Pulmonary responses of acute exposure to ultrafine iron particles in healthy adult rats

As critical constituents of ambient particulate matter, transition metals such as iron may play an important role in health outcomes associated with air pollution. The purpose of this study was to determine the respiratory effects of inhaled ultrafine iron particles in rats. Sprague Dawley rats 10-12 weeks of age were exposed by inhalation to iron particles (57 and 90 mug/m(3), respectively) or filtered air (FA) for 6 h/day for 3 days. The median diameter of particles generated was 72 nm. Exposure to iron particles at a concentration of go mug/m(3) resulted in a significant decrease in total antioxidant power along with a significant induction in ferritin expression, GST activity, and IL-1beta levels in lungs compared with lungs of the FA control or of animals exposed to iron particles at 57 mug/m(3). NFkappaB-DNA binding activity was elevated 1.3-fold compared with that of control animals following exposure to 90 mug/m(3) of iron, but this change was not statistically significant. We concluded that inhalation of iron particles leads to oxidative stress associated with a proinflammatory response in a dose-dependent manner. The activation of NFkappaB may be involved in iron-induced respiratory responses, but further studies are merited. (C) 2003 Wiley Periodicals, Inc.