激光多普勒血流仪评价活体大鼠大脑中动脉栓塞模型成功的可行性分析

Evaluation of rat MCAO model by laser Doppler flowmetry

目的:探讨激光多普勒血流仪(LDF)评价活体大鼠脑缺血/再灌注损伤模型制作成功的可行性和可靠性分析。方法:10只体重280-310 g的雄性SD大鼠用传统线栓法制作单侧大脑中动脉阻塞(MCAO)模型,神经功能评分,LDF监测插栓前后大鼠脑血流动态变化。于缺血2 h和再灌注24 h断头取脑,TTC染色检测脑片梗死灶体积。结果:基线血流均值为(224.99±75.00)PU,局灶神经功能障碍评分0分。插栓成功MCAO模型,缺血2 h血流均值为(67.23±6.90)PU,与基线血流差值为157.76PU,降幅约为70%(P<0.01),差异显著。拔拴后血流均值为(216.01±7.30)PU,与缺血2 h血流差值为148.78PU(P<0.01),差异显著;与基线血流差值为-8.98PU(P>0.05),无显著差异。再灌注24 h后,局灶神经功能障碍评分10.35分,脑片TTC染色显示梗死及水肿灶。插栓不成功模型LDF监测显示仍有血流通过,降幅少于基线的50%,再灌注24 h后,局灶神经功能障碍评分0分,TTC染色未见梗死灶。结论:LDF对大鼠脑血流的监测是除神经功能评分以外另一种判断活体大鼠MCAO模型制作成功的可靠而实用的方法。

AIM： To investigate the feasibility and reliability of using laser Doppler flowmetry（LDF） to evaluate the animal model of cerebral ischemia and reperfusion injury in vivo.METHODS： Ten Sprague-Dawley（SD） male rats,weighing 280-310 g,were subject to unilateral middle cerebral artery occlusion（MCAO） with the routine method of line-embolism,and the cortical blood flow was continuously monitored by LDF during ischemia and reperfusion in the rats.Meanwhile,the degree of injury induced by cerebral ischemia and reperfusion was evaluated after MCAO by the nervous scoring of rat criteria.Brain slices were obtained by the method of neck end breaking and brain autopsy at the time point of ischemia for 2 h and reperfusion for 24 h.The volumes of infarction in the brain slices were determined by TTC staining.RESULTS： （1） In the successful MCAO rats,the average local blood flow remarkably decreased from the baseline value of（224.99±75.00）PU to（67.23±6.90）PU in the ischemic period.The mean difference was 157.76 PU and decreasing amplitude of local blood flow was more than 70% by MCAO.In the reperfusion period,the average local blood flow was rapidly recovered to（216.01±7.30）PU after the embolus was pulled out,which was only slightly lower than that of the baseline level without statistical significance.However,the mean difference of 148.78 PU between the local blood flow of reperfusion and local blood flow of cerebral ischemia for 2 h was found（P〈0.01）.The average local nervous score was 10.35 at 24 h after cerebral ischemia and reperfusion,higher than that of the baseline（0 point）.The infracted evidence with remarkable brain edema in the brain slices was clearly observed with TTC staining.（2） In the unsuccessful MCAO rats,the decrease in local blood flow was less than 50%.The local nervous score was 0 point at 24 h,which was equal to the baseline value.No local infraction and brain edema was observed in the brain slices.CONCLUSION： Besides using the local nervous functional scoring,continuously monitoring of blood flow by LDF in vivo is a reliable and useful method to confirm the successful establishment of rat MCAO model.