银杏叶提取物对慢性脑低灌注大鼠认知功能的影响

目的观察银杏叶提取物(EGB)对慢性脑低灌注大鼠认知功能的影响,及对海马CA1区脑源性神经营养因子(BDNF)和N-甲基-D-门冬氨酸受体-2B(NMDAR-2B)表达的调节作用,探讨EGB保护认知功能的可能机制。方法将34只Wistar大鼠随机分为正常对照组(6只)、模型组(6只)、EGB高剂量组(8只)、EGB低剂量组(8只)和石杉碱甲组(6只)。采用Morris水迷宫系统检测各组大鼠学习记忆能力,采用免疫组织化学法观察大鼠海马CA1区BDNF和NMDAR-2B的表达。结果永久性结扎双侧颈总动脉术后第1个月时,各组大鼠学习记忆能力比较,差异无统计学意义(P0.05);术后第2个月时,与模型组比较,其他4组学习记忆能力明显下降,差异有统计学意义(P0.01),海马CA1区BDNF和NMDAR-2B表达明显增高,差异有统计学意义(P0.05)。结论海马CA1区BDNF和NMDAR-2B表达降低可能是大鼠认知功能障碍的诱因之一。EGB和石杉碱甲在改善慢性脑低灌注大鼠认知功能障碍方面具有同等效应。

The Effects of EGB on cognitive function in rats with chronic cerebral hypoperfusion

Objective To observe the effects of extract of Gingko biloba leaf(EGB) on cognitive function and the expression of BDNF and NMDAR-2B in hippocampal CA1 area of rats with chronic cerebral hypoperfusion,and to study the mechanism of action of EGB on cognitive function. Methods Wistar rats were randomly divided into five groups:normal control group,model group,EGB high dose group,EGB low dose group,huperzine A tablet control group.The chronic cerebral hypoperfusion model was established by permanent occlusion of bilateral common carotid arteries(2VO).The capability of learning and memory of rats were examined with Morris water maze.Immunohistochemistry was adopted to detect the expression of BDNF and NMDAR-2B in hippocampus.Results In the 2nd month after 2VO,compared with other four groups,the capability of learning and memory of rats was obviously decreased in model group (P < 0.01),and the expression of both BDNF and NMDAR-2B was decreased in hippocampal CA1 area of rats in model group (P <0.05).Conclusion Chronic cerebral hypoperfusion caused cognitive dysfunction of rats,and the decrease of the expression of both NMDAR-2B and BDNF in hippocampal CA1 area of rats may be one of the causes of cognitive dysfunction of rats.EGB could improve cognitive function and enhance the expression of both BDNF and NMDAR-2B in hippocampal CA1 area of rats with chronic cerebral hypoperfusion.