Generation of metal-induced reactive oxygen species by residual oil fly ash.
Antonini-JM; Lewis-AB; Roberts-JR; Leonard-SS; Shi-X; Taylor-MD
Toxicologist 2002 Mar; 66(1-S):357
Inhalation of residual oil fly ash (ROFA) increases pulmonary morbidity in exposed workers. We examined the role of reactive oxygen species (ROS) in ROFA-induced lung injury. ROFA was collected from Boston Edison Co., Everett, MA. ROFA (ROFA-total) was suspended in saline, incubated for 24 hr at 37 degrees C, centrifuged, and separated into soluble (ROFA-sol) and insoluble (ROFA-insol) fractions. The generation of ROS from the ROFA samples was measured by electron spin resonance (ESR). Sprague-Dawley rats were intratracheally instilled with saline, ROFA-total, ROFA-sol, or ROFA-insol (1 mg/100 g body weight). Lung tissue and bronchoalveolar lavage cells were harvested at 4, 24, and 72 hr after instillation. Chemiluminescence (CL) of recovered cells was measured as an index of ROS production, and tissue lipid peroxidation was assayed to assess oxidative injury. Using a spin trap (DMPO), hydroxyl radicals were detected in the ROFA-total sample. Significantly more hydroxyl radicals were measured in ROFA-sol as compared to ROFA-insol. Superoxide anion and hydrogen peroxide were implicated in the production of the hydroxyl radicals. After treatment with the metal chelator, desferrioxamine, the production of hydroxyl radical was greatly diminished. None of the ROFA samples had an effect on CL or lipid peroxidation at 4 hr. Treatment with ROFA-total and ROFA-insol caused significant increases (p<0.05) in both CL (at 24 hr) and lipid peroxidation (at 24 and 72 hr) when compared to control. ROFA-sol significantly reduced (p<0.05) CL production at 72 hr after treatment and had no effect on lipid peroxidation at any time point. In summary, ROFA, particularly its soluble fraction, generated a metal-dependent hydroxyl radical as measured by cell-free ESR. However, cellular oxidant production and tissue injury were observed mostly with the ROFA-total and ROFA-insol particulate forms. ROS generated by ROFA-sol as measured by ESR appear not to play a major role in the lung injury caused after ROFA exposure.
Metal-compounds; Fly-ash; Pulmonary-system-disorders; Lung-disorders; Animal-studies; Laboratory-animals; Respiratory-system-disorders
Asthma and Chronic Obstructive Pulmonary Disease; Disease and Injury
The Toxicologist. Society of Toxicology 41st Annual Meeting and ToxExpo, March 17-21, 2002, Nashville, Tennessee
West Virginia University, Morgantown, WV