ABSTRACT
Objective To investigate whether alpha-lipoic acid (ALA) possesses neuroprotective effects against high glucose-induced damage in vitro.Methods The cultured human lens epithelial cells (HLEC-B3 cells) were divided into normal control group,high glucose group and ALA group.Normal control group left untreated,ALA group was pretreated with different concentrations of ALA (25 μmol · L-1,50 μmol · L-1,100 μmol · L-1) for 1h,and then ALA group and high glucose group were cultured under high glucose conditions for 48h.After above treatment,the activity of lens epithelial cells in each group was detected immediately by MTT,and the changes in intracellular reactive oxygen species (ROS) were detected by flow cytometry.In addition,the expression of manganese superoxide dismutase (MnSOD) was detected by Western blot and RT-PCR in all groups.Results The activity of HLEC-B3 cells in high glucose group was 53.60％ ±4.10％,which was significantly lower than that in normal control group (P ＜ 0.01).The cell viability in 25 μmol · L-1,50 μmol · L-1,100 μmol · L-1 ALA group was 65.30％ ± 3.70％,72.70％ ± 4.90％ and 83.40％ ± 3.60％,respectively,all which were higher than those in the high glucose group (all P ＜ 0.05).Flow cytometry showed that intracellular ROS level in the high glucose group was significantly higher than that in the normal control group (P ＜ 0.01),but ROS levels were decreased to 14.70％ ±0.70％,8.70％ ±0.87％,5.20％ ±0.53％ after25 μmol· L-1,50 μmol· L-1,100 μmol · L-1 ALA treatment,respectively,with significant difference (all P ＜ 0.01).RT-PCR and Western blot results indicated that the relative expression of MnSOD mRNA and protein in the high glucose group was significantly lower than that in the normal control group (all P ＜ 0.01).Compared with the high glucose group,MnSOD mRNA and protein relative expression levels were significantly increased to 0.63 ± 0.06,0.71 ± 0.06,0.84 ± 0.04,and 0.25 ± 0.03,0.31 ± 0.02,0.45 ± 0.04,respectively (all P ＜ 0.05).In addition,the protective effects of ALA (25-100 μmol · L-1) on HLEC-B3 cells induced by high glucose was in a dose-dependent manner.Conclusion ALA has a protective effect on human lens epithelial cell line HLEC-B3 cultured in high glucose condition,and this protective effect may be achieved by increasing the expression level of intracellular MnSOD.