Myocardial Protective Effects Of 5-aminolevulinic Acid And Sodium Ferric Citrate On Autophagy And Its Mechanism

Objective:The purpose of this study was to find out whether ALA/SFC can protect cardiac myocytes from hypoxia-induced apoptosis through HO-1 signaling via autophagy,and to explore its possible mechanisms and signaling pathways.Methods:Using ALA/SFC pretreatment HL-1 atrial myocardial cells of mice,and exposed to hypoxia state.Via the CCK-8 to determine cell survival,TUNEL to detected apoptosis,MDC staining to detect cell autophagy,and the experimental steps of ROS detection,western blot analysis,cell immunofluorescence staining,siRNA knockdown,to evaluate myocardial cell survival,expression level of HO-1,Nrf-2 and MAPKs,and autophagy level.By the above analysis we investigate the mechanism of ALA/SFC in the injury of mouse myocardial cell line(HL-1 cell)induced by hypoxia.Results:Apparently,ALA/SFC pretreatment has the effect of reduce hypoxia-induced cardiomyocyte apoptosis,reactive oxygen generation and mitochondrial damage,but increasing cell viability and autophagy.The expression of HO-1 in ALA/SFC is related to up-regulation of Nrf-2 and nuclear translocation,however the expression of HO-1 is notably reduced by Nrf-2 siRNA.Erk1/2,p38,and SAPK/JNK pathways are activated by ALA/SFC,and their specific inhibitors can notably reduce ALA/SFC-mediated HO-1 upregulation.Nrf-2 or HO-1 silencing and autophagy inhibitors LY294002 can eliminated ALA/AFC's protection against hypoxia-induced injury and reduced ALA/SFC induced autophagy.Conclusions:Our study demonstrated that ALA/SFC induced autophagy through HO-1 can protect cardiomyocytes from cell damage caused by hypoxia.ALA/SFC prevented hypoxia-induced cell death by inducing autophagy and improved mitochondrial proliferation and ROS production in hypoxia-induced HL-1 cells.In addition,ALA/SFC treatment can phosphorylate ERK1/2,p38,and SAPK/JNK,and simultaneously induce the expression of HO-1 and Nrf-2.The silencing of HO-1 by siRNA eliminates the autophagy induced by ALA/SFC.Our results suggest that ALA/SFC has a cardioprotective effect through autophagy induced by a cascade of MAPK-Nrf-2-HO-1 signals.