OZONE-INDUCED LIPID-PEROXIDATION AND MEMBRANE LEAKAGE IN ISOLATED RAT ALVEOLAR MACROPHAGES - PROTECTIVE EFFECTS OF TAURINE

Preincubation of alveolar macrophages in the presence of taurine resulted in a significant elevation of the intracellular content of this nutrient. Ozone exposure was associated with further increases in free intracellular taurine content. This mobilization of taurine seems to be a defense response to oxidants, since taurine supplementation decreased oxidant injury resulting from exposure of these cells to 0.45 ppm ozone for 30 min. Results indicate that taurine enrichment (100, 250, or 500-mu-M extracellular taurine) enhanced the ability of ozone-exposed cells to exclude trypan blue dye, decreased lipid peroxidation, lessened the ozone-induced decline in total ATPase, and decreased the leakage of glutathione. Taurine supplementation also decreased protein leakage and lessened the ozone-induced decline in Na+/K+ ATPase but only with 100-mu-M extracellular taurine (i.e., the plasma level of this nutrient). These data suggest that taurine is mobilized from the bound to free state in response to ozone exposure and that it acts to protect alveolar macrophages from ozone-induced damage. The data are consistent with the theory that taurine acts as a membrane stabilizer and/or an antioxidant.