Expression of glutathione S-transferase variants in human airway wall after long-term response to sulfur mustard

Abstract

Context: Sulfur mustard (SM) is an alkylating agent identified as a potent chemical warfare agent. More recently, SM was used in the Iraq conflict against Iranian troops and civilians. At present, there are many people suffering from chronic obstructive pulmonary disease (COPD) due to mustard gas in Iran. SM increases the endogenous production of reactive oxygen species (ROS). The oxidant/antioxidant imbalance present in the lungs of these patients also results from the impaired capacity of the antioxidant/detoxification enzymes to detoxify the harmful reactive oxygen metabolites. Objective: One of the major antioxidants in human airways is glutathione S-transferase. They facilitate the detoxification of various environmental of oxidative stress. In this study, we attempted to understand the significance different in expression of GSTs in airway wall of chemical patients and control. Materials and methods: Seven normal and 20 SM induced COPD individuals were studied. Bronchoscopy was performed in all subjects and two specimens were taken from the main bronchus for mRNA extraction, PCR analysis and immunohistochemistry. Results: SM-induced COPD individuals showed expression of GSTA1 2.51 ± 0.83-, GSTM1 2.84 ± 1.71- and GSTP1 5.61 ± 2.59-folds higher than those of controls that revealed. GSTP1-immunoreactivity was strongly expressed in luminal border of normal samples. SM patient samples immunoreactivity for GSTP1 in the same area were negative. Discussion and conclusion: According to these findings, we speculated that overexpression of GSTs mRNA in patients revealed that GSTs plays an important role in cellular protection against oxidative stress of MS in airway wall of patients.