Abstract:

Background  Based on the commonly used local cerebral ischemia models, such as clot embolization, photochemically induced thrombosis and sludged blood embolization, a new model of local cerebral ischemia in mice was popularized. Methods The model of distal middle cerebral artery occlusion (dMCAO) was prepared by permanently blocking the distal middle cerebral artery (MCA) of mice. Cerebral blood flow (CBF) was monitored by real-time laser speckle contrast imaging system. Triphenyltetrazolium chloride (TTC) staining and HE staining were used to detect ischemic infarcts. Clark classification was used to evaluate neurological function. Results Laser speckle contrast imaging system showed CBF decreased significantly after ablation of MCA by electrocoagulation. TTC staining showed that the ischemic region was only located in cerebral cortex, and no obvious damage was found in subependymal basal ganglia and hippocampus. HE staining showed that most nerve cells died in the ischemic region, and there was obvious cell density around the ischemic region, which was considered to be inflammatory cells and various nerve cells. One, 3, 7 and 14 d after model preparation, the mice weighed 22, 20.70, 19.50 and 20.10 g, respectively. Body symmetry scores in Clark classification were 0.75, 0.75, 0.50 and 0.50, respectively; gait scores were 0, climbing scores were 0, turning test scores were 0.50, 0.75, 0.50 and 0.25, forearm symmetry scores were 0.25, forced turning scores were 0, beard reactivity scores were 1, 1, 1 and 0.50 respectively. Conclusions The improved new model of dMCAO can simulate local cerebral ischemia with minor neurological defect, and can be used as an experimental model to study the pathophysiological changes and repair process of the vessels after nerve injury as well as the nerve cells involved in the repair
process after nerve injury. 

Key words: Brain ischemia, Middle cerebral artery, Disease models, animal

摘要：

研究背景 在线拴法、光化学法诱导血栓形成、凝血块栓塞法等常用局灶性脑缺血模型的基础上，推广一种新型局灶性脑缺血动物模型。方法 通过永久性阻断小鼠大脑中动脉远端制备大脑中动脉远端闭塞模型，激光散斑血流成像仪实时监测脑血流量，2，3，5-氯化三苯基四氮唑（TTC）染色和HE 染色检测缺血灶，Clark 评分评价神经功能。结果 激光散斑血流成像仪监测显示，电凝灼烧离断大脑中动脉后，脑血流量明显降低。TTC 染色显示，缺血区仅局限于大脑皮质。HE 染色显示，缺血区神经细胞大部分死亡，缺血区周围可见明显的细胞密集，考虑是炎性细胞和各种神经细胞。模型制备后 1、3、7 和 14 d，小鼠平均体重分别为 22、20.70、19.50 和 20.10 g；Clark 评分中身体对称性评分分别为 0.75、0.75、0.50 和 0.50 分，步态评分均为 0 分，攀爬评分均为 0 分，转圈实验评分为 0.50、0.75、0.50 和 0.25 分，前肢对称性评分均为 0.25 分，强迫转圈评分均为 0 分，胡须反应性评分为 1、1、1 和 0.50 分。结论 经优化的新型大脑中动脉远端闭塞小鼠模型可以模拟局灶性脑缺血且神经功能缺损较轻微，可以作为一种实验模型用以研究神经损伤后血管病理生理改变和修复过程以及神经损伤后修复过程中参与的神经细胞及其作用机制。

关键词: 脑缺血, 大脑中动脉, 疾病模型, 动物