大鼠大脑中动脉阻塞再灌注模型改良的实验研究

目的通过对大鼠大脑中动脉阻塞(middle cerebral artery occlusion,MCAO)再灌注模型神经功能缺失评分的计算和脑梗死体积的测量,评价改良的大鼠MCAO再灌注模型,为实验研究提供可重复性好、稳定可靠的动物模型。方法20只SD大鼠随机分为A、B两组,A组用头端烧制成圆球的传统"圆头线栓",B组采用头端用万能胶包裹成梭形膨大的改良"梭头线栓"制作大鼠MCAO模型,阻断大脑中动脉血供3h后将"线栓"拔出,造成再灌注损伤。采用"盲法"分别于再灌注10min和再灌注24h对大鼠进行神经功能缺失评分;再灌注24h后处死大鼠,脑切片TTC染色,数码相机照相,采用图像分析系统测量脑梗死体积比;根据统计结果评价改良的MCAO再灌注模型,分析MCAO再灌注后神经功能缺失评分与脑梗死体积比之间的关系。结果B组大鼠脑梗死体积比大于A组(P<0.01);B组大鼠脑梗死体积比明显较A组稳定,变异系数(coefficient of variation,CV)分别为CVB=0.12,CVA=1.08);再灌注10min和再灌注24h对大鼠进行神经功能缺失评分,B组评分均高于A组(P<0.05);MCAO再灌注模型大鼠神经功能缺失评分与脑梗死体积比的大小成线性相关关系(r=0.873,P<0.01)。结论采用改良的"梭头线栓"制作MCAO再灌注模型,神经功能缺失评分和脑梗死体积比变异度小、稳定性高,是可靠的制模方法;神经功能缺失评分能反映脑梗死的严重程度,可用作评价药物疗效的指标。

An Experimental Study on the Improved Model of Middle Cerebral Artery Occlusion Reperfusion

Objective To evaluate the modified method of suture-embolus by which to establish the model of the middle cerebral artery occlusion(MCAO)and reperfusion in rats on the evaluation of neurobehavioral function and on the volume ratios of brain infarction.Methods Sprague-dawley(SD) rats were marked by group A or B;there were 10 rats in every group.The rats of group A subjected to temporary MCAO with heated round tip suture-embolus;the rats of group B subjected to temporary MCAO with glue-coated shuttled tip suture-embolus.After occlusion for 3 h,the sutures were removed and the brains of rats were reperfused.The neurobehavioral function of rats were evaluated by a person who had known nothing about the group of the rats at 10minutes and 24 h after reperfusion.Then the rats were killed.The brains of the rats were removed and stained with 2,3,5-triphenyltetrazolium chloride(TTC),Calculated the infarct volume ratios through the results of TTC by the system of the image analyses.The results were compared between two groups.Results The infarct volumes ratios were significantly higher in rats of group B than those of the group A(P<0.01).The infarct volume ratios of the rats of group A was tended to be significantly smaller and more inconsistent than those of group B(coefficient of variation(CV)of the group A is 1.08,CV of the group B is 0.12).There was a significantly liner correlation between the neurobehavioral function and the volume of brain infarction(r=0.873,P<0.01).Conclusion Establishment of the model of MCAO reperfusion using the glue-coated shuttled tip suture-embolus is proved to be a reliable and effective method.The evaluation on the neurobehavioral function can reflex well in the volume of brain infarction.