Nuclear factor-κB inhibition by pyrrolidinedithiocarbamate attenuates gastric ischemia-reperfusion injury in rats

Abstract

Pyrrolidinedithiocarbamate (PDTC) is a potent antioxidant and an inhibitor of nuclear factor-κB (NF-κB). The present study examined the impact of PDTC preconditioning on gastric protection in response to ischemia-reperfusion (I/R) injury to the rat stomach. Male Wistar rats were recruited and divided into 3 groups (n=7). One group was subjected to gastric ischemia for 30 min and reperfusion for 1 hour. The second group of rats was preconditioned with PDTC (200 mg/kg body mass i.v.) 15 min prior to ischemia and before reperfusion. The third group of rats was sham-operated and served as the control group. Gastric I/R injury increased serum lactate dehydrogenase level, vascular permeability of gastric mucosa (as indicated by Evans blue dye extravasation) and gastric content of inflammatory cytokine; tumor necrosis factor-α (TNF-α). Moreover, oxidative stress was increased as indicated by elevated lipid peroxides formation (measured as thiobarbituric acid reactive substances) and depleted reduced glutathione in gastric tissues. NF-κB translocation was also detected by electrophoretic mobility shift assay. Microscopically, gastric tissues subjected to I/R injury showed ulceration, hemorrhages, and neutrophil infiltration. Immunohistochemical studies of gastric sections revealed increased expression of p53 and Bcl-2 proteins. PDTC pretreatment reduced Evans blue extravasation, serum lactate dehydrogenase levels, gastric TNF-α levels, and thiobarbituric acid reactive substances content, and increased gastric glutathione content. Moreover, PDTC pretreatment abolished p53 expression and inhibited NF-κB translocation. Finally, histopathological changes were nearly restored by PDTC pretreatment. These results clearly demonstrate that NF-κB activation and pro-apoptotic protein p53 induction are involved in gastric I/R injury. PDTC protects against gastric I/R injury by an antioxidant, NF-κB inhibition, and by reduction of pro-apoptotic protein p53 expression, which seems to be downstream to NF-κB, thus promoting cell survival. Key words: pyrrolidinedithiocarbamate, ischemia–reperfusion injury, gastric mucosa, nuclear factor-κB, inflammatory cytokines, oxidative stress.