Figure 5. Effects of berberine on oxidative stress in human retinal endothelial cells (HRECs). Berberine (A) restored antioxidant enzyme activities including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) and reduced malondialdehyde (MDA) content, (B) inhibited expression of inducible nitric oxide synthase (iNOS), and (C) decreased iNOS activity in high glucose. The density of each band was measured and compared to that of the internal control, β–actin. * p<0.05 between low-glucose- and high-glucose-treated cells; ^† p<0.05 between berberine-treated and non-treated cells cultured in high glucose.