P011. The impact of omentectomy on the severity of colitis and adipocytokine expression
S. Yapali1, N. Oruc1, C. Yenisey2, M. Sezak3,4, N.G. Ceri5, O. Ozutemiz1, 1Ege University, School of Medicine, Gastroenterology, Izmir, Turkey, 2Adnan Menderes University, School of Medicine, Biochemistry, Aydin, Turkey, 3Ege Universit, School of Medicine, Pathology, Izmir, Turkey, 4Ege University, School of Medicine, Pathology, Izmir, Turkey, 5Adnan Menderes University, School of Medicine, Anatomy, Aydin, Turkey
Regarding the unidentified role of omental adipose tissue on intestinal inflammation, we hypothesized that complete removal of omentum may alter the severity of intestinal inflammation by changing cytokine and adipokine expression. We aimed to determine whether removal of omentum has any impact on the severity of colitis and the expression of cytokines and adipokines in an experimental model of trinitrobenzene sulphonic acid (TNBS) colitis induced after 6 months following omentectomy.
Forty Wistar albino rats (20 M, 20 F) were divided into two groups. Group A (n = 20) underwent laparotomy and Group B (n = 20) underwent sham laparatomy without omentectomy. After 6 months following omentectomy, induction of colitis was performed by a single intracolonic administration of 0.25ml of 30% ethanol (V/V) containing 30 mg of 2,4,6-TNBS. Control groups received 0.25 ml of vehicle (30% ethanol) with a similar method. Rats were divided into four groups: 1. Omentectomy & TNBS colitis; 2. Sham operated & TNBS colitis; 3. Omentectomy & ethanol; 4. Sham operated & ethanol. Distal colon and mesenteric fat tissue were removed for histological and biochemical assessments. Myeloperoxidase (MPO) activity, tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-18, were determined in colonic tissue homogenates by enzyme-linked immune sorbent assay (ELISA). Leptin and adiponectin levels were determined both in colonic and mesenteric fat tissue homogenates by ELISA. Expression of adipocytokines and severity of colitis were compared between the groups.
Macroscopic and histologic scoring of colitis tended to be higher in rats who underwent omentectomy and administered TNBS, the severity of colitis and MPO levels were not significantly altered with omentectomy. TNF-alpha (p = 0.006), IL-18 (p = 0.002) and adiponectin (p = 0.004) levels were significantly higher in Group 1 than those in Group 2. Omentectomy did not alter colonic leptin levels significantly. Moreover, mesenteric adipocytokine levels did not change significantly between the groups.
Omentectomy led to significantly increased TNF-alpha, IL-18 and adiponectin levels that was accompanied by an increased tendency of colonic damage. The effects of increased cytokines on microscopic and histological findings may be a subsequent event. Removal of omental adipose tissue might also enhance dysregulation of mesenteric adipocytokine expression. This is the first study investigating long-term effects of omentectomy in an experimental model of colitis and demonstrating that omentum keeps the novel protective role in intestinal inflammation.