Abstract
The present study aimed to determine whether hesperidin, a plant-based active flavanone
found in citrus fruits, can prevent high glucose-induced retinal pigment epithelial
(RPE) cell impairment. Cultured human RPE cells (ARPE-19) were exposed to a normal
glucose concentration (5.5 mM) for 4 d and then soaked in either normal (5.5 mM) or
high (33.3 mM) concentrations of D-glucose with or without different concentrations
of hesperidin (10, 20, or 40 µM) for another 48 h. The survival rates of the cells
were measured using a 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide
reduction assay. With the help of a fluorescent probe, the intracellular production
of reactive oxygen species (ROS) was evaluated. Colorimetric assay kits were used
to assess the antioxidant enzyme activities, and western blotting was used to measure
the expression of apoptosis-related protein. Hesperidin was effective in inhibiting
high glucose-induced ROS production, preventing loss of cell viability, and promoting
the endogenous antioxidant defense components, including glutathione peroxidase, superoxide
dismutase, catalase, and glutathione, in a concentration-dependent manner. Furthermore,
high glucose triggered cell apoptosis via the upregulation of caspase-9/3, enhancement
of cytochrome c release into the cytosol, and subsequent interruption of the Bax/Bcl-2 balance. These
detrimental effects were ameliorated by hesperidin in a concentration-dependent manner.
We conclude that through the scavenging of ROS and modulation of the mitochondria-mediated
apoptotic pathway, hesperidin may protect RPE cells from high glucose-induced injury
and thus may be a candidate in preventing the visual impairment caused by diabetic
retinopathy.
Key words
hesperidin - high glucose - human retinal pigment epithelial cells - reactive oxygen
species - apoptosis - diabetic retinopathy
