Generation of reactive oxygen species by process materials from indium-tin oxide production.
Fix-NR; Dunnick-KM; Badding-MA; Stefaniak-AB; Cummings-KJ; Castranova-V; Leonard-SS
Toxicologist 2013 Mar; 132(1):429
The transition metal indium has been used for decades for various applications including electronics, fusible alloys, and solar cells. Indium compounds usage has increased dramatically based on the rise in demand of touch screens and flat panel displays (LCD's). With this growth of industry, there is potential for increase of indium lung disease among workers who produce, use, or reclaim indium-tin oxide (ITO). Inhalation exposure of indium samples can occur during various times of manufacturing. Materials from different process stages were collected from an ITO production facility. While the pathogenesis of indium lung disease is unknown, previous work has suggested a role for reactive oxygen species (ROS). Chemical characteristics of the process materials will aid in determination of reactivity differences between compounds. Electron spin resonance (ESR), a common tool used for measuring ROS, was used in both acellular and cellular exposures. Acellular samples were evaluated by combining 10 mg/mL process material, phosphate buffered saline (PBS), 10mM hydrogen peroxide (H2O2), and 100mM DMPO (spin trap). RAW 264.7 mouse monocyte macrophages, DMPO, and the same concentration of composite were used in the cellular samples conducted in ESR. Scavengers and chelators were used to define radical mechanisms. Results indicated that ventilation dust (VD), tin-oxide (SnOX), and unsintered ITO (UITO) cause a greater increase in ROS production than the other process material. H2O2 and O2 consumption measurements were used to determine the source of the ROS. ESR studies combined with investigation of ROS production will help to determine the mechanisms behind indium lung disease. Data from this study will be used to determine possible hazards in occupational exposure of indium process material while increasing the understanding of indium lung disease.
Toxicology; Laboratory-techniques; Laboratory-testing; Exposure-assessment; Measurement-equipment; Materials-testing; Respiratory-system-disorders; Pulmonary-system-disorders; Lung-disorders; Lung-disease; Lung-function; Lung-cells; Metal-compounds; Transition-metals; Indium-compounds; Tin-oxides; Oxides; Oxidative-processes; Cell-cultures; Cellular-function; Cellular-reactions; Free-radicals; Inhalants; Phosphates; Hydroperoxides; Pyrroles; Methyl-compounds; Chelating-agents; Dusts; Chemical-composition; Chemical-reactions
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The Toxicologist. Society of Toxicology 52nd Annual Meeting and ToxExpo, March 10-14, 2013, San Antonio, Texas