Apelin-13 Ameliorates The Depressive Like Behavior And Neuroinflammation Induced By Stress Co-treated With LPS

[background and objective] depression is a worldwide problem,mainly for anhedonia,cognitive and memory deficits,high suicide rate and other characteristics,explore pathogenesis of depression and find new drug treatment is significant.Clinical study found that patients with depression of astrocytes and microglia was activated,the expression of inflammation the factor was significantly increased,suggesting that neuroinflammation may be an important pathogen of depression.Apelin is a new adipocytokine,first isolated from bovine stomach extract.The Endogenous receptor of apelin is a member of G protein coupled receptor family,which is abundantly distributed in the central nervous system,has antidepressant,neuroprotective effect.however,whether the antidepressant effect of Apelin-13 is due to its effect on neuroinflammation is still unknown.This study explores the potential functions of Apelin-13 on depression induced by stress co-treated with LPS.[method] In this study,the sucrose preference test,forced swimming test and body weight increment were used to measure depressive behavior induced by stress co-treated with LPS.The effects of apelin-13 on glucocorticoid secretion induced by stress co-treated with LPS were studied by adrenal weight ratio.The effects of apelin-13 on the activation of microglia and astrocytes were studied by the expression level of IBA-1 and GFAP through western blot.The effects of apelin-13 on the activation of inflammatory factors were studied by the expression level of IL-1? and TNF-? through western blot.The effects of apelin-13 on the Synaptic plasticity were studied by the expression level of SYN and PSD-95 through western blot.The effects of apelin-13 on the regulation of neuroinflammation were studied by the expression level of IKK? and NF-?B through western blot.[result] Apelin-13 ameliorates depressive like behavior induced by stress co-treated with LPS.Apelin-13 ameliorates the increased adrenal weight ratio induced by stress co-treated with LPS.The high expression level of IBA-1 and GFAP induced by stress co-treated with LPS were decreased by apelin-13 i.c.v administration.The high expression level of IL-1? and TNF-? induced by stress co-treated with LPS were decreased by apelin-13 i.c.v administration.The increased expression level of SYN and PSD-95 induced by stress co-treat-with LPS were decreased by apelin-13 i.c.v administration.The increased expression level of IKK? and NF-?B induced by stress co-treat-with LPS were decreased by apelin-13 i.c.v administration.[Conclusion] Apelin-13 can ameliorates the depressive like behavior and neuroinflammation induced by stress co-treated with LPS.