Effects of estrogen on learning and memory function and the expressions of IGF-1 in CA_1 region of hippocampus in vascular dementia rats

Objective To explore the effects of estrogen on learning and memory function and the expressions of IGF-1 in CA1 region of hippocampus in vascular dementia(VD)rats.Methods 30 healthy male Sprangue-Dawley rats were divided into three groups by random:sham-operated group,model group and estrogen group,with 10 rats in each group.VD models were made with permanent bilateral common carotid arteries occlusion.The 17-β estradiol(1mg/kg,dissolution in peanut oil)was intraperitoneally injected in estrogen group,once in other day,for 30 times.While,same-dose peanut oil was intraperitoneally injected in the sham-operated group and model group once in other day,totally 30 times.After 60d the capability of learning and memory were observed by Morris Water Maze test.Neuroal morphology and the expression of IGF-1 in hippocampal CA1 subregion were detected by HE and immunohistochemistry stain respectively.Results No ischemic changes were found in CA1 region of hippocampus in sham-operated group.Cell count of CA1 in hippocampus was significantly decreased in model group.Most of neurons kept stuctures and shapes in estrogen group.Compared to sham-operated group,cognitive ability in the model group and estrogen group was significantly decreased;the expressions of IGF-1 was increased in CA1 region of hippocampus(all P0.05).Compared to model group,the cognitive disorder significantly alleviated;the expression of IGF-1 markedly increased(all P0.05).Conclusion 17-β estradiol in the VD rat brain damage and cognitive function has improved significantly,and this may increase IGF-1 in hippocampus of content.