The Effection Of Pregnenolone On Cholinergic System Activity And Synapsin 1 Protein Expression Of Aged Rats

Objective To inquire the effect of pregnenolone on cholinergic system activity and synapsin 1 expression in the hippocampal, temporal,prefrontal areas of brain in aged SD rats.Methods Forty 24-month-old male SD rats were randomly divided into four groups. The following drug treatments were applied for one month:normal control group, solvent control group (intraperitoneal injection with DMSO of equal volume once every other day), low-dose group (intraperitoneal injection with PREG according to the proportion of 0.5mg/kg once every other day), and high-dose group (intraperitoneal injection with PREG according to the proportion of 2.0mg/Kg once every other day). Animals were sacrificed one month after the drug treatment. Brains were quickly removed, hippocampus, temporal and frontal cortex cut out, immediately frozen and stored at-80 oC.The protein expression of choline acetyltransferase (ChAT) and synapsin 1(SYP1) were analyzed by means of Immunohistochemistry (IHC) and Western blot methods,activity of ChAT,acetylcholinesterase(AchE) and serum pregnenolone (PREG) concentrations were measured by means of ELISA detection kit. Then image analysis software and stata system were used to measure the experimental results.Results High dose PREG increased significantly the expression of ChAT, SYP1, PREG of aged rats, and reduced the expression of AchE (P＜0.05), while low dose PREG only increased the consent of PREG of plasma.Conclusions High dose PREG can increase the expression of SYP1 and cholinergic system activity of aged rats,which may be able to improve memory function.