Protective effect of XY99-5038 on hydrogen peroxide induced cell death in cultured retinal neurons.

XY99-5038 is a preparation from a specific formula provided by Dr. Yan Xin, a renowned Traditional Chinese Medicine specialist. This formulation has proven to be effective without side effects but has not been studied under rigorous laboratory conditions. In order to investigate the role of XY99-5038 in protecting neurons from degeneration, we used retinal neuronal culture as a model system to study the protective effects of XY99-5038 against hydrogen peroxide (H2O2) induced cytotoxicity. Basic fibroblast growth factor (bFGF), a potent neurotrophic factor, was employed as comparable agent. Retinas of 0-2 days old Sprague-Dawley rats were isolated, dissociated, and the neurons maintained for 2 weeks in a synthetic serum-free media. Cytotoxicity was determined by MTT (3,(4,5-dimethylthiazol-2-yl)2,5-diphenyl-tetrazolium bromide) and LDH (Lactate dehydrogenase) assays, whereas apoptotic cell death was evaluated by the TUNEL (TdT-mediated digoxigenin-dUTP nick-end labeling) assay. Treatment with H2O2 significantly induced death of retinal neurons. Pretreatment with XY99-5038 prior to insult greatly inhibited or attenuated H2O2 induced cytotoxicity and apoptosis. These effects were shown to be dose-dependent. Our data also show that the protective effect of XY99-5038 is more potent than that of bFGF. Our data suggest that XY99-5038 could be a potential agent in the treatment of disorders associated with oxidative damage.