EFFECTS OF NICKEL HYDROXYCARBONATE ON ALVEOLAR MACROPHAGE FUNCTIONS

The metabolic effects of different concentrations of nickel hydroxycarbonate (NiHC) on guinea pig alveolar macrophages (GPAMs) were investigated. Exposure to high concentrations of NiHC (6.25 and 12.5 mu-g 10(-6) cells) led to cell vacuolization. Morphological changes were associated with a dramatic reduction in the steadystate level of cellular adenosine triphosphate (ATP), i.e. ATP levels were reduced by 35% (P < 0.001) and 53% (P < 0.01), respectively. Low concentrations of NiHC (0.0625 and 0.125 mu-g 10(-6) cells) did not induce morphological changes but increased cellular ATP content by 19% (P < 0.01) and 12% (P < 0.05), respectively. Effects of NiHC (0.125 and 6.25 mu-g 10-6 cells) on cell oxidative metabolism were studied. The chemiluminescence was significantly increased (P < 0.001) by the lower but not the higher concentration. A slight inhibition of total superoxide dismutase (P < 0.05) and a decrease of catalase activity were demonstrated (P < 0.05) for the high dose, while the low dose decreased the levels of reduced and total glutathione. In conclusion, the effects of NiHC on alveolar macrophages are characterized by an overproduction of free radicals for low concentrations and the depletion of cellular reserve energy, particularly ATP, for high concentrations.