改良兔大脑中动脉阻塞模型的建立

Establishing of model of middle cerebral artery occlusion in rabbits

目的:探讨简单、实用的兔大脑中动脉阻塞(MCAO)模型建立方法。方法:20只新西兰大白兔,随机分 为实验组(16只)和对照组(4只),实验组电凝阻断右侧大脑中动脉,并于术前及术后4h、8h和12h监测动脉血 pO2、pCO2、pH、血糖和体温,对照组仅暴露右侧大脑中动脉而不予电凝。对照组动物在术后4h和12hDWI检查后 处死,实验组在术后1h、4h、8h和12h进行DWI检查后处死,取兔脑组织进行HE染色光镜观察。结果:实验组 术前及术后各时点动脉血pO2、pCO2、pH、血糖和体温差异无统计学意义(P>0.05)。对照组DWI扫描未发现异常, 实验组MCAO后1hDWI右侧基底节和顶叶皮层均显示异常高信号,随时间延长,异常高信号区逐渐增大。实验 组MCAO后1h光镜下未见明显改变,4h光镜下可见神经元细胞核固缩,8h出现间质水肿,12h可见神经细胞坏 死。结论:电凝法制备兔MCAO模型是一种较为理想的方法。

Aim: To establish a simple and practical model of middle cerebral artery occlusion (MCAO) in rabbits. Methods: A total of 20 New Zealand rabbits were randomly assigned into experimental (n=16) and control (n=4) groups. For the experimental group, electrocoagulation was carried out to occlude the middle cerebral artery, whereas the middle cerebral artery of control group was only exposed, but no electrocoagulation was performed. p_ O_2, p_ CO_2, pH, and glucose in the arterial blood and anal temperature of the experimental group at preoperation, 4 h, 8 h, and 12 h after MCAO were detected. After MCAO, the rabbits of the experimental group were examined by diffusion weighted imaging (DWI) at 1 h, 4 h, 8 h, and 12 h. The rabbits of control group were examined by DWI at 4 h and 12 h. Specimens of the brain tissue which were obtained after MRI scanning were observed under microscopy by HE staining. Results: p_ O_2, p_ CO_2, pH,and glucose in the arterial blood and anal temperature of the experimental group had no obvious change after MCAO( P> 0.05). DWI of the control group was normal. After MCAO, the abnormal high signal intensity of DWI was located in the right basal ganglia or cortical areas in the experimental group, and the abnormal high signal intensity area enlarged with time. Light microscopy observing revealed no changes at 1 h, karyopyknosis in neural cells at 4 h, stroma edema at 8 h, and neural cells necrosis at 12 h. Conclusion: MCAO model in rabbits established by the electrocoagulation is an ideal focal cerebral ischemia one.