A preliminary study on development of small intestinal cancer in rats

Abstract

Objective To observe the mucosal structure and aberrant crypt foci (ACF) of small and large bowel in rats induced by DMH and to explore the growth and development of small intestinal tumors. Methods Thirty-four male Wistar rats were randomly divided into two groups: DMH-induced group (25 rats) and control group (9 rats). After 30-32 weeks, these rats were performed with laparotomy, and their small intestine and large intestine were dissected. The mucosa structure and ACF were observed and recorded. The tissues of small intestine and large intestine in control group and the samples of tumor, adjacent normal tissues and ACF tissues in DMH-induced group were subjected to hematoxylin and eosin (H&E) staining and were used to observe histological changes by microscopy. Results The mucosa structure and histological changes of small and large intestine were normal in control group. There were 7 small intestinal tumors and 28 large intestinal tumors in DMH-induced group, respectively. The surface structures of small intestine mucosa and tumor adjacent mucosa were normal. The scattered lymphocytes infiltration was observed in small intestinal mucosa and tissues adjacent to tumor in DMH-induced group, while ACF was observed in large intestinal mucosa and tissues adjacent to tumor in DMH-induced group. Conclusions The occurrence of small intestinal tumors may be induced by some cells directly in the carcinogenesis under the role of the carcinogenic factors in small intestine mucosa with poor tumor differention and high malignancy. The development of small intestinal cancer does not follow the 'ACF-adenoma-adenocarcinoma' model in large intestine. Key words: Intestinal neoplasms; Small intestine; Large intestine; Aberrant crypt foci; Pathology