Effect Of Ketamine On Behavior Of Chronic Unpredictable Mild Stress Mice

Background:Depression is a persistent situational disorder that is characterized by markedly low context.According to statistics,there are currently about 350 million patients worldwide.Studies have found that a single sub-anaesthetic doses of ketamine administration intraperitoneally has antidepressant effects,with the characteristics of fast onset and long duration(about 2 weeks).To investigate the effect of ketamine on the depressive behavior of depression mice with chronic unpredictable mild stress has a positive significance in the study of its antidepressant mechanism.Methods:Mice were randomly divided into three groups:normal group,depression group,and ketamine group(10 mg/kg).The mouse model of depression was established by chronic unpredictable mild stress.The normal group was raised according to the normal mouse feeding conditions.The mice in the depression group and the ketamine group were treated with chronic unpredictable mild stress to establish a mouse model of depression.After finishing the chronic unpredictable mild stress,10 mg/kg of ketamine(ketamine group)or the same dose of normal saline(normal group and depression group)were injected intraperitoneally.The behavior of mice in the open field test,sucrose preference test,tail suspension test and forced swimming test was determined 24 h after administration.RESULTS:The body weight of mice receiving chronic unpredictable mild stress was significantly lower than that of the normal group(P<0.05).The crossing score of the open field test in the depression group was significantly lower than that of the normal group,and it could be reversed by abdominal administration of ketamine(10 mg/kg).There was no significant difference in the rearing score in the open field test between the normal group(P=0.296)and the ketamine group(P=0.091)compared with the depression group.The time of immobility in the open field test of the depression group was significantly higher than that of the normal group(P<0.01),and it could also be reversed by a single intraperitoneal administration of ketamine at a sub-anaesthetic dose(P<0.01).The immobility time of the forced swimming test in the depression group was obviously higher than that of the normal group(P<0.05)and the ketamine group(P<0.05).The immobility time in the tail suspension test of the depression group was greatly longer than that of the normal group,and it could be reversed by intraperitoneal injection of ketamine(P<0.05,P<0.05).Compared with the normal group,the sucrose consumption percentage of the mice in the depression group was significantly reduced(P<0.05)and could be reversed by ketamine(P<0.05).CONCLUSION:Chronic unpredictable mild stress can significantly reduce the crossing scores in the open field test and the percentage of sucrose consumption in the sucrose preference test,decrease the crossing score in the open field test,and the immobility time in the forced swimming test and tail suspension test Ketamine can reverse these depressive behavior changes and function as antidepressants.