Occupational exposure to crystalline silica (quartz) bas been associated with oxidative lung damage and fibrosis. These oxidants seem be generated directly from silica particles as well as from silica-activated pbagocytes. Pentosidine is a non-enzymatic glyco-oxidation protein adduct that bas been Suggested as a biomarker for oxidative stress. The potential of pentosidine as a biomarker for silica-induced oxidant injmy and fibrosis has not been investigated. As a first step in assessing this possibility, the concentration of pentosidine was determined in the lungs of silica exposed rats. Rats were exposed to filtered air (control) or silica aerosol of 15 mg/m3 (hr/day, 5 days/week) and bronchoalveolar lavage samples and lung tissue were evaluated at various times throughout the 116 day exposure. Alveolar macrophage (AM) chemiluminence, a measure of AM activation and reactive oxygen species production, was higher in silica-exposed rats than controls. Lung lipid peroxidation, an indicator of oxidative damage, steadily increased during exposure and was significantly elevated above control after 41 days exposure. Lung hydroxyproline, a marker of lung fibrosis, was significantly elevated above controls after 116 days exposure. In silica exposed rats, lung pentosidine levels were increased to 148% of control after 10 days exposure, and further increased to 239% by 116 days exposure. These data provide the first indication that lung pentosidine levels correlate with lung oxidative injury and fibrosis in silica-exposed rats. Further evaluation of pentosidine as a biomarker for silica-induced oxidative damage and fibrosis is warranted.
Animal-studies; Laboratory-animals; Statistical-analysis; Analytical-methods; Analytical-chemistry; Exposure-assessment; Toxicology; Toxins; Toxic-materials; Pulmonary-system-disorders; Pulmonary-disorders; Respiratory-system-disorders; Respiratory-irritants; Particulate-dust; Particulates; Dust-exposure; Dust-inhalation; Dust-particles; Airborne-dusts; Airborne-fibers; Airborne-particles; Silica-dusts; Silicates