Objective To observe the depressive behavior and neuronal damage induced by different doses of corticosterone(CORT)in mice,and to explore the optimal dose for a corticosterone-induced depression model in mice.Methods Forty male C57BL/6J mice were divided randomly into four groups:control group and low,medium,and high CORT groups(20,40,and 60 mg/kg,respectively),treated with the corresponding drug dose by subcutaneous injection for 4 weeks.Behavioral c hanges in mice after corticosterone administration for 3 and 4 weeks were detected by sugar water preference,forced swimming,tail suspension,and open field tests.Morphological changes in neurons in the hippocampal CA1 area and forebrain cortex area were observed by hematoxylin-eosin(HE)and Nissl staining.Serum levels of 5-hydroxytryptamine(5-HT)were detected by enzyme-linked immunosorbent assay.Depression-related behavioral changes induced by different doses of corticosterone were compared.Results The bodyweights of mice in all three CORT groups(20,40,and 60 mg/kg)decreased(P＜0.05)and the preference for sucrose solution decreased(P＜0.01)compared with the findings in the control group.The immobility time in the forced swimming test was prolonged in the CORT 20 and 40 mg/kg groups(P＜0.01)and the immobility time of mice in the tail suspension test was prolonged in the CORT 40 mg/kg group(P＜0.05).The total distance,the length of time spent in the peripheral area was prolonged and the time entering the central area in the open-field experiment were decreased in the CORT 40 and 60 mg/kg groups(P＜0.05),and average speed were decreased in the CORT 40 mg/kg group(P＜0.05).In addition,CORT injection result ed in abnormal neuronal cell morphology,cell deformation,and nuclear condensation in the hippocampal CA1 and forebrain cortex areas,to different degrees.Serum 5-hydroxytryptamine levels were reduced in the CORT 40 and 60 mg/kg groups(P＜0.05).Conclusions CORT 20,40,and 60 mg/kg can induce depression-like behavioral changes and neuronal damage in mice to varying degrees,with the most notable effect at 40 mg/kg.Under experimental conditions,we consider that 40 mg/kg is the best dose for replicating corticosterone-induced depression in model mice.

Objective To observe the depressive behavior and neuronal damage induced by different doses of corticosterone(CORT)in mice,and to explore the optimal dose for a corticosterone-induced depression model in mice.Methods Forty male C57BL/6J mice were divided randomly into four groups:control group and low,medium,and high CORT groups(20,40,and 60 mg/kg,respectively),treated with the corresponding drug dose by subcutaneous injection for 4 weeks.Behavioral c hanges in mice after corticosterone administration for 3 and 4 weeks were detected by sugar water preference,forced swimming,tail suspension,and open field tests.Morphological changes in neurons in the hippocampal CA1 area and forebrain cortex area were observed by hematoxylin-eosin(HE)and Nissl staining.Serum levels of 5-hydroxytryptamine(5-HT)were detected by enzyme-linked immunosorbent assay.Depression-related behavioral changes induced by different doses of corticosterone were compared.Results The bodyweights of mice in all three CORT groups(20,40,and 60 mg/kg)decreased(P＜0.05)and the preference for sucrose solution decreased(P＜0.01)compared with the findings in the control group.The immobility time in the forced swimming test was prolonged in the CORT 20 and 40 mg/kg groups(P＜0.01)and the immobility time of mice in the tail suspension test was prolonged in the CORT 40 mg/kg group(P＜0.05).The total distance,the length of time spent in the peripheral area was prolonged and the time entering the central area in the open-field experiment were decreased in the CORT 40 and 60 mg/kg groups(P＜0.05),and average speed were decreased in the CORT 40 mg/kg group(P＜0.05).In addition,CORT injection result ed in abnormal neuronal cell morphology,cell deformation,and nuclear condensation in the hippocampal CA1 and forebrain cortex areas,to different degrees.Serum 5-hydroxytryptamine levels were reduced in the CORT 40 and 60 mg/kg groups(P＜0.05).Conclusions CORT 20,40,and 60 mg/kg can induce depression-like behavioral changes and neuronal damage in mice to varying degrees,with the most notable effect at 40 mg/kg.Under experimental conditions,we consider that 40 mg/kg is the best dose for replicating corticosterone-induced depression in model mice.