title: In vivo bioassays of acute asbestosis and its correlation with ESR spectroscopy and imaging in redox status.
abstract: In vivo electron spin resonance (ESR) spectroscopy and whole body imaging were used to investigate the toxicity of biological reactions and organ specific oxidative changes associated with the development of acute asbestosis. Pathogen-free mice were exposed to 100 microg of crocidolite asbestos suspended in 50 microL of a 0.9% NaCl solution by aspiration. The bio-assay group had broncho-alveolar lavage (BAL) and serum draws performed on control and treated mice at 1, 3, and 7 days post-instillation. The ESR spectroscopic measurements and whole body imaging were performed with a separate group of mice at the same time points. Bio-assays included measurements of albumin, lactate dehydrogenase (LDH), N-acetyl-beta-D-glucoaminidase (NAG), and catalase in acellular lavage fluids, and total antioxidants status in blood serum. ESR spectroscopic and imaging measurements were performed after intraperitoneal injection of 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-15N-1-oxyl (TEMPOL) or 3-carbamoylproxyl (3-CP) nitroxides at a final concentration of 344 mg/kg body weight. Albumin showed a significant increase in BAL fluid at the 3 day exposure time point. The presence of this protein in lavage fluid indicates that the gas/blood barrier has been damaged in the lung. LDH in BAL fluid also exhibited a significant increase at 3 days post-exposure, an indication of enhanced cell membrane damage in the lung. Similar results were observed for NAG, a lysosomal enzyme, implying activation of phagocytic cells. Contemporaneously with the development of acute asbestosis at day 3 post-exposure, there were significant increases in the levels of total antioxidants in the serum and catalase in the BAL fluid. Significant impairment in the ability of asbestos exposed animals to clear TEMPOL radical during acute disease progression was evident at days 1 and 3 post exposure. ESR image measurements provided information on the location and distribution of the 3-CP label within the lungs and heart of the mouse and its clearance over time. Bioassays in concert with ESR spectroscopy and imaging presented in this study provide congruent data on the early acute phase of pulmonary injury and oxidant generation in response to asbestos exposure and their decline after 7 days. The increased levels of total antioxidants in the serum and catalase in BAL fluid correlated with the reduction in the clearance rate for TEMPOL, suggesting that a change in the redox status of the lung is associated with lung injury induced by asbestos.
authors.affiliation: Pathology and Physiology Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505-2888, USA.
authors.forename: Stephen S
authors.initials: SS
authors.lastname: Leonard
authors.forename: Kristina
authors.initials: K
authors.lastname: Mowrey
authors.forename: Donna
authors.initials: D
authors.lastname: Pack
authors.forename: Xianglin
authors.initials: X
authors.lastname: Shi
authors.forename: Vince
authors.initials: V
authors.lastname: Castranova
authors.forename: Periannan
authors.initials: P
authors.lastname: Kuppusamy
authors.forename: Val
authors.initials: V
authors.lastname: Vallyathan
mesh_terms: D000208:Acute Disease; D000818:Animals; D001194:Asbestos / Q000494:pharmacology; D001195:Asbestosis / Q000097:blood / Q000175:diagnosis* / Q000201:enzymology / Q000378:metabolism; D001681:Biological Assay / Q000379:methods*; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D002374:Catalase / Q000378:metabolism; D003497:Cyclic N-Oxides / Q000378:metabolism / Q000493:pharmacokinetics; D003952:Diagnostic Imaging; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D051379:Mice; D009589:Nitrogen Oxides / Q000032:analysis / Q000378:metabolism; D010084:Oxidation-Reduction; D013113:Spin Labels; D013997:Time Factors
chemical_list: D003497:Cyclic N-Oxides; D009589:Nitrogen Oxides; D013113:Spin Labels; D001194:Asbestos; D007770:L-Lactate Dehydrogenase; D002374:Catalase; C039900:nitroxyl; C001803:tempol