Protection of quercetin against hyperbaric oxygen-induced apoptosis of human lens epithelial cell and its mechanism / 中华实验眼科杂志

ABSTRACT

Background Oxidative stress-induced apoptosis of human lens epithelial cells (LECs) is associated with c-Jun N terminal kinase (JNK) pathway.Quercetin possesses the antioxidation by inhibiting the JNK pathway.However,whether quercetin can protect LECs from the oxygen-induced damage is still not proved.Objective This study attempted to invatigate the effects and its mechanism of quercetin against hyperbaric oxygeninduced LECs apoptosis. Methods Human LECs line SRA01/04 was cultivated and passaged in MEM medium containing 10％ fetal bovine serum and 0.5％ non-essential amino acids for 2 hours,with or without 20 μmol/LSP600125 or 1 μmol/L quercetin prior to exposure to hyperbaric oxygen.Each exposure session remained 6 hours in 99％ O2 and 1％CO2 with a pressure chamber at 588 kPa.The viability of human LECs was detected by MTT.Cell apoptosis was assessed by flow cytometer using Annexin V-FITC apoptosis detection.The expression of JNK/p-JNK,c-Jun/p-c-Jun,caspase 3 and caspase 9 were detected by Western blot. Results LECs viability (A570 ) was 0.835 ±0.082,0.450±0.083,0.654±0.079,0.649±0.090 respectively in the blank control group,hyperbaric oxygen exposed group,hyperbaric oxygen+SP600125 group and hyperbaric oxygen+quercetin group.The A570 in the hyperbaric oxygen exposed group was significantly lower than the blank control group ( P =0.000),but those in hyperbaric oxygen + SP600125 group and hyperbaric oxygen+quercetin group were significantly higher than the hyperbaric oxygen exposed group ( P =0.003,0.002 ).The numbers of apoptosis cells were 3.17 ±0.74,19.77 ± 1.44,8.45 ±0.93,7.79 ±0.78 respectively in the blank control group,hyperbaric oxygen exposed group,hyperbaric oxygen+SP600125 group and hyperbaric oxygen+quercetin group.Apoptotic LECs were significantly increased in the hyperbaric oxygen exposed group compared with the blank control group ( P=0.000),but those in the hyperbaric oxygen+SP600125 group and hyperbaric oxygen+quercetin group were significantly reduced in comparison with hyperbaric oxygen exposed group (both P=0.000).In additional,expressions of p-JNK,p-c-Jun,caspase 3 and caspase 9 proteins in the cells were elevated in the hyperbaric oxygen exposed group compared with the blank control group (all P =0.000 ),however,those in the hyperbaric oxygen + SP600125 group and hyperbaric oxygen + quercetin group were declined when compared with the hyperbaric oxygen exposed group( all P＜0.05 ). Conclusions JNK pathway is involved in the apoptotic procedure of human LECs induced by oxygen stress.SP600125 and certain concentration of quercetin can interdict the JNK signal pathway and endogenous apoptosis of LECs and further alleviate hyperbaric oxygen-induced damage of LECs.