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 (P0.05). 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

P0.05)

the number of nerve cells and the expression of IGF-1 were increased in hippocampal region of rats (P0.05).     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.