N-acetyl L-cysteine attenuates oxidant-mediated toxicity induced by chrysotile fibers

Chrysotile, an important commercial variety of asbestos, is known to cause oxidative stress by enhancing production of hydrogen peroxide (H2O2) and thiobarbituric acid reactive substances (TBARS), depleting glutathione (GSH) and altering levels of GSH redox system enzymes. N-acetyl L-cysteine (NAC), a compound that increases GSH levels, protects cells against chrysotile toxicity. In the present study, rats were exposed intratracheally to a single dose (5 mg/rat) of chrysotile. This was followed by a daily dose of NAC 50 mg/kg. b.wt., i.p. At 1, 4, 8 and 16 days post chrysotile exposure lung lavage fluid was collected to determine H2O2 generation, TEARS production, GSH level and its redox system enzymes activities. A significant decrease in H2O2 and TEARS, an increase in GSH content and its redox system enzymes was observed in chrysotile + NAC animals in comparison to chrysotile-exposed animals. In this preliminary study it appears that NAC may be protecting cells against oxidative damage. This protection may be due to its ability to maintain intracellular GSH/oxidative scavenging capability. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.