EFFECT OF N-ACETYLCYSTEINE ON THE OXIDATIVE BURST INDUCED BY PHAGOCYTOSIS OF BACTERIA IN HUMAN-LEUKOCYTES

The basal peroxide production and the oxidative burst induced by phago cytosis of opsonized E. coli was studied by flow cytometry using dihyd rorhodamine 123. The human leukocytes were incubated in the absence an d presence of N-acetylcysteine. The oxidative response to the phagocyt osis of bacteria differed among cell populations. Thus, 90% of granulo cytes and 50% of monocytes showed an oxidative burst iii response to o psonized bacteria while less than 1% of lymphocytes showed a fluoresce nce signal. N-Acetylcysteine (4.7, 9.5, 19, 38 or 76 mM) produced a do se-dependent inhibition of the oxidative response to phagocytosis in t he three cellular populations reaching almost complete inhibition for 76 mM. This protective effect of N-acetylcysteine against oxidative st ress in leukocytes was obtained without cytotoxicity (assessed by flow cytometry with staining with propidium iodide) or changes ill the pH of the medium. These results give further support to the antioxidant e ffect of N-acetylcysteine N-acetylcysteine in human peripheral blood c ells. (C) 1998 Prous Science. All rights reserved.