were randomly divided into sham operation group (n=10), suture occlusion group (n=12), thrombus suture occlusion model group (n=12) in which both autologous blood clot and nylon thread were used (thrombus occluded group). Cerebral ischemia as a result of MCAO in suture occlusion group was replicated by insertion of nylon thread. In thrombus occluded group, a polyethylene catheter containing a nylon thread was inserted into the middle carotid artery via external carotid artery, and the nylon thread was pulled out to an appropriate length to allow blood to coagulate. Fifteen minutes later, thrombin was injected, and the nylon thread was re-inserted to complete MCAO. Specimens were taken after ischemia for 6 hours. Neurological symptoms were observed, brain water ratio and the cerebral infarction size were measured, and the pathological changes in the brain tissue were observed.

Results: Compared with sham operation group, the evaluation score of neurological symptoms was significantly higher, and water content and cerebral infarction size were larger in suture occlusion group and thrombus occluded group (all P<0.01); the pathological changes of the brain were also more marked. Compared with suture occlusion group, thrombus occlusion group showed no differences in evaluation score, water content, cerebral infarction size and pathological changes of the brain (all >0.05).

Conclusion: In rats, occlusion of middle cerebral artery with autologous blood clot and inserted nylon thread can result in the functional lesion, edema and the pathological changes in the brain. The MCAO reproduced by this method could produce thrombotic obstruction of the middle cerebral artery for the experimental study of cerebral ischemic/reperfusion injury, and it could prevent hemorrhage in the process of replication of animal model and in the course of thrombolysis therapy in the clinic. The model has the advantages of precision of the occlusion site, production of constant cerebral infarction size, easier performance and good repeatability.