Smad molecules expression pattern in human bronchial airway induced by sulfur mustard

Airway remodelling is characterized by the thickening and reorganization of the airways seen in mustard lung patients. Mustard lung is the general description for the chronic obstructive pulmonary disease induced by sulfur mustard(SM). Pulmonary disease was diagnosed as the most important disorder in individuals that had been exposed to sulfur mustard. Sulfur mustard is a chemical warfare agent developed during Wars. Iraqi forces frequently used it against Iranian during Iran -Iraq in the 1980-1988. Peribronchial fibrosis result from airway remodeling that include excess of collagen of extracellular matrix deposition in the airway wall. Some of Smads families in association with TGF-β are involved in airway remodeling due to lung fibrosis. In the present study we compared the mRNA expression of Smad2, Smad3, and Smad4 and Smad7 genes in airway wall biopsies of chemical-injured patients with non-injured patients as control. We used airway wall biopsies of ten unexposed patients and fifteen SM-induced patients. Smads expression was evaluated by RT-PCR followed by bands densitometry. Expression levels of Smad3 and Smad4 in SM exposed patients were upregulated but Smad2 and Smad7 was not significantly altered. Our results revealed that Smad3, and 4 may be involved in airway remodeling process in SM induced patients by activation of TGF-β. Smad pathway is the most represented signaling mechanism for airway remodeling and peribronchial fibrosis. The complex of Smads in the nucleus affects a series of genes that results in peribronchial fibrosis in SM-induced patients.