The protective effect of beta-casomorphin-7 via promoting Foxo1 activity and nuclear translocation in human lens...

To investigate the protective effect of beta-casomorphin-7 (β-CM-7) in oxidative stressed human lens epithelial cells (HLECs) and to explore the possible mechanism for oxidative stress in HLECs induced by high glucose.

We used HLECs to determine the effect of different concentrations of β-CM-7 on cell viability by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolimol/L bromide (MTT) assay. We used flow cytometry to determine the content of reactive oxygen species (ROS) induced by oxidative stress and a bioassay kit to determine the oxidant malondialdehyde (MDA) and antioxidant enzyme superoxide dismutase (SOD) levels. We used Western blotting and an immunofluorescence assay to determine the expression of Forkhead box o1 (Foxo1), SP1, and the related protein glutathione peroxidase (GSH-px) at the molecular biology level as well as their intracellular localization.

The expression of Foxo1 and SP1 was weakly expressed when the glucose concentration was 40 mM/L, but was highly expressed when cells were pre-treated with an appropriate concentration of β-CM-7. After pre-treatment with β-CM-7, the cells treated with 40 mM/L glucose for 48 h showed Foxo1 was transferred to the nucleus, and the expression of SP1 was increased. The content of ROS and MDA in the HLECs that were pre-treated with β-CM-7 was lower than in those that was not pre-treated (p <0.05). Accordingly, SOD was elevated in the cells pre-treated with β-CM-7. The relative expression of GSH-px increased with increases of Foxo1 and SP1.

β-CM-7 protects HLECs from oxidative damage by upregulating the relative expression of Foxo1 and promoting Foxo1 nuclear translocation.