Experimental Study Of L-carnitine Alleviates Oxidative Stress-related Damage By MAPK Signaling In Human Lens Epithelial Cells Exposure To H₂O₂

Purposes:Human lens epithelial cells（HLECs）are vulnerable to oxidative stress,which has deleterious effect on lens transparency,ultimately leading to cataract.L-carnitine（LC）is a substance that is essential to humans with powerful antioxidative properties in vivo and in vitro,but the impact of LC on human lens epithelial cells（HLECs）and its regulatory mechanism are still not unified.In this research,we aimed to evaluate the effect of LC on the human lens epithelial cells（HLECs）and its regulatory mechanism on cataractogenesis.Methods:The HLE B-3 were divided into the following five groups:（1）Control group:which was cultured in Ordinary medium.（2）Oxidation damage group:In addition to the above culture solution,the 250μmol/L concentration of H2O2 was added for 24h.（3）LC low concentration group:100μmol/L LC pretreated cells for 16h,the250μmol/L concentration of H2O2 was added for 24h,（4）LC medium concentration group:300μmol/L LC pretreated cells for 16h,the 250μmol/L concentration of H₂O₂was added for 24h,（5）LC high concentration group:500μmol/L LC pretreated cells for 16h,the 250μmol/L concentration of H2O2 was added for 24h.The cells were serum-starved 8 hours before treatment.CCK-8 assay was used to detection the cell viability.The cell viability was calculated in the light of the formula that cell viability（%）=[（As-Ab）]/[（Ac-Ab）.Among them,As was the average OD value of the experimental group,Ab was the average OD value of the blank group,Ac was the average OD value of the control group.DCFH-DA staining was carried out to determine the reactive oxygen species（ROS）production induced by H2O2 and LC.RT-PCR and Western Blot were performed to detect the expression levels of oxidative damage markers and antioxidant enzymes.Results:H2O2 could induce cell death and LC could inhibit the decrease of cell viability induced by H2O2.ROS overproduction was found when exposed to H2O2,LC supplementation greatly induceded the ROS through activation of antioxidant enzymes FoxO1,PRDX4 and CAT.LC suppressed the cell apoptosis and inflammation,the expression of caspase3 and IL-1 were inhibited.LC promoted the PCNA,CDK2 and CDK4 expression to rescue the cell proliferation after HLECs incubated with H2O2.EMT occurred when ROS accumulation,whereas the reversion of AQP1 and vimentin expression could be observed with LC supplementation.LC restoreed a balance between oxidant and antioxidant systems and the cell damage through MAPK signaling pathway.Conclusions:In conclusion,LC has the protective role in curbing oxidative damage and thus may be a potential therapeutic agent for cataract.