Protective effects of L-arginine on rat terminal ileum subjected to ischemia/reperfusion

OBJECTIVES: Studies have shown that nitric oxide (NO) may play a major role in sustaining mucosal integrity; however, NO has been also implicated in the pathogenesis of ischemia/reperfusion (I/R)-related tissue injury. We investigated the effects of L-arginine and N-nitro L-arginine methyl ester (L-NAME) on the acetylcholine-induced contractile response of ileum and the levels of malondialdehyde (MDA) and reduced glutathione (GSH). Histopathological changes were also evaluated in ileal preparations. MATERIALS AND METHODS: Male Wistar Albino rats were subjected to mesenteric ischemia (30 min) followed by reperfusion (3 hours). Four groups were designed: sham-operated control; I/R; I/R and L-arginine pretreatment; and I/R and L-NAME pretreatment. After reperfusion, ileum specimens were collected to determine the parameters mentioned above. RESULTS: Following reperfusion, a significant decrease in acetylcholine-induced contractile response, an increase in lipid peroxidation, a decrease in GSH content, and mucosal damage of the ileal preparations were observed. We showed that decreased contractility, increased lipid peroxidation, and reduced GSH content have been reversed by L-arginine but not by L-NAME. Mucosal injury was significantly lowered in the L-arginine group. CONCLUSIONS: Treatment with L-arginine exerted a protective effect in intestinal I/R injury, which was mediated in part by regulating MDA and GSH levels, consequently ameliorating impaired contractile response and mucosal injury. © 2008 Lippincott Williams & Wilkins, Inc