CURCUMIN PROTECTS AGAINST 4-HYDROXY-2-TRANS-NONENAL-INDUCED CATARACT FORMATION IN RAT LENSES

Age-related cataractogenesis is a significant health problem worldwide . Oxidative stress has been suggested to be a common underlying mechan ism of cataractogenesis, and augmentation of the antioxidant defenses of the ocular lens has been shown to prevent or delay cataractogenesis . The present studies were designed to test the efficacy of curcumin, an antioxidant present in the commonly used spice turmeric, in prevent ing cataractogenesis in an in vitro rat model. Rats were maintained on an AIN-76 diet (ICN Pharmaceuticals Inc, Cleveland) for 2 wk, after w hich they were given a daily dose of corn oil alone or 75 mg curcumin/ kg in corn oil for 14 d. Their lenses were removed and cultured for 72 h in vitro in the presence or absence of 100 mu mol 4-hydroxy-2-nonen al (4-HNE)/L, a highly electrophilic product of lipid peroxidation. Th e results of these studies showed that 4-HNE caused opacifications of cultured lenses as indicated by the measurements of transmitted light intensity using digital image analysis. However, the lenses from curcu min-treated rats were much more resistant to 4-HNE-induced opacificati on than were lenses from control animals. Curcumin treatment caused a significant induction of the glutathione S-transferase (GST) isozyme r GST8-8 in rat lens epithelium. Because rGST8-8 utilizes 4-HNE as a pre ferred substrate, we suggest that the protective effect of curcumin ma y be mediated through the induction of this CST isozyme. These studies suggest that curcumin may be an effective protective agent against ca taractogenesis induced by lipid peroxidation.