Abstract
Purpose: :
Oxidative stress is suggested to be one of the key factors in the pathogenesis of age–related macular degeneration (AMD). We previously showed that oxidized phospholipids increased in AMD eyes compared with age–matched normal eyes. To establish an AMD animal model, we attempted to induce the oxidation of phospholipids in mouse retina by irradiating blue–light.
Methods: :
BALB/c mice were exposed to a blue–light–emitting diode (illuminance: 5 mW/cm2, transmission peak wavelength: 480 nm) continuously for 30 days in a specially designed shadow–free cage. To detect oxidized phospholipids, immunohistochemistry with the anti–oxidized phosphatidylcholine antibody, DLH3, was performed on cryosections of the eye. Oxidized phospholipids were measured by competitive ELISA. Mice caged under normal light served as a control.
Results: :
Positive staining for oxidized phospholipids was observed in the outer nuclear layer (ONL) and retinal pigment epithelium (RPE) of the blue–light–exposed eyes, while control eyes showed minimal immunoreactivity. Long term blue–light exposure caused thinning of the ONL and photoreceptor layer. Competitive ELISA showed that blue–light exposure induced a 2.0–fold increase in oxidized phospholipids compared with control.
Conclusions: :
These results indicate that long term blue–light irradiation induces the oxidation of phospholipids in the ONL and RPE of mice. Blue–light may be useful for developing an animal model of AMD.
Keywords: age-related macular degeneration • oxidation/oxidative or free radical damage • lipids