The Influence Of Dietary Fiber And Inositol Hexaphosphate On 1, 2-Dimethylhydrazine Induced Colon Carcinogenesis

Objective In this study, we evaluated the effect of dietary fiber (DF) and inositol hexaphosphate (IP6 or Insp6) on 1, 2-dimethylhydrazine (DMH) induced colon carcino-genesis in Wistar rats and discussed the mechanism underlying the anti-neoplastic potential of them.Methods 90 four-week-old male Wistar rats were divided randomly into 6 groups of 15 rats each ( Pectin-group B,Cellulose-group C,InsP6-group D, Pectin+InsP6-group E, Cellulose+InsP6-group F, Control group-group A) . Four weeks following the beginning of their special diets, the rats were given a weekly injection of DMH (20mg/kg) for 20 weeks. The rats were killed after 26 weeks. The number of total macroscopically visible neoplasms was counted and the volume of individual neoplasmas was calculated. Proliferation cell nuclear antigen (PCNA) and SOD, GSH-Px and MDA of colon were analyzed as well as Natural killer cell activity.Results (2)Compared to control group, the mortality of rats of group D decreased significantly (P<0. 01) and there was no significant differences in other groups. (2)The inci-dence of tumors in Wistar rats of group D was a little lower than group A , but it was no significance , and there was no significant differences in other groups . However group D significantly reduced the number of tumors per rats(P<0. 01 )and tumor volume(P< 0. 05). Group B and group E enhanced the number of tumors per rats (P<0. 05) but group C and group F had no significant effect. Tumor volume per rats of group F was significantly lower (P<0. 05) but in group B, group C and group E significantly higher(P<0. 01) , especially in group B than in group A. (3)The expression of proliferation marker PCNA was significantly down-regulated by InsP6(P<0. 05) but up-regulated by Pectin(P< 0. 05), and there was no significance in other groups. (4)Group D significantly raised SOD and GSH-Px activity of colon and reduced MDA content (P<0. 01), but group B significantly decreased SOD and GSH-Px activity of colon and enhanced MDA content (P < 0.05),and there was no significance in other groups. (5)Group D significantly enhanced NK activity (P<0. 01) and group B significantly reduced NK activity (P<0. 05), while there was no significance in other groups.Conclusion Cellulose and Pectin we used in this study was ineffective in significantly reducing the risk of large intestinal cancer in Wistar rats while InsP6 was effective in significantly reducing the risk. We postulate that InsP6 may exert its antineoplastic effect by the way of its antioxidant function and lowering cellular proliferation as well as enhancing the NK cell activity and inhibiting the apoptosis of large intestinal cancer cells. The con-bined effect of Inp6 and pectin or cellulose was no significance.