LIPOSOMAL ALPHA-TOCOPHEROL ALLEVIATES THE PROGRESSION OF PARAQUAT-INDUCED LUNG DAMAGE

The present study was carried out to investigate the efficacy of lipos ome-associated alpha-tocopherol in treating pulmonary damage caused by paraquat exposure. alpha-Tocopherol liposomes (8 mg alpha-tocopherol/ kg body weight) or plain liposomes were intratracheally instilled into the lungs of rats 24 h after paraquat treatment (20 mg/kg, ip); treat ed animals were killed 8, 24 or 48 h after administration of the lipos omal preparations. Lungs of animals exposed to paraquat were extensive ly damaged as evidenced by an increase in lung weight and decreases in pulmonary angiotensin converting enzyme and alkaline phosphatase acti vities. Also, paraquat treatment resulted in a significant reduction i n glutathione (GSH) concentration in the lung and an elevation in micr osomal lipid peroxidation levels, as measured by the formation of dien e conjugates. Treatment of paraquat-injected rats with plain liposomes did not significantly alter paraquat-induced changes of all parameter s examined. On the other hand, treatment of rats with alpha-tocopherol liposomes, 24 h after paraquat administration, resulted in a signific ant increase in pulmonary alpha-tocopherol concentrations as well as a reduction in paraquat-induced changes in lipid peroxidation, GSH conc entration, and lung angiotensin converting enzyme and alkaline phospha tase activities. The results of the present study suggest that alpha-t ocopherol administered directly to the lung in a liposomal form, may s erve as a potentially effective pharmacological agent in the treatment of paraquat-induced lung injury.