Research Report
Copyright ©2014 Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jun 7, 2014; 20(21): 6541-6546
Published online Jun 7, 2014. doi: 10.3748/wjg.v20.i21.6541
Effects of bile acids on cyclooxygenase-2 expression in a rat model of duodenoesophageal anastomosis
Naoki Hashimoto
Naoki Hashimoto, Department of Surgery, Kinki University, Osaka 589-8511, Japan
Author contributions: Hashimoto N solely contributed to this paper.
Correspondence to: Naoki Hashimoto, MD, PhD, Department of Surgery, Kinki University, 377-2 Ohonohigashi, Osakasayama, Osaka 589-8511, Japan. gojigen000@gmail.com
Telephone: +81-723-660221 Fax: +81-723-683382
Received: October 11, 2013
Revised: February 28, 2014
Accepted: March 12, 2014
Published online: June 7, 2014
Abstract

AIM: To examine the expression of cyclooxygenase-2 (COX-2) and prostaglandin E2 (PGE2) in rat esophageal lesions induced by reflux of duodenal contents.

METHODS: Thirty 8-week-old male Wistar rats were exposed to duodenal content esophageal reflux. All animals underwent an esophagoduodenal anastomosis (EDA) with total gastrectomy to elicit chronic esophagitis. In ten rats sham operations with only a midline laparotomy were performed (Control). The rats were sacrificed at the 40th week, their esophagi were taken for hematoxylin and eosin staining and for examination of expression of COX2, PGE2, and proliferating cell nuclear antigen (PCNA), and total bile acids in the esophageal lumen was measured.

RESULTS: After 40 wk of reflux, columnar dysplasia, squamous cell carcinoma and adenocarcinoma were observed. Total bile acids in the esophageal lumen were significantly increased in the EDA group compared with the sham operated rats. PCNA labelling index and esophageal tissue PGE2 levels were higher in dysplastic and cancer tissues than in control tissues. Overexpression of COX2 was observed in dysplastic and cancer tissues.

CONCLUSION: Reflux of duodenal contents induces COX2 expression and increases prostaglandin synthesis in dysplastic and cancer tissues. This result suggests a possible mechanism by which bile acids promote esophageal cancer.

Keywords: Bile acids, Cyclooxygenase-2, Prostaglandin E2, Esophageal cancer, Esophagoduodenal anastomosis

Core tip: It is known that reflux of duodenal contents (bile acids) can induce mucosal injury, stimulate cell proliferation, and promote tumorigenesis. We examined the expression of cyclooxygenase-2 (COX-2) and prostaglandin E2 in rat esophageal lesions induced by reflux of duodenal contents. All animals underwent an esophagoduodenal anastomosis with total gastrectomy to elicit chronic esophagitis. We demonstrated that reflux of duodenal contents induces COX-2 and increases prostaglandin synthesis in dysplastic and cancer tissues. This result suggests a possible mechanism by which bile acids promote esophageal cancer.