Protective effect of erythropoietin on histological, immunohistochemical and biochemical changes of ileal mucosa induced by intestinal ischemia/ reperfusion injury in adult albino rat

ABSTRACT

Erythropoietin [EPO] is a hypoxia-induced cytokine. It is traditionally known to regulate erythropoiesis, but recently its protective effect against Ischemia/Reperfusion injury [I/R] has been studied in cardiovascular and neuronal systems and other tissues. This work was carried out to demonstrate the possible protective role of erythropoietin in ameliorating the effect of experimentally induced intestinal ischemia/reperfusion injury histologically, immunohistochemically and biochemically. Fifty adult albino rats were divided into three groups Group I [Control Group]; Group II [Ischemia/Reperfusion] and group III [ischemia/reperfusion with erythropoietin]. The superior mesenteric artery was occluded for 60-min to induce ischemia and then the clamp was removed for 120-min for reperfusion. EPO [5000 U/ kg] was administered intraperitoneally at the onset of reperfusion. At the end of the reperfusion period terminal ileum was extracted for histological examination and immunohistochemical detection of the distribution of proliferating cell nuclear antigen [PCNA] from all animals. The levels of malondialdehyde [MDA, a biomarker of oxidative damage], myeloperoxidase [MPO, an index of the degree of neutrophil accumulation] and glutathione [GSH, a biomarker of protective oxidative injury] were also determined in all dissected tissues. In the Ischemia/Reperfusion [I/R] group, the mucosa of the ileum showed shortening and distortion of the villi, erosion of the lining epithelium, degeneration of epithelial cells of the villi and the crypts of Leiberkuhn. Inflammatory cellular infiltration in mucosa was also observed. Ultrastructurally, degenerative changes were observed in the enterocytes in the form of cytoplasamic vacuolation, mitochondrial degeneration and dilatation of rER. The levels of MDA and MPO were significantly increased whereas those of GSH were significantly decreased. Immunohistochemical study revealed a non significant increase in the number of PCNA - positive nuclei in the crypts. On the other hand, when erythropoietin was administrated at the onset of reperfusion [Group III], intestinal morphological changes were alleviated and the levels of MDA and MPO were significantly decreased whereas those of GSH were significantly increased. Immunohistochemical study revealed a significant increase in the PCNA positive nuclei in the crypts of Leiberkuhn. EPO exerts a protective effect against intestinal I/R injury in rats by reducing oxidative stress and promoting enterocytes proliferation. Therefore, erythropoietin may offer a new protective strategy for I/R injury in the field of intestinal surgery and transplantation