Reaction of macrophages activated by agents in vivo to quartz dust in vitro.

A comparative study was made of the cytotoxic action of quartz dust in vitro on macrophages activated in vivo by intraperitoneal inoculation of physiological saline, thioglycolate and starch. The liberation of lactate dehydrogenase (LDH) into the supernatant culture medium, adherence to a plastic surface, extent of acid dye exclusion and ultrastructural alteration in the surface morphology of macrophages were taken as parameters of the cytotoxic action of the dusts. Thioglycolate and starch stimulated cells when exposed in vitro to quartz dust released more LDH into the supernatant culture medium and resulted in a greater decrease in macrophage adherence than similarly exposed cells derived from saline stimulated animals. No difference was observed between cells obtained from differently stimulated animals in increased acid dye uptake, loss of surface filopodia and rounding of cells which phagocytosed quartz particles. The results show that quartz is cytotoxic for macrophages, irrespective of their degree of activation and the extent of damage induced is related to the chemical agent used for activation of macrophages in vivo.