Effects of insulin-like growth factor-1 on the expression of caspase-3 P20 and Bcl-2 in frontal lobe and hippocampus of dementia model rats

Objective To study the effects of insulin-like growth factor-1(IGF-1) on the expression of caspase-3 P20 and Bcl-2 in frontal lobe and hippocampus of dementia model rats.Methods We established the dementia rat models by transecting bilateral fornix-fimbria and divided them into five groups:normal control group,sham group,dementia group,low dose IGF-1 group and large dose IGF-1group.Dementia model rats received IGF-1(low dose IGF-1 group and large dose IGF-1group) or saline(sham group and dementia group) by cerebroventricully infusion for 21 days after the operation.The normal control group accept no treatment.The expression of caspase-3 P20 and Bcl-2 in frontal lobe and hippocampus of rats in each group were observed,which optical density value(IOD) were determined by immunohistochemistry and image analysis system.Results Compared with the dementia group,caspase-3 P20 intensity of cell positive response in low dose IGF-1 group and large dose IGF-1 group was decreased,student's t-test reveals significant difference in cell IOD value(P0.001).Comparing with large dose IGF-1group,low dose IGF-1 group's Caspase-3 P20 IOD value was decreased obviously,with significant difference(P0.05 or P0.01).Compared with the dementia group,Bcl-2 IOD value of low dose IGF-1 group and large dose IGF-1group was decreased obviously,which was determined by student's t-test revealed significant difference(P0.001).Student's t-test suggested that the Bcl-2 IOD value increased significantly in low dose IGF-1 group compared with large dose IGF-1group.It indicated that Low dose IGF-1 group was better than large dose IGF-1group on the expression of Bcl-2(P0.05 or P0.01).Conclusions The experimental results manifest that IGF-1 can decrease the expression of caspase-3 P20 and increase the expression of Bcl-2 in frontal lobe and hippocampus of rats to depress cell apoptosis in dementia model rats.