担鉄肺胞マクロファージの機能に関する研究 第2編 溶接フューム吸入モルモットにおける肺胞マクロファージの検討

In order to clarify the relation of iron-laden alveolar macrophages to the pathogenesis of arc welder's lung, kinetics and functions of guinea pig alveolar macrophages were assessed by whole-lung lavage 1, 4 and 8 weeks after the exposure to welding fume. Whole-lung lavage was performed also in unexposed guinea pigs as controls. The number of lavaged cells was low 1 week after exposure, but exceeded control levels 4 weeks after exposure and remained elevated thereafter. The percentage of polymorphonuclear leukocytes was high 1 and 8weeks after exposure, and that of macrophages was high 4 weeks after exposure. The iron-loading rate of alveolar macrophages was 0% in controls. It was elevated above 90% 1 week after exposure and remained elevated thereafter. Chemotaxis to zymosan activated serum and random migration of alveolar macrophages were maximal 1 week after exposure and were significantly greater (p<0.001) than with controls at all times. The chemotactic differential and chemotactic index were significantly low 4 and 8weeks after exposure (p<0.05, p<0.001), compared with those of controls. The phagocytosis of opsonized zymosan particles by alveolar macrophages were significantly lower (p<0.01), than controls at all times. There was no significant difference in β-galactosidase activity of alveolar macrophagesbetween controls and welding fume-exposed guinea pigs at any time. Superoxide production by alveolar macrophages was maximal 1 week after exposure and remained significantly high thereafter (p<0.05), compared with that for controls. Thus, exposure to welding fumes in vivo appears to induce acute and chronic inflammatory reactions and iron transport which are probably mediated by alveolar macrophages.