Effects of pentoxifylline on active oxygen-induced sister-chromatid exchange.

Active oxygens cause major tissue damages in a number of distress syndromes. Pentoxifyline (POF) and its metabolites, a methylxanthine derivative, are inhibitors of superoxide anion production in stimulated human leukocytes. Examination was made of the effects of POF on the genotoxic actions of active oxygens. The frequency of sister-chromatid exchanges (SCEs) induced by paraquat (PQ), a generator of superoxide anions was significantly reduced in cultured Chinese hamster lung cells (CHL/IU) pretreated with POF. POF metabolite samples were also effective. Superoxide anion scavenging effect of POF were found at 0.1 mM, and it was more potent than that of POF metabolite samples. POF and its metabolite sample inhibited xanthine oxidase (XOD) at 1 mM but not at 0.1 mM. POF would thus appear to protect cells from the toxic effects of active oxygens on chromosomes and tissue damage by not only inhibition of active oxygen production in leukocytes but also by scavenging activity of active oxygens.