ONE-YEAR FOLLOW-UP OF THE PHAGOCYTIC-ACTIVITY OF LEUKOCYTES AFTER EXPOSURE OF RATS TO ASBESTOS AND BASALT FIBERS

The phagocytic activity of leukocytes in peripheral blood was investig ated after 2, 24, and 48 hr; 1, 2, 4, and 8 weeks; and 6 and 12 months following intraperitoneal administration of asbestos and basalt fiber s to Wistar rats. Asbestos and basalt fibers differed in their effects on the parameters studied. Both granulocyte count and phagocytic acti vity of leukocytes during the 1-year dynamic follow-up in both dust-ex posed groups of animals changed in two phases, characterized by the in itial stimulation of the acute phase I, followed by the suppression of the parameters in the chronic phase II. Exposure to asbestos and basa lt fibers led, in phase II, to impairment of the phagocytic activity o f granulocytes. Asbestos fibers also significantly decreased phagocyti c activity of monocytes. Exposure to basalt fibers did not affect the phagocytic activity of monocytes in phase II. Results suggest that the monocytic component of leukocytes plays an important role in the deve lopment of diseases caused by exposure to fibrous dusts, but basalt fi bers have lesser biological effects than asbestos fibers.