Effect of L-Carnosine on 8-OH Deoxyguanosine Release by H2O2 in 3Y1 Rat Embryo Fibroblasts

L-Carnosine is abundantly present in vertebrate skeletal muscles. Its antioxidant role in the body has been of interest to nutritional biochemists. We investigated the release of 8-hydroxydeoxyguanosine (8-OH dG), one of the markers for in vivo oxidative DNA damage, by rat embryo fibroblasts in response to oxidative stressor H2O2 and L-carnosine. When fibroblasts were exposed only to H2O2 (10–500 μM) for 120 minutes varying patterns of 8-OH dG release were observed with increasing concentration of H2O2. At a concentration of 100 μM, H2O2 produced a dose-dependent increase in 8-OH dG release into the medium. Exposure of fibroblasts to 500 μM of H2O2, even for 30 minutes, resulted in irreversible cell death. The antioxidant effect of L-carnosine was measured by exposing the fibroblasts simultaneously to H2O2 (250 μM) and L-carnosine (10 or 30 mM) for 60 minutes. The 8-OH dG release from the fibroblasts treated with H2O2 and L-carnosine was markedly lower than that of fibroblasts treated with H2O2 only. We conclude that the antioxidant role of L-carnosine is probably executed via its inhibition of the formation of 8-OH dG.