downregulation of super oxide dismutase level in protein might be due to sulfur mustard induced toxicity in lung.

sulfur mustard (sm) has been identified as an important chemical weapon. during the iran-iraq war of 1980-88, the extensive usage of sm against iranian civilians and military forces was proven. this agent has been shown to cause severe damage mainly in the skin, eyes, lungs,  and  respiratory  tract  in  iranian  veterans.  the  most  common  disease  is bronchiolitis obliterans (bo)). sm increases the endogenous production of reactive oxygen species (ros). superoxide dismutases (sods) are known as protective antioxidants against the harmful effects of ros. twenty exposed sm individuals (43.2±6.4 years), and 10 normal controls (41.3±2.5 years) were enrolled in this study. evaluation of sods was performed by semiquantitative rt-pcr and mmunohistochemistry. our  results  demonstrated  that  cuznsod   and  mnsod  mrna  were  up-regulated 2.79±1.09  and  2.49±1.11  folds, respectively in sm-injured patients  in comparison  with control  levels. in  contrast,  immunohistochemistry  results  showed  downregulation  of cuznsod protein expression in sm injured patients. our results revealed that sods may play an important role in cellular protection against oxidative stress due to mustard gas toxicity in airway wall of sm exposed patients.