Generation of Reactive Oxygen Species by Quartz Particles and Its Implication for Cellular Damage

Abstract

Abstract Using wet analytical chemistry and electron spin resonance spin trapping, we have shown that aqueous suspensions of freshly fractured quartz particles generated hydrogen peroxide, hydroxyl radical, superoxide radical, and singlet oxygen. Superoxide dismutase partially inhibited the hydroxyl radical yield, whereas catalase suppressed it. Hydrogen peroxide enhanced the hydroxyl radical generation, while deferoxamine decreased it. Oxygen consumption measurements showed that freshly fractured quartz particles consumed molecular oxygen. Electrophoretic assays showed that freshly fractured quartz particles induced DNA double-strand breakage, which was inhibited by catalase. In an argon atmosphere DNA damage was suppressed, showing that molecular oxygen is required for quartz-induced DNA damage. Quartz particles also caused dose-dependent lipid peroxidation as measured by malondialdehyde formation. Superoxide dismutase, catalase, and sodium benzoate inhibited quartz-induced lipid peroxidation by 49, 52, and 75 percent, respectively. The results demonstrate that reaction of freshly fractured quartz particles with aqueous medium and hydrogen peroxide generates reactive oxygen species, which may play an important role in the mechanism of quartz-induced cellular injury. Shi, X.; Mao, Y.; Daniel, L.N.; Saffiotti, U.; Dalal, N.S.; Vallyathan, V.: Generation of Reactive Oxygen Species by Quartz Particles and Its Implication for Cellular Damage. Appl. Occup. Environ. Hyg. 10(12):1138–1144; 1995.