Protective Effects of L‐Arginine on Rat Terminal Ileum Subjected to Ischemia/Reperfusion

ABSTRACT 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 NG‐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.