COMPARISON OF RESISTANT STARCH WITH CELLULOSE DIET ON 1,2-DIMETHYLHYDRAZINE-INDUCCED COLONIC CARCINOGENESIS IN RATS

流行病学和实验研究表明，膳食纤维可以预防结肠癌。抗性淀粉，像食素纤维一样，在小肠中不容易被消化。然而，抗性淀粉是否能抑制结肠癌的发生尚不清楚。体外研究表明，丁酸盐能促进培养的结肠癌细胞的生长。研究了抗性淀粉饮食对1,2-二甲基肼诱导大鼠结肠癌的影响，并测定了结肠丁酸盐浓度。将sd - dawlet大鼠随机分为5组，分别饲喂不含纤维、30%纤维素、10%纤维素、3%抗性淀粉和10%抗性淀粉的饲粮。比较各组结肠内容物和粪便中丁酸盐浓度及结肠癌变情况。10%纤维素组每只大鼠总癌体积显著低于基础组（109 54 mm^3和147 83mm^3， p<0.05），其余各组差异不显著。抗性淀粉组结肠内容物和粪便中丁酸盐浓度均高于纤维素组。抗性淀粉增加了丁酸盐浓度，但对其结肠癌变没有抑制作用。丁酸盐是否能抑制结肠癌细胞的增殖尚存疑问。

Epidemiological and experimental studies have shown that dietary fiber may prevent colon cancer. Resistant starch, like kietary fiber, is not subject to digestion in the small intestine. However, it is unknown whether resistant starch inhibits colonic carcinogenesis. In vitro studies have shown that butyrate shows the growth of cultured colon cancer cells. The effect of resistant starch diet on 1,2-dimethy l hydrazine-induced colonic carcinogenesis in rats was evaluated, and the colonic butyrate concentration was measured. Sprague-Dawlet rats were randomly divided into five groups that were fed diets containing no fiber, 30% cellulose, 10% cellulose, 3% resistant starch, or 10% resistant starch. Colonic carcinogenesis and butyrate concentration of colonic contents and feces in each diet group were compared.Total cancer volume per rat in the 10% cellulose group was significantly lower than that in the basal group (109 54 mm^3 and 147 83mm^3 ; p<0.05), but the other groups showed no significant differences. The butyrate concentration in colonic content and in feces were higher in the resistant starch group than in the cellulose group. The resistant starch siet increased butyrate concentration but did not inhib it colonic carcinogenesis. It remains doubtful wether butyrate inhibits the proliferation of colon cancer cells.