In vitro effects of crocidolite asbestos and wollastonite on pulmonary macrophages and serum complement

Chronic inhalation of asbestos has been associated with interstitial fibrotic lung disease. Wollastonite fibers are currently being used as industrial substitutes for asbestiform materials. Since the pulmonary macrophage has been implicated as a modulator of fibrotic lung disease, we have investigated in vitro effects of crocidolite asbestos and wollastonite on the viability, morphology, and functional capacities of pulmonary macrophages. In addition, we have measured the capacity of these dusts to activate complement in serum, using pulmonary macrophage chemotaxis as a bioassay for activation. Preliminary evidence suggests that complement activation by inhaled dusts promotes inflammation. Acute exposures to wollastonite and crocidolite fibers in vitro had little effect upon pulmonary macrophage viability but affected changes in morphology and phagocytic capacity. Incubation of the dusts with rat serum produced complement activation. The results of these studies suggest that crocidolite and wollastonite exposures in vitro have effects on pulmonary macrophages which may simulate events occurring in the lung following dust exposures.