Crystalline silica incubated in ascorbic acid acquires a higher cytotoxic potential.

Quartz incubated in an aqueous solution of ascorbic acid is partially dissolved and the potential to generate hydroxyl radicals from hydrogen peroxide is enhanced. In order to investigate whether the surface activation triggered by the treatment with ascorbic acid would also involve an enhancement in cell toxicity, a murine macrophage cell line (RAW 264.7) was exposed to untreated and ascorbic acid-treated quartz. Ascorbic acid pretreated quartz was more toxic than untreated quartz and all cells died within 24 hours after exposure. Tetrandrine (a Chinese drug employed to retard or reverse fibrotic lesions of silicosis in humans) partially reduced cell toxicity generated by ascorbic acid pretreated quartz.