糖皮质激素对糖尿病大鼠学习记忆及Bax表达的影响

The effect of glucocorticoid on learning and memory ability and the expression of Bax in hippocampi of diabetic SD rats

目的探讨糖皮质激素对糖尿病大鼠学习记忆及Bax表达的影响。方法 SD大鼠腹腔注射链脲佐菌素诱导糖尿病大鼠模型,将实验分为3组:正常对照组,糖尿病组,RU486组(糖皮质激素受体阻断剂)即给予RU486的糖尿病大鼠。3个月后水迷宫检测大鼠学习记忆能力,TUNEL染色检测脑海马区神经元凋亡,免疫组化及Western检测脑海马区Bax蛋白表达。结果水迷宫检测显示,与对照组相比糖尿病大鼠逃避潜伏期延长,穿越平台次数减少(均<0.01),出现了学习记忆能力减退的表现,RU486组较对照组无明显变化(>0.05)。与对照组相比,糖尿病组脑海马区凋亡神经元数目增多,Bax表达增加(<0.01),RU486组较对照组无明显变化(>0.05)。结论糖皮质激素能促进糖尿病大鼠脑海马区凋亡相关基因Bax表达,诱导神经元凋亡,损害学习记忆能力。

Objective To explore the effect of glucocorticoid on learning and memory ability and the expression of Bax in hippocampi of diabetic SD rats. Methods SD rats were assigned into 3 groups： control group, diabetic group（intraperitoneal injection of streptozotocin） and RU486（glucocorticoid receptor antagonist） group. Three month later, learning and memory ability was revealed by water maze, apoptosis of hippocampal neurons was detected by TUNEL staining, and the expression of Bax in hippocampi was explored by immunohistochemistry and Western blot. Results The escape latency increased and cross number decreased in diabetic group than in control group（P〈 0.01）, but with no difference between RU486 group and control group（P〉0.05）. The number of apoptotic neurons and the expression level of Bax in hippocampi were increased in diabetic group than in control group（P〈0.01）, but with no difference between RU486 group and control group（P〉0.05）. Conclusion The damage of glucocorticoid on the learning and memory ability of diabetic rats might be related to the induction of apoptotic neurons and upregulation of bax expression in hippocampi.