(3R)-5,6,7-trihydroxy-3-isopropyl-3-methylisochroman-1-one ameliorates retinal degeneration in Pde6b rd10 mice.

As a severe photoreceptor-degenerative disease, retinitis pigmentosa (RP) is currently incurable and eventually leads to partial or complete blindness. (3R)-5,6,7-trihydroxy-3-isopropyl-3-methylisochroman-1-one (TIM) is a novel antioxidant isolated from the plant of Alpinia katsumadai Hayata, with protective effects on photoreceptor cells against lipoteichoic acid-induced damage through inhibiting oxidative stress. The present study was to further demonstrate whether TIM could ameliorate retinal degeneration of Pde6brd10 (rd10) mice, a mouse model of RP. rd10 mice were treated with TIM by intraperitoneal injection daily from postnatal Day 10 (P10) to P26. Retinal function was tested by electroretinography. Histology was evaluated by toluidine blue staining and TUNEL assay. Oxidative stress markers were measured by ELISA. Immunohistochemistry, real-time PCR, and western blotting were applied to explore the protective mechanism. Results showed TIM significantly improved the retinal function and decreased photoreceptor cell apoptosis in rd10 mice through reducing oxidative stress. For the first time, this study demonstrated the protective effects of TIM against retinal degeneration in rd10 mice, providing scientific rationale to use TIM treating the RP.