摘要
Apelin-13 is a novel endogenous ligand for an angiotensin-like orphan G-protein coupled receptor,and it may be neuroprotective against cerebral ischemia injury.However,the precise mechanisms of the effects of apelin-13 remain to be elucidated.To investigate the effects of apelin-13 on apoptosis and autophagy in models of cerebral ischemia/reperfusion injury,a rat model was established by middle cerebral artery occlusion.Apelin-13(50μg/kg)was injected into the right ventricle as a treatment.In addition,an SH-SY5Y cell model was established by oxygen-glucose deprivation/reperfusion,with cells first cultured in sugar-free medium with 95%N2 and 5%CO2 for 4 hours and then cultured in a normal environment with sugar-containing medium for 5 hours.This SH-SY5Y cell model was treated with 10-7 M apelin-13 for 5 hours.Results showed that apelin-13 protected against cerebral ischemia/reperfusion injury.Apelin-13 treatment alleviated neuronal apoptosis by increasing the ratio of Bcl-2/Bax and significantly decreasing cleaved caspase-3 expression.In addition,apelin-13 significantly inhibited excessive autophagy by regulating the expression of LC3B,p62,and Beclin1.Furthermore,the expression of Bcl-2 and the phosphatidylinositol-3-kinase(PI3K)/Akt/mammalian target of rapamycin(mTOR)pathway was markedly increased.Both LY294002(20μM)and rapamycin(500 nM),which are inhibitors of the PI3K/Akt/mTOR pathway,significantly attenuated the inhibition of autophagy and apoptosis caused by apelin-13.In conclusion,the findings of the present study suggest that Bcl-2 upregulation and mTOR signaling pathway activation lead to the inhibition of apoptosis and excessive autophagy.These effects are involved in apelin-13-induced neuroprotection against cerebral ischemia/reperfusion injury,both in vivo and in vitro.The study was approved by the Animal Ethical and Welfare Committee of Jining Medical University,China(approval No.2018-JS-001)in February 2018.
基金
supported by the National Natural Science Foundation of China,Nos.81870948(to BB),81671276(to BHC),81501018(to CMW)
the Natural Science Foundation of Shandong Province of China,No.ZR2014HL040(to BHC)
Program Supporting Foundation for Teachers’Research of Jining Medical University of China,No.JYFC2018KJ003(to SSD).