Activation of alveolar macrophages and peripheral red blood cells in rats exposed to fibers/particles

Abstract

The cytotoxic and oxidative responses of crocidolite and chrysotile asbestos fibers and ultrafine titanium dioxide (UF–TiO 2) particles were measured in alveolar macrophages (AM) and peripheral red blood cells (RBC) of rat after 30 days with a single intratracheal exposure (5 mg). The following responses were observed one month after fiber/particle instillation: (1) AM population increased; (2) lactate dehydrogenase and acid phosphatase activities in cell free lung lavage fluid increased; (3) substances that react with hydrogen peroxide or thiobarbituric acid were elevated in both AM and peripheral RBC; (4) glutathione peroxidase, glutathione reductase, and catalase were altered in both AM and peripheral RBC; (5) glutathione and ascorbic acid decreased in both AM and peripheral RBC. A significant difference from negative controls was noted in all responses of the two fiber-exposed groups, and in most responses of the UF–TiO 2-exposed group. The level of responses to the three test substances suggested a decreasing order of toxicity, with crocidolite>chrysotile>UF–TiO 2.