大鼠局灶性脑缺血模型的定量分析

Quantitative analysis for evaluating focal brain ischemia in rats

目的 :采用大脑中动脉阻塞 (MCAO)诱导大鼠局灶性脑缺血模型的方法 ,用计算机辅助技术定量分析脑损伤变化及药物保护作用。方法 :以不同 MCAO时间诱导脑缺血并再灌注 2 4 h后 ,观察神经功能缺失症状 ,并以计算机图像分析技术测定脑梗死体积、脑半球面积、皮层及纹状体神经元密度及白蛋白渗出 ;在缺血前后腹腔注射地塞米松 0 .1mg/ kg或尼莫地平 0 .4 mg/ kg,观察药物的保护作用。结果 :缺血 30 min和再灌注 2 4 h可发生神经功能缺失症状、梗死灶形成、缺血侧脑半球面积增加 11.4 %、神经元密度减少 36 .2 %、白蛋白渗出明显增加。地塞米松和尼莫地平可改善神经功能缺失症状 ,显著减小梗死体积 ,抑制缺血侧脑半球面积增加、神经元死亡和白蛋白渗出。结论 :缺血 30 min和再灌注 2 4 h是诱导局灶性脑缺血的合适条件 ,计算机辅助技术客观定量综合评价脑缺血损伤及药物作用是可行的方法。

Objective: To test the methodology for focal rat brain ischemia by middle cerebral artery occlusion (MCAO) and the utility of computer assisted evaluatin of ischemic brain injure. Methods: After MCAO induced focal brain ischemia, the brain was reperfused for 24 h. Neurologic deficiency scores were assesed, and infarct vo lume, brain hemisphere area, neuron density and albumin exudation of cortex and striatum were measured with computer assisted imaging. Dexamethasone (0.1 mg/kg) and nimodipine (0.4 mg/kg) were injected ip 30 min before and 2 h after MCAO to assess their neuroprotective effect. Results:MCAO 30 min and reperfusion 24 h signi ficantly increased neurologic deficiency scores, infarct volumes, brain hemisphere area and albumin exudation, but neuron density was reduced. Both Dexamethasone and nimodipine attenuatd neuronlogic deficits, reduced infarction volume, ischemic hemisphere area, neuron death and albumin exdudation. Conclusion: MCAO and reperfusion of rat brain represents a good model to study focal brain ischemia. The computer assisted imaging is an objective and quantitative technique to evaluate ischemic brain injury and to assess the neuroprotective effect of drugs.