effect of red grape seed extract on the experimental model of ulcerative colitis in male albino rats: a histological, immunohistochemical and biochemical study

ABSTRACT

Ulcerative colitis [UC] is a chronic inflammatory disorder of the large bowel. Red grape seed extract [GSE] has antioxidative, anti-inflammatory and antimicrobial activities. This study was designed to evaluate the protective properties of GSE on an animal model of acetic acid-induced UC. Rats were divided into three groups group I - the control group; group II - the UC group in which UC was induced by a single intracolonic injection of 2 ml of 3% acetic acid; and group III - the GSE-treated group in which rats were administered GSE at 400 mg/kg/day, orally for 4 days, after induction of UC. Colon sections were subjected to H and E, and immunohistochemical staining of vascular endothelial growth factor [VEGF] and alpha-smooth muscle actin [alpha-SMA]. Tumour necrosis factor-alpha [TNF-alpha], interleukin [IL]-6 and IL-10 were determined in blood by enzyme-linked immunosorbent assay. The UC group showed patchy mucosal ulceration, mononuclear cell infiltration extending to the muscularis externa, increased blood vessels in the mucosa and wide separation of muscle fibers in the muscularis externa. UC significantly increased the plasma levels of proinflammatory cytokines TNF-alpha and IL-6 and significantly decreased immunoregulatory cytokine IL-10 level in plasma. On histologic assessment it was observed that GSE protected the colon from acetic acid-induced UC by preserving colonic crypts and their lining epithelium while decreasing mononuclear cell infiltration. This histological improvement was associated with a significant decrease in the plasma levels of TNF-alpha and IL-6 and a significant increase in plasma IL-10 level. Moreover, GSE significantly decreased the VEGF and alpha-SMA immunostaining in colonic tissues as compared with the UC group. This study proved the protective effect of GSE in experimentally induced UC in rats