姜黄素对糖尿病脑病大鼠海马IGF-1表达及认知功能影响

目的观察姜黄素对糖尿病脑病大鼠学习记忆、胰岛素样生长因子1(IGF-1)表达的影响,分析姜黄素的脑保护作用机制。方法 40只SD大鼠,随机数字表法选取30只,一次性腹腔注射链脲佐菌素(60 mg/kg)建立糖尿病脑病模型后,随机数字表法分成2组:糖尿病脑病组和姜黄素治疗组;其余大鼠也随机分为2组:正常对照组和正常姜黄素组,建模12周后,姜黄素[60 mg/(kg.d)]持续灌胃12周。第24周时Morris水迷宫观察大鼠认知功能变化,免疫组化、RT-PCR法观察IGF-1表达的变化。结果与正常对照组和正常姜黄素组大鼠相比,糖尿病脑病组大鼠认知功能显著降低;海马区IGF-1表达明显减少(P<0.05)。经姜黄素治疗后,大鼠认知功能得到改善,Morris水迷宫实验的逃避潜伏期,姜黄素治疗组[(34.90±1.81)s]显著短于糖尿病脑病组[(68.70±3.67)s](P<0.01);海马神经细胞数量增多,海马区IGF-1表达增多(P<0.05)。结论大鼠海马IGF-1表达的减少可能在糖尿病脑病发病机制中发挥着重要的作用,姜黄素有脑保护作用,其机制可能是通过调控IGF-1信号通路调节实现的。

Effect of curcumin on expression of IGF-1 in hippocampal nerve cells of rats with diabetic encephalopathy and their cognitive function

Objective To study the effect of curcumin on expression of IGF-1 in rats with diabetic encephalopathy and their memory and its cerebral protective mechanism.Methods A rat diabetic encephalopathy model was established by injecting streptozotocin(60 mg/kg).Thirty rats were randomly divided into diabetic encephalopathy group and curcumin treatment group.Another 10 rats were randomly divided into normal control group and normal curcumin group.Twelve weeks after diabetic encephalopathy model was established,gastric lavage was performed with curcumin [60 mg/(kg·d)] for 12 weeks.Twenty-four weeks later,cognitive function of rats was observed in Morris water maze experiment.Expression of IGF-1 was detected by immunohistochemistry method and RT-PCR,respectively.Results The cognitive function and IGF-1expression levels were significantly lower in diabetic encephalopathy group than in normal control group and normal curcumin group(P<0.05).After treatment with curcumin,the cognitive function of rats was improved,the latent period of escaping from Morris water maze experiment was significantly shorter in curcumin treatment group than in diabetic encephalopathy group(34.90±1.81 s vs 68.70±3.67 s,P<0.05),the number of nerve cells and the expression of IGF-1 were increased in hippocampal region of rats(P<0.05).Conclusion The decreased expression of IGF-1 in hippocampal nerve cells of rats may play an important role in the pathogenesis of diabetic encephalopathy.Curcumin protects brain of rats against diabetic encephalopathy by regulating the IGF-1 signal pathway.