异丙酚对大鼠脑缺血/再灌注时脑组织c-fos基因表达的影响

Effect of propofol on the expression of c-fos protein and c-fos mRNA in hippocampus during global cerebral ischimia-reperfusion in rats

目的 观察异丙酚在大鼠脑缺血/再灌注时对脑组织c-fos蛋白及c-fos mRNA表达的影响,从蛋白和分子水平探讨异丙酚脑保护作用的机制。方法 采用Pulsinelli-Brierley四血管闭塞的方法制作急性全脑缺血/再灌注损伤模型。40只大鼠随机分为假手术组、缺血/再灌注对照组和缺血/再灌注异丙酚处理组,后者根据异丙酚剂量又分为C1(50 mg·kg-1)、C2(100 mg·kg-1)和C3(150 mg·kg-1)三个亚组。全脑缺血10 min再灌注60 min时处死大鼠,分别采用免疫组织化学方法和半定量逆转录聚合酶链反应(RT-PCR)技术,对缺血/再灌注后脑内c-fos蛋白及c-fos mRNA在海马组织的表达进行检测。结果 缺血/再灌注后皮层、海马、纹状体及边缘区等脑区均有大量的c-fos阳性蛋白表达,其中对照组呈强阳性表达,假手术组仅有少量c-fos阳性蛋白表达,异丙酚处理组则能明显抑制各脑区c-fos蛋白的表达,尤以海马CA1区最为显著;半定量RT-PCR结果显示,缺血,再灌注后海马组织c-fosmRNA表达较假手术组显著增高,而异丙酚处理组则可明显抑制缺血,再灌注后海马组织c-fos mRNA的异常表达。结论 异丙酚的脑保护作用可能与下调c-fos基因表达有关。

Objective To investigate the effect of propofol on the expression of c-fos protein and c-fos mRNA in hippocampus during global cerebral ischemia-reperfusion in rats. Methods Forty male Wistar rats weighing 250-320 g were randomly allocated to one of five groups: group A received sham operation ( n = 8); group B received ischemia-reperfusion (I-R n = 8); group C received intraperitoneal propofol 50 mg·kg-1(C1 n = 8) or 100 mg@kg-1(C2 n = 8) or 150 mg2kg-1(C3 n = 8) 10 min before I-R. The animals were anesthetized with intraperitoneal pentobarbital 40 mg·kg-1.Vertebral arteries were surgically exposed and permanently occluded by coagulation. Bilateral common carotid arteries were exposed. 4-0 silk suture was placed around the arteries. Global cerebral ischemia was induced by lighting the suture for 10 min which was then loosened for reperfusion. At the end of 60 min reperfusion the animals were decapitated on ice and brain was immediately removed. Different brain tissues were either kept in liquid nitrogen ( - 80℃) or fixed in 10% formalin. The changes in c-fos protein in brain was evaluated by immuno-histochemical methods and c-fos mRNA expression in hippocampus was detected using semiquantitative RT-PCR technique.Results The c-fos expression was minimal in sham operation group. I-R induced significant increase in the expression of c-fos protein and c-fos mRNA and propofol significantly inhibited the increase in c-fos expression induced by I-R. The levels of c-fos expression were higher in group C1 than that in group C2 (P < 0.05), but there was no significant difference in the levels of c-fos expression between group C2 and C3 (P > 0.05) . Conclusion The study shows that propofol can significantly inhibit expression of c-fos protein and c-fos mRNA induced by global cerebral I-R.