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.