The Experimental Study Of S100β, GFAP And C-fos Expression In Mental Disorder Rats

Objective:To establish a model of chronic unpredictable mild stress(CUMS), and then to observe behavior changes,the expression of S100β,GFAP and c-fos in hippocampus and memory function in depression rats,to explore their mechanism in the development of depression.Methods:Thirty male Wistar rats were divided into control group and stress group.Depression model was established by using chronic unpredictable mild stress stimulation combined with lonely raising for eight weeks.Weight and behavior changes were observed,plasma levels of cortisol were measured by radioimmune assay and S100βprotein concentrations were measured using enzyme linked immuno-absorbent assay.Platform test was used to observe learning and memory function and the expression of S100β,GFAP and c-fos protein in hippocampus were detected by immunohistochemistry.Results:(1)Compared with control group, weight and organic coefficient of brain decreased in model group(P＜0.01),but plasma corticosterone levels increased significantly(P＜0.01).(2)Compared with control group, it was decreased significantly in the crossing and rearing movement times,clean times, the volume of sucrose-intake and the preference of sucrose in model group(P＜0.01).The platform test suggested that the reaction time in model group was prolonged significantly than that of the control,the pre-reaction time was shorten obviously,and the error frequence was increased in model group.(3)The ultrastructure changes in the hippocampus were observed by electron microscope.(4)Plasma concentrations of S100βprotein in model group were higher than that of the control group(P＜0.05),and the expression of S100βand GFAP protein in the hippocampus were increased,but the expression of c-fos decreased.(5)An increase of expression of S100βand GFAP protein were negatively correlated to decline of learning and memory function(P＜0.05).The expression of S100βprotein was positively correlated to GFAP expression(r=0.739, P＜0.01),but the expression of c-fos protein had no correlation to S100βand GFAP. Conclusions:The repeated chronic unpredictable mild stress stimulation can induce long-time changes in acts and activities and damage the hippocampus structure of rats. The chronic mild stimulation can induce an increase of expression of S100βand GFAP and an decrease of c-fos in rat hippocampus.It can also affect learning and memory function of rats,which may play an important role of mental disorder.