Exposure to stainless steel welding fume suppresses lung defense function after infection in rats.
Antonini-JM; Roberts-JR; Taylor-MD
Am J Respir Crit Care Med 2003 Apr; 167(7):A258
Pulmonary infections are increased in severity, duration, and frequency among full-time welders. The objective was to examine the mechanisms by which a stainless steel welding fume may alter lung defense against infection. At day 0, male Sprague-Dawley rats were intratracheally instilled with a manual metal arc, stainless steel welding fume (MMA-SS) at a concentration of 1.0 mg/100 g body weight or saline (vehicle control). At day 3, the MMA-SS- and saline-treated rats were intratracheally inoculated with 5,000 Listeria monocytogenes. At days 6, 8 and 10, left lungs were removed, homogenized, cultured overnight, and colony-forming units counted to assess pulmonary bacterial clearance. Right lungs were lavaged to recover phagocytes and lavage fluid to measure the production of the anti-microbial agent, nitric oxide (NO) and immuno-modulatory cytokines, including IL-2 and IL-10. Exposure to the fume before infection significantly slowed the pulmonary clearance of the bacteria and severely damaged the lungs compared to control. Phagocytic cell NO production and lavage fluid IL-2 were significantly reduced in the MMA-SS + L. monocytogenes group early after infection compared to the saline + L. monocytogenes group. Pretreatment with MMA-SS before infection caused a significant increase in lavage fluid IL-10. In conclusion, the MMA-SS-induced suppression of lung defense against infection in rats involves a reduction in cellular production of NO and IL-2 as well as an increase in anti-inflammatory IL-10 production.
Stainless-steel; Steel-industry; Steelworkers; Welding; Laboratory-animals; Animal-studies; Animals; Pulmonary-system-disorders; Welders; Welders-lung; Lung-disease; Lung-disorders; Lung-irritants
Abstract; Conference/Symposia Proceedings
Work Environment and Workforce: Mixed Exposures
American Journal of Respiratory and Critical Care Medicine, 2003 International Conference, The American Thoracic Society, Seattle, WA, May 16-21, 2003