Role of Surface Complexed Iron in Oxidant Generation and Lung InflammationInduced by Silicates

摘要

The hypothesis was tested that silica and silicate dusts complex iron on theirsurface and that this iron increases (1) in vitro oxidant generation, and mediator release by alveolar macrophages, and (2) acute inflammatory lung injury. Silica and silicates were found to complex more than ten times the Fe(3+) onto their surfaces than did a biologically inactive dust, titanium dioxide. In vivo generation of oxidants by alveolar macrophages measured after exposure to dusts was increased by surface complexed iron. Also, acute inflammatory lung injury after intratracheal injection of silica dusts was made more severe by surface iron. The authors conclude that silica and silicate surfaces complex Fe(3+) to increase oxidant generation and mediator release by alveolar macrophages, and to increase acute lung injury in the rat.