大鼠全脑缺血再灌注脑内神经营养因子的动态变化

Dynamic changes of neurotrophic factors in different cerebral areas after full cerebral ischemia and reperfusion in old rats

目的 探讨血管性痴呆与神经生长因子 (NGF)、脑源性神经营养因子 (BDNF)之间的关系。方法 选用Wistar老龄大鼠雌雄随机分组 ,假手术组分A、B、C 3组 ,每组 4只 ;实验组分全脑缺血 15分钟组 ,缺血再灌注 1和 6小时、2、4、9天 5组 ,每组 5只。术前、术后测试游水谜成绩 ,用免疫组化ABC法检测缺血再灌注不同时相额叶、顶叶、海马和丘脑NGF、BDNF含量。结果 额叶NGF表达于再灌注 2天达高峰 ,以后迅速消失 ;缺血 15分钟顶叶即出现中量NGF表达 ,再灌注 9天时增至大量 ;缺血再灌注早期丘脑NGF表达消失 ,再灌注 2天以后NGF表达重新出现。再灌注 2天额叶BDNF表达大量增加 ,以后减少、消失 ;顶叶和海马BDNF表达始终无变化 ;丘脑BDNF表达只有再灌注 9天增加。结论 BDNF比NGF分布广泛 ,缺血再灌注早期额叶有NGF、BDNF较好的神经元保护机制 ;顶叶、海马对缺血再灌注损伤有NGF、BDNF迅速、持久的神经元保护机制 ;丘脑缺乏NGF良好的神经元保护机制 ,但有BDNF良好的神经元保护作用。

Objective To explore the relationship between vascular dementia and nerve growth factor (NGF)and brain derived neurotrophic factor (BDNF). Methods 42 male and female senile Wistar rats were randomized into control and experimental groups. The control group was subdivided into A, and C three groups and the experimental group into 6 subgroups, i.e 15 min of ischemia alone and ischemia combined with reperfusion of 1 h, 6 h, 2d, 4d and 9d. Swimming maze was performed before and after operation. The contents of NGF and BDNF in different parts of brain were examined in different periods of ischemia and reperfusion with ABC method of immunocytochemistry. Results NGF expression in frontal lobes reached a peak level in 2 days after reperfusion and then disappeared quickly, that in parietal lobes showed a moderate level in 15 minutes of ischemia and reached a peak in 9 days of reperfusion. However, there is no expression in thalamus in early ischemia and reperfusion, but reexpression occurred after 2 days of reperfusion. BDNF expression showed a peak level after 2 days of reperfusion and then decreased in frontal lobes, but a high level of expression that was unchanged in parietal lobes and hippocampal areas. The increasing expression in thalamus occurred only 9 days after reperfusion. Conclusion The distribution of BDNF was wider than that of NGF. There was a good protective action of NGF and BDNF in frontal lobes in the early period of ischemia with reperfusion and there existed persistent and prompt action of the neurotrophic factors in pariental lobes and hippocampal areas. The protective action of NGF in thalamus was poor , but that of BDNF was good.