Phagocytosis-induced 51Cr release from activated macrophages and blood mononuclears. Effect of colchicine and antioxidants.

The chromium-release test was adapted to the measurement of the cellular injury induced when activated macrophages phagocytose particulates. Macrophages obtained from rabbit lungs undergoing BCG-induced chronic inflammation released more chromium when incubated in the presence of phagocytosable particles than when incubated under resting conditions. Blood mononuclear cells, 40-60% monocytes, procured from the same BCG-injected animals, were less susceptible to phagocytosis-induced injury than the macrophages obtained from the lungs. The amount of chromium released by the activated macrophages was proportional to the number of particles present during incubation. In the presence of catalase, the amounts of chromium released by phagocytosing and resting macrophages were similar; in the presence of superoxide dismutase and cytochrome c, the amount of chromium released by phagocytosing macrophages was 13-35% less than the amount of chromium released by macrophages incubated without the antioxidants. In addition, colchicine, an inhibitor of degranulation also exerted partial inhibition of the chromium release. These results suggest that oxygen radicals and lysosomal contents contribute to the cellular injury that results from phagocytosis.