Protective effect of leptin against ischemia-reperfusion injury in the rat small intestine

The small intestine is extremely sensitive to ischemia-reperfusion (I/R) injury and a range of microcirculatory disturbances which contribute to tissue damage. Previous studies have shown that leptin plays an important physiological role in the microvasculature. The aim of this study was to evaluate the protective effects of leptin in I/R--induced mucosal injury in the small intestine.

Forty rats were divided into 5 groups (n = 8). Group I was subjected to a sham operation. Following mesenteric ischemia in group II (control); physiologic saline 1 cm3, in group III; leptin 100 microg/kg, and physiologic saline 1 cm3, in group IV; NG-L-arginine methyl ester (L-NAME) 20 mg/kg, and physiologic saline 1 cm3, in group V; leptin 100 microg/kg, L-NAME 20 mg/kg, and physiologic saline 1 cm3 were given intra-peritoneally. In these groups, an I/R procedure was performed by occlusion of the superior mesenteric artery for 45 min followed by 120 min reperfusion. After reperfusion, the small intestines were resected for malondialdehyde (MDA) and nitric oxide (NO) concentration and histopathologic properties. Mucosal lesions were scored between 0 and 5. Tissue MDA and NO concentration and histopathologic grades were compared statistically.

Tissue MDA level significantly increased (P < 0.05), tissue NO level significantly decreased in group V animals, compared to group III animals respectively (P < 0.001). Histopathologically, intestinal injury significantly decreased in the leptin treated ischemic group.

Leptin can be used safely in mesenteric occlusive diseases, since it induces NO formation and release in mesenteric vessels.