© 1982 Oxford University Press
research-article |
Phagocytosis of particulate nickel compounds by rat peritoneal macrophages in vitro
Departments of Laboratory Medicine and Pharmacology, University of Connecticut School of Medicine Farmington, CT 06032, USA
1To whom reprint requests should be sent at The University of Connecticut School of Medicine, 263 Farmington Avenue, Farmington, CT 06032, USA.
Phagocytic indices of 17 nickel compounds were measured in vitro in monolayer cultures of rat peritoneal macrophages. The macrophages were exposed for 1 h at 37°C to particles (1.5 µm median diameter) of the nickel compounds, at concentrations of 10 µg/ml of medium (2 µg/cm2 of monolayer). Phagocytic indices (i.e., the percentages of macrophages with one or more engulfed particles) ranged from 69% (NiO) to 3% (amorphous NiS). In order of decreasing phagocytic indices, the 17 nickel compounds were ranked as follows: NiO > Ni4FeS4 > NiTiO3 > NiSe > 
Ni3S2 > Ni > Ni5As2 > NiS2 > NiFe alloy > NiSb > Ni11As8 > Ni3Se2 > ßNiS > NiTe > NiAs > NiAsS > amorphous NiS. Rank-correlation (P <0.03) was observed between the phagocytic indices of the nickel compounds and their dissolution halftimes in rat serum. Nickel subsulfide, Ni3S2, was a notable exception to the general concordance between phagocytic indices and dissolution half-times: Ni3S2 was avidly phagocytized by macrophages, yet it had one of the shortest dissolution half-times. Preliminary results of carcinogenesis tests of 14 of the nickel compounds do not indicate significant rank-correlation between the phagocytic indices of the nickel compounds and the sarcoma incidences at 1 yr after i.m. administration of the compounds to rats.