银杏叶制剂对脑缺血再灌注后热休克蛋白、c-fos表达的影响

目的： 研究银杏叶制剂对大鼠脑缺血再灌注后热休克蛋白（HSP）、c-fos表达的影响，探讨其神经保护机制。 方法： 采用改良Longa法复制大鼠局灶脑缺血再灌注模型。56只实验大鼠随机分为正常对照组、假手术组、缺血再灌注组及银杏叶制剂预处理组。银杏组大鼠在实验前灌服银杏制剂2 mL，1日3次，连用5 d。应用HSP70及c-fos免疫组化染色、c-fos mRNA原位杂交、原位细胞凋亡及HE染色等方法观察缺血再灌注不同时点（1 h、6 h、12 h、24 h、3 d、7 d）两者的变化，并对其阳性结果进行半定量分析。 结果： 银杏制剂预处理组各时段神经细胞缺血程度明显轻于未处理组、TUNEL阳性细胞数明显少于未处理组，HSP70及c-fos表达的阳性细胞数则明显多于未处理组（P<0.01）。脑缺血再灌注组1 h 时c-fos即有表达，6 h达高峰，后逐渐下降。再灌注6 h组HSP70在缺血侧皮质及基底节开始表达，24 h达高峰。再灌注6 h细胞凋亡最显著。 结论： 银杏制剂可能通过诱导HSP70及c-fos的表达，发挥其神经保护作用。

Effect of Ginkgo biloba extract on the expression of c-fos and HSP70 following focal cerebral ischemic reperfusion in rats

AIM: To investigate the influence of Ginkgo biloba extract (GBE) on the expression of c - fos, heat shock protein 70 (HSP70) during focal cerebral ischemic reperfusion in rats. METHODS: The middle cerebral artery occlusion (MCAO) nwdel described by Zea longa was used. Healthy Wistar rats were randomized to 4 groups. Immunohistochemistry, in situ hybridization and terminal deoxynucleotidyl transferase - mediated dUTP nick end labeling (TUNEL) were used to detect the expression of c - fos gene, HSP70 and cell apoptosis at different reperfusion time points: 1, 6, 12, 24 hours and 3, 7 days after recirculation. RESULTS: The positive reactions of both c - fos and HSP70 were significantly increased at different reperfusion time in GBE - pre-treated ischemia/reperfusion (IR) group than those in ischemia/reperfusion group (P<0.01) and the number of TUNEL - positive cells was reduced in GBE - pretreated IR group. CONCLUSION: The GBE induced the expression of c - fos, HSP70 and contributes to neuroprotective activities after cerebral ischemia.