The Study of Histopathological Effects of Electric Welding Fumes on Bronchiole and Lung of Rats

Purpose: The aim of the present study was to identify the quantitative and qualitative changes of bronchiole and lung alveoli in Rat after exposure to welding fumes. Materials and Methods: A total number of 60 male Sprague Dawley Rats were divided into two groups: imental (40) and control (20). Rats of each group were subdivided into 2, 4, 6 and 8 subgroups. Experimental Rats were exposed to welding fumes for 2 hour/day and 5day/week in exposure chamber. According to timetable lung samples were taken from all groups and processed routinely, sections from paraffin blocks were stained by H-E, PAS, Van Gaisson, Alcian Blue pH=2.5 and PNA & WGA lectins. Epithelial thickness of bronchiole was measured after calibration of microscope and data were analyzed by Kruskall Wallis test. The amount of gases and particles measured in exposure chamber. Results: The results of the study showed the disorganized architecture and polarity of epithelial cells with nuclear hypercromasia in bronchioles and alveoli. The nature of secretary products of goblet cells was changed in experimental group. The increase in the amount of collagen fiber showed the fibrotic changes of lung. Kruskall Wallis test showed significant changes for epithelial thickness between control and experimental groups in 4 and 8 weeks (p<0.02). Conclusion: It seems that the bronchiole and alveoli responses to welding fumes follow an adaptive and reactive process. The severity of these responses is well correlated with the duration of exposure to welding fumes.