The pineal secretory product melatonin reduces hydrogen peroxide-induced DNA damage in U-937 cells

Melatonin, the chief secretory product of the pineal gland, is a potent and efficient endogenous radical scavenger. Thus, melatonin was shown to prote ct different biomolecules, such as DNA, membrane lipids, and cytosolic prot eins, from oxidative damage induced by oxygen-derived free radicals. In ord er to study the protective role of melatonin in hydrogen peroxide (H2O2)-in duced DNA damage, U-937 cells were treated with different concentrations of H2O2, either in the presence or absence of melatonin, and DNA damage was a ssessed using the cytokinesis-block micronucleus technique. Melatonin dimin ished H2O2-induced micronuclei production both in short and long treatments . Additionally, melatonin concentrations higher than 1 mu M were capable of protecting cells from spontaneous micronuclei production. These data sugge st that melatonin, an endogenous antioxidant and nontoxic compound, may hav e an important role in protecting cells from genetic damage due to free rad icals, supporting the idea of this hormone as a possible therapeutic agent in preventing aging and age-related diseases.