Pathological reactions in lung, liver, thymus, and spleen of rats after subacute parenteral administration of nickel sulfate

Male Fischer-344 rats (10 to 12 rats per group) were given 14 i.m. injection of nickel sulfate (NiSO4) over a period of 26 days in order to delineate the two-year survival, body weight curves, hematocrit responses, and histopathological reactions, including carcinogenesis. Group A (vehicle controls) received the NaCl vehicle; Groups B, C, and D received NiSO4 solution at dosages of 63, 83, or 125 mumol per kg, respectively. Rats in Group D all died during the period from 4 to 32 days after the first injection; survival of rats in Groups B and C did not differ significantly from the controls (Group A). No differences were found at any time between the mean body weights or blood hematocrits of the NiSO4-treated groups vs. the controls. In Group D, histopathological lesions of the lung, liver, thymus, and spleen were consistently observed; these lesions were most severe in rats that died during the period from 22 to 32 days after the first injection. The lungs showed proliferation of alveolar lining cells, thickening of the alveolar wall, and proteinaceous alveolar exudate. The livers showed microvesicular steatosis, and necrotic hepatocytes were scattered throughout the lobules. Degeneration of lymphocytes, with pyknosis and karyorrhexis, was observed in the thymic cortex and the white pulp of the spleen. At necropsy, no significant differences were found between the NiSO4-treated rats of Groups B and C and the controls (Group A). No sarcomas or other neoplasms occurred near the injection sites in NiSO4-treated rats.(ABSTRACT TRUNCATED AT 250 WORDS)