姜黄素对糖尿病脑病大鼠海马IGF-1/IGF-1R表达的影响

Impact of curcumin on the expression of IGF-1/IGF-1R in hippocampal neuron of diabetic encephalopathy rats

目的观察姜黄素对糖尿病脑病大鼠胰岛素样生长因子1(IGF-1)、胰岛素样生长因子受体(IGF-1R)表达的影响,分析姜黄素的脑保护作用机制。方法实验动物分为4组:正常对照组(A组)、正常姜黄素组(B组)、糖尿病脑病组(C组)和姜黄素治疗组(D组)。以大鼠一次性腹腔注射链脲佐菌素(STZ)建立糖尿病脑病模型,姜黄素持续灌胃12周。观察大鼠的体质量、血糖、糖化血红蛋白变化,采用免疫组化、RT-PCR法检测IGF-1及IGF-1R表达的变化。结果与A组和B组大鼠相比,C组大鼠血糖、糖化血红蛋白明显增高,体质量下降,海马区IGF-1表达明显减少(P<0.05),同样海马神经元IGF-1R表达减少(P<0.05)。经姜黄素治疗后,D组大鼠糖化血红蛋白下降,体质量增加,血糖变化不大,海马神经元IGF-1表达增多(P<0.05),随之海马神经元IGF-1R表达增多(P<0.05)。结论大鼠海马IGF-1/IGF-1R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。

We aimed to study the impact of curcumin on IGF-1/IGF-1R tentatively and the protective mechanism against diabetic encephalopathy.Rats were randomly divided into 4 groups： normal controls（group A）,curcumin-treated normal controls（group B）,untreated models（group C）,and curcumin-treated models（group D）.Rat received a single dose of Streptozotocin（STZ） to make the experimental model of diabetic encephalopathy,followed by supplementation with curcumin for 12 weeks.The rats were examined for weight,blood glucose,HbA1c and then sacrificed for RT-PCR and immunohistochemical staining assays.Compared with groups A and B,blood glucose,HbA1c in group C significantly increased,but weight decreased.Furthermore,the content of IGF-1/IGF-1R in the hippocampal of group C decreased obviously.After the curcumin treatment,the model rats demonstrated depressed glycosylated hemoglobin level,unchanged blood glucose level,as well as increased weight and IGF-1/IGF-1R expression.We presume that the decreased expression of IGF-1/IGF-1R in hippocampal neurons of the model rats might play an important role in the pathogenesis of diabetic encephalopathy.Thus,the prevention of curcumin from diabetic encephalopathy possibly works through regulating the expression level of IGF-1 in hippocampal neurons of the model rats.