muramidase and nickel-chloride

Lung macrophages lavaged from 7 rabbits were incubated with 0, 3, 6, 12 and 24 micrograms/ml of nickel as NiCl2 and macrophages from 4 rabbits were incubated with 0, 0.1, 1, 3 and 6 micrograms/ml of cadmium as CdCl2. After 2 days lysozyme activity in the medium in which the macrophages were cultivated, was estimated using a technique with agar plates prepared with heat-killed Micrococcus lysodeikticus. Macrophage morphology was examined by scanning and transmission electron microscopy. For nickel there was a dose-related inverse relationship between the lysozyme activity and concentration of nickel. Many macrophages exposed to the higher nickel concentrations had a rounded form and, thus, the surface area of each cell which came in contact with the glass appeared to be less than that for control macrophages. There was, however, no increase in the number of macrophages detached from their glass support. Cadmium exposure did not influence lysozyme levels of activity, in spite of morphological indications of cell toxicity. From the present study we conclude that the decreased lysozyme activity seen previously in vivo after nickel inhalation is likely to be due to a direct effect of nickel ions on macrophages and that the increased lysozyme activity seen in vivo after cadmium inhalation is probably a secondary effect, subsequent to inflammation.

Topics: Animals; Cadmium; Cadmium Chloride; In Vitro Techniques; Macrophages; Male; Microscopy, Electron; Muramidase; Nickel; Pulmonary Alveoli; Rabbits

Groups of rabbits were exposed to chlorides of nickel, cadmium, copper, and cobalt at concentrations ranging from 0.2 to 0.6 mg/m3 (as metal) for 4-6 weeks (5 days/week, 6 hr/day). Activity of lysozyme (muramidase) in lavage fluid, in alveolar macrophages, and in culture medium from macrophages incubated at 37 degrees C for 1 and 20 hr was estimated using the lyso-plate technique, agar plates with heat-killed Micrococcus lysodeikticus. In the nickel-exposed rabbits lysozyme activity in the mucous membrane from the left main bronchus was also estimated. Following nickel exposure the lysozyme level was significantly decreased in lavage fluid, macrophages, and in culture medium from incubated macrophages but remained unchanged in the mucous membrane. After exposure to cadmium, copper, and cobalt, lysozyme levels increased or were unchanged.

Topics: Animals; Cadmium; Cadmium Chloride; Cobalt; Copper; Lung; Macrophages; Male; Mucous Membrane; Muramidase; Nickel; Rabbits