2026-11-092026-11-09https://scholars.csmu.edu.tw/handle/123456789/38077The role of nondigestible carbohydrates, including the nondigestible oligosaccharides and dietary fiber, in prevention of colon cancer is diverse and inconclusive. Therefore, the aim of this study is to explore the modulatory effects of konjac glucomannan, inulin, and short-chain oligofructose on the biomarkers of colon cancer, such as the proliferative indices of colonic mucosa, bowel function, fecal microflora, fecal bile acid and short chain fatty acid (SCFA). In addition, the genotoxicity of fecal water from mice fed these fiber sources will also be examined. Eight-wk-old male Balb/c mice (n=20 per group) will be randomly allocated to consume one of three modified AIN-93 diets, each containing 5% of cellulose, konjac, inulin or oligofructose, for 21 days. Animals will be cared according to the guideline. Feces will be collected during days 18-21 when mice are placed in metabolic cages. We will determine the SCFA and microflora including total anaerobes, bifidobacteria, lactobacilli, Clostridium perfringens, and E. coli, in feces. The fecal water obtained after ultracentrifugation will be prepared to determine the primary and secondary bile acids, and its genotoxicity on Caco-2 cells. In addition, the cecum and distal colon will be processed to determine the proliferative indices of epithelial cells. The results of this study will explore the role of these nondigestible carbohydrates on the occurrence of colon cancer.根據衛生署資料顯示，直結腸癌為國人癌症死亡原因中排名第三，因此值得我們針對直結腸癌之預防做深入之研究。在一些流行病學的研究中發現，膳食纖維的攝取是預防人類大腸癌的重要因子之一，但是難消化寡醣在預防人類大腸癌之作用不明。難消化碳水化合物(膳食纖維及難消化寡醣之總稱)種類繁多而複雜，其醣基聚合度、鍵結方式、水溶性、黏稠度等都是影響其生理功能之因素。根據動物實驗得知不可溶性膳食纖維(如纖維素)有預防直結腸癌之作用，但是可溶性難消化碳水化合物對預防直結腸癌之作用卻相當分歧，而且目前研究之種類侷限於西方飲食常見之果膠、關華膠等，未能有效探討國人常食用之可溶性難消化碳水化合物對預防直結腸癌發生之效果。因此本研究提案將比較不可溶之纖維素及三種可溶性難消化碳水化合物(長鏈蒟蒻葡甘聚醣纖維、中鏈菊糖及短鏈果寡糖)對大腸癌之預測生物指標(如黏膜細胞增生及糞便成分對黏膜細胞產生之毒性)的調控作用，以及一些可能的影響因子(如腸道菌相、排便特性、腸道內容物短鏈脂肪酸及膽酸濃度等)。將八週齡BALB/c雄鼠每組20隻，隨機分配於以下各組：AIN-93無纖維半純化飼料(無纖維組)，以及AIN-93飼料中分別以纖維素、蒟蒻精粉、菊糖、和果寡糖作為纖維來源等5組， 21天後犧牲小鼠。小鼠於自動照光控制系統 ( 12小時日夜循環 )，室溫均保持在25±1℃，相對濕度55±5% 的環境下飼養。餵食期間採自由進食，每週測量體重二次，每日記錄進食狀況。犧牲前三天(第18-20天)連續收集72小時糞便，以便測定各難消化碳水化合物對糞便短鏈脂肪酸，糞便總驗氧菌、雙歧桿菌、乳酸桿菌、產氣莢膜梭菌、大腸桿菌菌數及糞便水液中一級及二級膽酸濃度之影響。此外，製備糞便水後，於體外測定各難消化碳水化合物降低糞便水對人類大腸腺癌細胞株(clone of Caco-2, ATCC 60182)之毒性作用。實驗第21天，以斷頭法犧牲小鼠，收集盲腸內容物以測定盲腸內容物短鏈脂肪酸濃度，並收集盲腸及末端結腸組織以分析各難消化碳水化合物對大腸黏膜細胞的增生作用。相信此研究結果有助於釐清蒟蒻精粉、菊糖、和果寡糖對直結腸癌發生之影響，以作為防癌飲食設計之科學依據。難消化碳水化合物大腸癌膽酸基因毒性nondigestible saccharidescolon cancerbile acidgenotoxicityProject