银杏叶提取物对糖尿病性脑病大鼠的保护作用

Protective Effect of Ginkgo Biloba Extract on Rats with Diabetic Encephalopathy

目的:研究糖尿病性脑病与海马区神经元型一氧化氮合酶(nNOS)表达及一氧化氮(NO)、丙二醛(MDA)含量的关系及应用银杏叶提取物(EGb)治疗的效果和机制。方法:雄性Wistar大鼠30只随机分为3组各10只,A组为正常对照大鼠,B、C组按链脲佐菌素(STZ)制成糖尿病大鼠模型,C组应用EGb治疗。1个月后水迷宫试验观察3组大鼠行为学改变,免疫组化检测海马nNOS表达,脑组织匀浆检测NO、MDA水平。结果:①水迷宫试验,B组大鼠出现学习、记忆功能障碍,C组则明显减轻(P<0.01)。②nNOS表达,A组无显示,B组海马区呈强阳性表达,C组表达低于B组(P<0.01)。③NO、MDA水平,B组均明显升高,C组显著低于B组(P<0.01)。结论:海马区nNOS表达升高是糖尿病性脑病发生的重要因素,EGb可下调nNOS表达,对糖尿病性脑病有较好的治疗作用。

Objective： To study the relationship between diabetic encephalopathy and hippocampal nNOS expression, NO and MDA contents, and investigate the effect and therapeutic mechanism of Ginkgo biloba extract （Egb） on diabetic encephalopathy. Methods： STZ were used to make the model of diabetes mellitus, and in EGb injected group EGb was intraperitoneally injected every day. The behavioral abnormalities were investigated by water maze test, and the NO and MDA contents in brain tissue homogenate determined. Immunohistochemistry method was performed to detect the positive expression of nNOS. Results： （1） By maze water test dysfunction of learning and memory was detected in diabetic encephalopathy group, and the matters were improved in EGbP〈treatment group. （2） No expression of nNOS was detectable in control group. In the diabetic encephalopathy group the expression of nNOS was positive in hippocampus, and the expression was weaker in EGb-treatment group. （3） Compared with control group, the NO and MDA contents in brain homogenate were increased in the diabetic encephalopathy group. In the EGb-treatment group the levels were dramatically reduced. Conclusion： Diabetic encephalopathy may be closdy related to hippocampal nNOS expression. EGb has an effect on diabetic encephalopathy and the mechanism of brain protection may be attributed to its effect by down-regulating the nNOS expression.