Influence of chronic corticosterone injection on depression-like behavior and brain glycogen levels in mice / 中国病理生理杂志

ABSTRACT

AIM:To study the effect of chronic corticosterone ( CORT) injection on the depression-like behav-iors and the brain glycogen level in mice.METHODS:Male C57BL/6N mice (n=40) were randomly divided into nor-mal control group and model group.The mice in model group were subcutaneously consecutively injected with CORT for 4 weeks.The mouse model of chronic stress depression was constructed.The forced swim test and open field experiment were conducted to prove chronic stress model.The serum level of CORT in the mice was measured by radioimmunoassay.The protein levels of hippocampal synaptophysin ( SYP) and brain-derived neurotrophic factor ( BDNF) were detected by West-ern blot.Hippocampus glycogen, glycogen synthase and glycogen phosphorylase were determined by indirect fluorescence measurement.RESULTS:Compared with normal control group, the immobility time of the forced swim test in model group was significantly lengthened (P<0.01), and the ability of spontaneous activity was reduced (P<0.01), indicating that chronic CORT injection induced depression-like behaviors in mice.The CORT level increased significantly (P<0.01) in model group.CORT injection decreased the protein expression of hippocampal SYP and BDNF (P<0.01), reduced hipp-ocampal glycogen level (P<0.05) and glycogen synthase activity (P<0.05), and increased glycogen phosphorylase ac-tivity (P<0.05).CONCLUSION:Chronic CORT injection causes hippocampal neuron damage and induces the depres-sion-like behaviors of mice, which may be associated with decreasing hippocampal glycogen level by CORT.