Identification of nitrated proteins that may play a critical role in the pathogenesis of methotrexate induced small intestinal damage in the rat and possible ways to prevent the damage by the administration of nitric oxide synthase inhibitor

Abstract

The ultimate purpose of the study was to identify the modifications and consequence due to nitrosative stress by which MTX causes small intestinal damage. Increased nitric oxide production was found to be associated with gut barrier failure and inflammation. In the first study, we have assessed the role the nitrosative stress in MTX induced small intestinal damage by measuring the nitrosative stress parameters in the small intestine samples at 24 hours after 3 consecutive intraperitoneal injections of MTX at the dose of 7 mg / kg body weight. Nitric oxide level (Nitrite + Nitrate), expression of inducible nitric oxide synthase and nitrotyrosine was increased in MTX treated samples. newlineThe study was designed to investigate the roles of peroxynitrite (PON) induced protein tyrosine nitration, NFkappaB-iNOS-COX-TNFand#61537; signaling pathway and apoptotic pathway in methotrexate induced small intestinal damage and to evaluate the efficacy of aminoguanidine, a selective iNOS inhibitor in the prevention of the damage using rat model. newlineWe also assessed peroxynitrite induced protein tyrosine nitration, subcellular distribution on nitrated proteins to identify the proteins that may undergo nitration. We found many proteins either increase or decrease expression of nitrotyrosine modification in the cell fractions including homogenate, nucleus, mitochondria, microsomes and cytosol. Thus, it is concluded that there is strong association of nitrosative stress that lead to nitration of proteins to the extent of major subcellular fractions may play a role in MTX induced mucositis. newlineIn conclusion, AG pretreatment improved MTX induced morphological changes in the small intestine inhibited the NFand#954;B inflammatory pathway and apoptotic pathway. Thus, aminoguanidine has a protective role in MTX induced mucositis. newlineIt is therefore concluded that aminoguanidine appeared to be potential agent that reduce MTX induced small intestinal damage. newline newline