Pulmonary Function Changes in Sprague Dawley Rats

Welder’s pneumoconiosis has generally been determined as benign based on the absence of pulmonary function abnormalities in welders with marked radiographic abnormalities. Yet, there have also been several reports on welders with respiratory symptoms, indicating lung function impairment, X-ray abnormalities, and extensive fibrosis. Accordingly, this study attempted to investigate the inflammatory responses and pulmonary function changes in rats during a 60-day welding-fume-inhalation exposure period to elucidate the process of fibrosis. The rats were exposed to manual metal-arc stainless-steel welding fumes (MMA-SS) with total sus-pended particulate concentrations of 64.8 6 0.9 (low dose) and 107.86 2.6 mg/m3 (high dose) for 2 h per day in an inhalation chamber for60 days. Animals were sacrificed after the initial 2-h exposure and after 15, 30, and 60 days, and the pulmonary function was also measured every week after the daily exposure. Elevated cellular differentia