Antioxidant Injection May Help in Retinitis Pigmentosa
Injected antioxidant mixture increases cone cell density and restores some function in mouse model
WEDNESDAY, July 19 (HealthDay News) -- Antioxidant therapy may help prevent cone cell death and retinal degeneration associated with retinitis pigmentosa, according to a report published online July 18 in the Proceedings of the National Academy of Sciences Early Edition.
In the study, Peter A. Campochiaro, M.D., and colleagues from the Johns Hopkins University School of Medicine in Baltimore, used a mouse model of retinitis pigmentosa to test the hypothesis that cone cells die from oxidative damage. Oxygen levels rise in the retina as neighboring, oxygen-consuming rod cells die.
Daily injections of an antioxidant mixture of alpha-tocopherol (200 mg/kg), ascorbic acid (250 mg/kg), Mn(III) tetrakis (4-benzoic acid) porphyrin (10 mg/kg) and alpha-lipoic acid (100 mg/kg) starting at postnatal day 18 reduced the level of the oxidative damage marker acrolein by day 35, increased cone cell density and preserved some cone cell function compared with control. Single injections of alpha-tocopherol or alpha-lipoic acid alone also caused an increase in cone cell density.
"These data support the hypothesis that gradual cone cell death after rod cell death in retinitis pigmentosa is due to oxidative damage, and that antioxidant therapy may provide benefit," the authors write. However, "much more is needed to translate this finding into a useful treatment for patients," including understanding proper timing of treatment and development of delivery methods.