Effects of high-fiber diets on pathological changes in DMH-induced rat colon cancer.
The protective role of dietary fibers on tumorigenic effects of 1,2-dimethylhydrazine (DMH) on the rat colon was studied using histochemical, immunohistochemical, and biochemical analyses. Rats were injected with DMH (20 mg/kg sc) for five weeks, once a week, and were fed laboratory chow (Control I), semisynthetic fiber-free diet (Control II), or 18% or 25% assorted fiber (cellulose, beans, corn) diet. The rats were sacrificed 12, 16, and 24 weeks after the carcinogenic injections. Adenomatous tumors developed in 90-100% of the animals fed chow or fiber-free diets. A diet with high concentrations (25%) of corn dietary fiber significantly decreased the tumor incidence (40% and 42%) and tumor yield (p < 0.01). Diets with lower concentrations of fibers (18%) did not protect against tumorigenic effects of DMH. No differences were found in pathological parameters of tumors obtained from different dietary groups: the damage index (percentage of damaged cells per section) was very similar in all groups studied. Diets enriched with dietary fibers (25%) had a significant protective effect in DMH-induced rat colon cancer.
Madar
Z
Z
School of Nutritional Sciences, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot, Israel.
Timar
B
B
Nyska
A
A
Zusman
I
I
D019813:1,2-Dimethylhydrazine; D000818:Animals; D002273:Carcinogens; D003110:Colonic Neoplasms / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D004043:Dietary Fiber; D004127:Dimethylhydrazines; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
D002273:Carcinogens; D004043:Dietary Fiber; D004127:Dimethylhydrazines; D019813:1,2-Dimethylhydrazine