目的 观察大鼠局灶性脑缺血再灌注后缺血半暗带神经元蛋白表达和凋亡的动态变化.方法 48只雄性Wistar大鼠随机分为假手术组8只和模型组40只,模型组又根据缺血再灌注时间分为6、24、48 h和3、5d5个时间点,各时间点8只.免疫组织化学法观察各组大鼠脑缺血半暗带神经元Bcl-2及Bax蛋白表达,TUNEL法观察相应区域神经元凋亡的动态变化.结果 与假手术组比较,模型组大鼠缺血再灌注6 h Bcl-2、Bax阳性细胞明显增加,随时间延长,Bcl-2阳性细胞逐渐下降,48 h最低；而Bax阳性细胞则逐渐增加,于48 h达到高峰;Bcl-2/Bax比值变化趋势与Bcl-2阳性细胞相一致；各时间点均可见神经元凋亡,48 h达高峰(P＜0.01).相关分析显示,神经元凋亡与Bax蛋白表达呈正相关(r＝0.352,P＜0.05),与Bcl-2和Bcl-2/Bax比值呈负相关(r＝-0.517,r＝-0.529,P＜0.01).结论 大鼠脑缺血半暗带存在大量神经元凋亡,其机制可能与Bcl-2/Bax比值失衡有关.%Objective To observe the dynamic changes of neuronal protein expression and apoptosis in rats with cerebral ischemic penumbra after focal ischemia/reperfusion(I/R). Methods Forty-eight male Wistar rats were randomly divided into sham operation group(n = 8) and model group (n = 40). The model group was further divided into 6,24,48 h,3 d and 5 d I/R groups(8 in each group). Bcl-2 and Bax protein expressions were detected in ischemic penumbra of different groups by immunohistochemistry, and dynamic changes of neuronal apoptosis in corresponding regions were detected with TUNEL staining. Results The number of Bcl-2 and Bax positive cells was significantly greater in model group than in sham operation group 6 h after I/R. The number of Bcl-2 positive cells decreased gradually with the porlongatinn of time and reached its minimium 48 h after I/R, while that of Bax positive cells increased gradually and reached its peak 48 h after I/ R. The ratio of Bcl-2/Bax was consistent with the number of Bcl-2 positive cells. Neuronal apoptosis occurred at different time points and reached its peak 48 h after I/R(P<0. 01). Correlation a-nalysis showed that the neuronal apoptosis was positively related with the expression of Bax protein (r = 0. 352,P<0. 05) and negatively related with the expression of Bcl-2 protein and the ratio of Bci-2/Bax(r= —0. 517 ,r= —0. 529 ,P<0. 01). Conclusion Neuronal apoptosis occurs in rats with cerebral ischemic penumbra,which may be related with the imbalanced ratio of Bcl-2/Bax.
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