Young G P, McIntyre A, Albert V, Folino M, Muir J G, Gibson P R
Department of Medicine, University of Melbourne, Royal Melbourne Hospital, Victoria, Australia.
Gastroenterology. 1996 Feb;110(2):508-14. doi: 10.1053/gast.1996.v110.pm8566598.
BACKGROUND & AIMS: Starch that escapes digestion in the small intestine (resistant starch [RS]) may act similarly to nonstarch polysaccharides in the colon. The aim of this study was to examine the effect of raw potato starch alone and in combination with wheat bran on tumor development and precancer events in a rat model of colorectal cancer.
Three groups of rats received either a low-RS/low-fiber ("basic") diet, the basic diet containing raw potato starch as 20% of carbohydrate content, or the potato starch diet plus 10% of "wheat bran" fiber. Epithelial proliferation, aberrant crypt foci (ACF), and tumors were measured 6 and 20 weeks after a 10-week course of dimethylhydrazine.
Rats on the potato starch diet had tumors more frequently and had larger tumors than rats consuming the wheat bran or basic diets. Parallel effects on the density of ACF were found 6 weeks after the carcinogen. Although epithelial proliferation was significantly enhanced by potato starch compared with the basic diet, the addition of wheat bran did not suppress this enhancement.
This type-2 RS enhances epithelial proliferation, ACF density, and tumor formation. The addition of wheat bran to an RS-containing diet suppresses tumorigenesis, acting on events responsible for the formation of ACF but not the events controlling the hyperproliferative phase.
在小肠中未被消化的淀粉（抗性淀粉[RS]）在结肠中的作用可能与非淀粉多糖类似。本研究的目的是在大鼠结直肠癌模型中，研究生马铃薯淀粉单独使用以及与麦麸联合使用对肿瘤发生和癌前事件的影响。
三组大鼠分别接受低抗性淀粉/低纤维（“基础”）饮食、碳水化合物含量20%为生马铃薯淀粉的基础饮食或马铃薯淀粉饮食加10%“麦麸”纤维。在接受10周二甲基肼处理后的6周和20周，测量上皮细胞增殖、异常隐窝灶（ACF）和肿瘤。
与食用麦麸或基础饮食的大鼠相比，食用马铃薯淀粉饮食的大鼠肿瘤发生率更高，肿瘤更大。在致癌物处理6周后，发现对ACF密度有类似影响。虽然与基础饮食相比，马铃薯淀粉显著增强了上皮细胞增殖，但添加麦麸并未抑制这种增强作用。
这种2型抗性淀粉可增强上皮细胞增殖、ACF密度和肿瘤形成。在含抗性淀粉的饮食中添加麦麸可抑制肿瘤发生，作用于负责ACF形成的事件，但不作用于控制过度增殖阶段的事件。
