大鼠局灶性脑缺血损伤后半暗带区锌离子的变化

摘要

目的 观察大鼠局灶性脑缺血再灌注后半暗带区锌离子的变化,探讨锌离子在脑缺血再灌注损伤中的可能作用.方法 将28只SD大鼠随机分为假手术组(n=12)和大脑中动脉梗死(MCAO)组(n=16),以线栓法制作大鼠MCAO模型.分别于再灌注0h、3h、12h和24 h时处死大鼠,取脑组织行TTC染色检测梗死体积,并制作脑组织冷冻切片,采用Newport Green(NG)染色法计数半暗带区NG阳性细胞数目并检测其平均荧光强度,分析NG阳性细胞数目与脑梗死体积的相关性.结果 (1)假手术组大鼠脑组织无梗死灶,也未见NG染色阳性细胞.MCAO组大鼠随再灌注时间延长脑梗死体积增大(均P＜0.01),腩缺血半暗带区域NG阳性染色细胞数目随再灌注时间延长递增(均P＜0.01).各时间点间NG染色阳性细胞平均荧光强度无统计学差异(P＞0.05).(2) MCAO组大鼠脑切片NG阳性细胞数目与脑梗死体积比率呈正相关(r=0,88,P＜0.01).结论 锌离子可能参与了脑缺血再灌注损伤的过程.%Objective To investigate the changes of zinc in the penumbra after focal cerebral ischemia-reperfusion injury in rats and to explore the role of zinc during the process of the injury. Methods 28 Sprague Dawley rats were randomly divided into sham group (n=12) and middle-cerebral-artery-occlusion (MCAO) group (n=16). MCAO modle was performed by the suture method. Rats were sacrificed at 0 h, 3 h, 12 h and 24 h after reperfusion. The brains were removed and dyed with 2, 3, 5 triphenyltetrazolium chloride (TTC) to measure the infarct volume. Newport Green was used to detect the chelatable zinc in the penumbra of the brain. Results (1) Neither infarction nor NG positive cells was observed in the brain of sham group rats. The brain infarct volume in MCAO group showed an increasing tendency with the time of reperfusion increasing (P< 0.01). The number of NG positive cells in the penumbra of MCAO group increased within 24 hours after reperfusion (P<0. 01). In MCAO group, the fluorescence intensity of NG positive cells showed no statistical difference among the subgroups with different reperfusion time (P>0. 05). (2) The NG positive cell numbers showed positive correlation with the volume of brain infarction in MACO group (r = 0. 88, P < 0. 01). Conclusions Zinc probably has a direct relationship with the cerebral ischemia reperfusion injury.