Effect of kerosene and its soot on the chrysotile-mediated toxicity to the rat alveolar macrophages

In order to examine the pulmonary toxicity of kerosene oil and its combustion product (soot) in asbestos-exposed rats, various biochemical and chemical parameters were assayed. Treatment of rats with a single intratracheal dose of chrysotile asbestos (5 mg) and kerosene (50 mu l) or its soot (5 mg) in combination led to an increased number of pulmonary alveolar macrophages (PAM), elevated levels of hydrogen peroxide, and thiobarbituric acid-reacting substances, alterations in the activities of primary (glutathione peroxidase and catalase) and secondary (glutathione reductase and glucose-g-phosphate dehydrogenase) endogenous antioxidant enzymes, and depletion in the levels of glutathione in PARI compared to the chrysotile, kerosene, or soot alone, These changes may indicate the generation of oxidative stress in the macrophages. The resulting oxidative stress may be subsequently critical in collapsing the cellular membrane, which may change the cell membrane permeability and may also damage the phagolysosomal membrane, thereby releasing the membrane bound enzymes as indicated by an increased leakage of intracellular acid phosphatase and lactate dehydrogenase. The injury to macrophages may trigger events that lead to lung fibrosis and/or malignancies in the exposed animals, This study may be helpful in understanding the etiology of certain clinical and pathological disorders in the population exposed simultaneously to both asbestos and kerosene or its combustion products. (C) 1997 Academic Press.