Low glutathione peroxidase in rdl mouse retina increases oxidative stress and proteases

Malondialdehyde, reduced glutathione, glutathione peroxidase, glutathione reductase and cysteine protease cathepsins at postnatal (PN) days 2, 7, 14, 21 and 28 in controls (wt) and the retinal degeneration 1 (rd1) mouse model for retinitis pigmentosa retinas were measured to determine oxidative stress. In PN28 wt and PN2 rd1 retinas, elevated malondialdehyde and low glutathione peroxidase activity indicate higher oxidative load, despite higher reduced glutathione in PN2 rd1 retinas. This is due to physiological exposure to light and retinal vascular/neural restructuring, respectively. Compared with wt retinas, relatively high malondialdehyde at PN2 and cathepsin levels at PN14, 21 and 28 in rd1 retinas indicate that cells of the residual inner retina also contribute to the oxidative stress and retinal degeneration.