Effects of dietary fiber and inositol hexaphosphate on the onset of carcinoma of large intestine in rats induced by 1,2-dimethylhydrazine / 中国组织工程研究

ABSTRACT

BACKGROUND: Incidence rate of carcinoma of large intestine increases with the development of national living standard. Many epidemiologic surveys have showed that dietary factors have closely correlation with high risk of carcinoma of large intestine.OBJECTIVE: To observe the effect of dietary fiber and inositol hexaphosphate on the incidence of carcinoma of large intestine by establishing rat models with carcinoma of large intestine.DESIGN: Randomized block design.SETTING: Institute of Nutriology, Medical College, Qingdao University.MATERIALS: The experiment was performed at the Institute of Nutriology, Medical College, Qingdao University from March to December 2004.Totally 86 male Wistar rats of 4 weeks were randomly assigned based on body mass into cellulose group with 14 rats, pectin group with 14 rats, inositol hexaphosphate group with 15 rats, cellulose plus inositol hexaphosphate group with 14 rats, pectin plus inositol hexaphosphate group with 14rats and control group with 15 rats.METHODS: Basic feed without dietary fiber was given in the control group. 10% pectin was added in the pectin group. 10% cellulose was added in the cellulose group. 2% sodium phytate was added in the water of inositol hexaphosphate group. 10% pectin and 2% sodium phytate were added in the water of pectin plus inositol hexaphosphate group. 10% cellulose and 2% sodium phytate drinking water were added in the cellulose plus inositol hexaphosphate group. A total of 86 rats received 1,2-dimethylhydrazine (DMH) by subcutaneous injection to induce carcinoma of large intestine at week 4 after breeding. Incidence rate of large bowel neoplasm,number and volume of tumor were observed. Proliferating activity of large intestinal mucosa cells was determined (the ratio of number of positive cells of proliferating cell nuclear antigen to total count of nucleus).MAIN OUTCOME MEASURES: ①Incidence rate of large bowel neoplasm in each group, changes of mean number and mean volume of tumors of each rat, and ②proliferating activity of large intestinal mucosa cells of rats.RESULTS: ①Most of the rats in each group died during the 20-week trial. Oue rat died in the pectin group, the pectin plus inositol hexaphosphate group and the control group, respectively after 20 weeks. ②There was no significant difference in the incidence rate of large bowel neoplasm of rats compared with the control group (P ＞ 0.05), but the mean number and mean volume of tumors of each rat in the inositol hexaphosphate group were significantly lower than those in the control group [quantity: (1.1±0.2),(4.1±1.2)rats,P ＜ 0.01 ;volume: (176.1±65.5), (1 046.7±469.0)mm3,P ＜ 0.05], and the mean number of tumors of each rat in the pectin plus inositol hexaphosphate group was obviously higher than that in the control group [(7.5±1.9), (7.2±1.0) rats,P ＜ 0.05]. ③The proliferating activity of large intestinal mucosa cells in the inositol hexaphosphate group significantly decreased as compared with the control group. The proliferating activity of large intestinal mucosa cells in the pectin group increased as compared with the control group [(41.8±4.7)%, (83.6±2.9)%,(66.7±7.8)% ,P ＜ 0.01 and 0.05].CONCLUSION: It may increase the incidence rate of carcinoma of large intestine when pectin is added in diet, on the contrary, the rate decreases if inositol hexaphophate is added in the water.