Pathological changes of lung tissue and oxidative stress in rats exposed to welding fumes

Abstract Welding fumes are ‘possibly carcinogenic’ according to the International Agency for Research on Cancer (IARC) and may have negative health impacts on workers who inhale them. This study examines the differences in lung tissue pathology and oxidative stress levels between rats exposed to welding fumes and a control group. Shielded metal arc welding fumes with a concentration of 50 mg/m3 were inhaled by male Wistar rats (n = 6/treatment group) for 30 min/day × 8 days. The control group (n = 6) was maintained in normal laboratory air condition. Gravimetry was used to measure the particle size distribution, which showed that most particles were in the micron range with a significant number of ≥ 0.25-sized particles. The chemical composition of the fumes was sampled for heavy metals following the National Institute for Occupational Safety and Health (NIOSH) method 7300 and analyzed by inductively coupled plasma mass spectroscopy (ICP-OES). The results showed that rats exposed to welding fumes had significant changes in SOD and GPx activity compared to the control group. The mean activity of GPx in the control and experiment groups was 16.34380 (mU/mg protein) and 11.81042 (mU/mg protein), respectively. The mean activity of SOD in the control and experiment groups was 275.587 (U/mg protein) and 121.168 (U/mg protein). The lung tissues of the control rats were normal, while the exposed rats showed mild to severe tissue injuries in the bronchial and alveolar spaces and the alveolar septa.