Association between erythrocytosis and renal cancers in rats following intrarenal injection of nickel compounds.

Seventeen nickel compounds were administered to Fischer-344 rats (N = 270) by intrarenal injection (7 mg Ni/rat); the compounds included nickel sulfides, selenides, arsenides, oxide, antimonide, telluride, titanate, ferronickel alloy and metallic nickel dust. Erythrocytosis, as defined by peak hematocrit values that averaged greater than 55% during 1-4 months post-injection, occurred in nine of 17 Ni-treated groups (NiS2, beta NiS, alpha Ni3S2, Ni4FeS4, NiSe, Ni3Se2, NiAsS, NiO, Ni dust). Renal cancers (N = 23) developed within 2 years post-injection in nine of 17 Ni-treated groups (NiS2, beta NiS, alpha Ni3S2, Ni4FeS4, NiSe, Ni3Se2, NiAsS, NiAs, NiFe alloy). The renal cancers included eight fibrosarcomas, five mesangial cell sarcomas, two renal cell carcinomas, two carcinosarcomas, two leiomyosarcomas, two undifferentiated sarcomas, one rhabdomyosarcoma and one nephroblastoma. No erythrocytosis or renal cancers occurred in control rats (N = 97) in three groups treated with the vehicles or metallic iron dust. Rank correlation (p less than 0.0001) was observed between the incidences of erythrocytosis and renal cancers in the 17 Ni-treated groups. Rank correlation (p less than 0.001) was observed between the present incidences of renal cancers and the sarcoma incidences previously reported following intramuscular administration of the 17 nickel compounds to Fischer-344 rats (14 mg Ni/rat). The incidences of renal cancer were not correlated with the mass-fractions of nickel in the 17 compounds, the dissolution half-times of the compounds in rat serum or renal cytosol, or the phagocytic indices of the compounds in rat peritoneal macrophages.