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.
担鉄肺胞マクロファージ (iron-laden alveolar macrophage)
溶接フューム吸入モルモット (guinea pig)
welding fume exposure