The physiological role of reactive oxygen species (ROS) in lens and corneal epithelial cells

Abstract

AbstractPurpose ROS have been shown to mediate growth factor mitogenic function in many cell types. This study is to explore if H2O2 (a stable ROS species) at low levels can promote proliferation in lens epithelial cells, and facilitate adhesion, migration, and wound healing in corneal epithelial cellsMethods Human lens epithelial (HLE) B3 cells were treated with H2O2 (0‐50 μM) and analyzed for cell proliferation by thymidine assay. H2O2 (0‐70 μM) treated primary rabbit corneal epithelial (RCE) cells were tested for viability by MTT assay, adhesion by centrifugation assay, focal contacts of vinculin and F‐actin by immunofluorescence. Activations of Src (pY416), EGF receptor (pY845), vinculin (pY1065), FAK (pY397 and pY576) were examined by immunoblotting. The cell migration was tested by a scratch wound method, while the cornea wound healing in vitro (pig), and in vivo (mouse) was examined by scraping off an area of the epithelial cells, and treated by H2O2 with and without N‐acetylcysteine (NAC)Results Compared with the untreated control, H2O2 at 20 μM stimulated HLEB3 cell proliferation. This level of H2O2 also enhanced RCE cell viability, facilitated adhesion and migration with activations of EGF receptor (Y845), and the downstream Src (pY416), FAK (Y576), and vinculin (Y1065). H2O2‐treated RCE cells also showed focal adhesion rich in vinculin, and stress fibers containing F‐actin. Low level of H2O2 induced a faster wound healing in cornea both in vitro and in vivo, and the healing was weakened if treated by H2O2 + NAC.Conclusion H2O2 at low levels can benefit both lens and corneal epithelial cells in growth and wound healing. This novel physiological function of H2O2 confirms the importance of redox balance for the general health of cells and tissues.