COMPARISON OF SOME BRONCHOALVEOLAR LAVAGE PARAMETERS AND HISTOLOGICAL-FINDINGS AFTER EXPOSURE OF RATS TO AMOSITE AND WOLLASTONITE FIBERS

Rats were exposed to fibrous dusts for 10 weeks (1 mg/week) and lavage parameters (the number of Le/ml of BAL, the number of AM/ml of BAL, p hagocytic activity and viability of AM, ratios of AM to GR, TNF-alpha release by lavaged AM), as well as histological findings were investig ated 3 months after tile first intratracheal instillation. While short -fibre wollastonite instillation did not influence significantly the p arameters studied, long-fibre wollastonite exposure significantly incr eased only the number of Le/ml of BAL. Short and long amosite fibres c aused different results in the parameters studied, with tile long fibr es being more effective. In comparison with tile control conditions, s hort amosite fibres significantly decreased the numbers of AM/ml of BA L and increased their phagocytic activity. Long: amosite fibres signif icantly increased the number of Le/ml of BAL and tile percentage of gr anulocytes (i.e. tile AM to GR ratios); whereas the number of AM/ml of BAL, phagocytic activity, viability of AM, and TNF-alpha levels in su pernatants of cultured leukocytes were significantly decreased. Admini stration of long amosite fibres resulted in the formation of giant cel l granulomas around alien bodies in tile lungs. The results of our stu dy indicate that long amosite fibres may contribute to immunosupressio n in an exposed host.