Prevention of initiation and promotion of colon cancer by dietary fiber and design of highly functional dietary fiber.

本研究的目的是通过电离辐射建立大鼠结肠癌模型，并比较膳食纤维喂养与化学诱导的结肠癌模型对癌症发展的影响。我们首次成功地用电离辐射在大鼠结肠粘膜中形成了癌前病变，即异常隐窝灶（ACF）。与化学诱导ACF相比，辐射诱导ACF的特性频率低，但多样性高。饲喂高发酵性膳食纤维，甜菜纤维，在化学模型中抑制ACF，而不是辐射模型。在化学模型中，一种低发酵性的可溶性纤维可以防止结肠ACF的发展，只是在喂食纤维之前，而不是在致癌物的挑战之后。此外，结肠发酵的产物丁酸使用化学诱导的癌症模型阻止了大鼠结肠中ACF的发展。

The aims of this study were to establish a model of colon cancer by ionizing radiation in rats and to compare the effects of dietary fiber feeding on cancer development with those in a chemically-induced colon cancer model. We first succeed to develop precancerous legion, aberrant crypt foci (ACF), in rat colonic mucosa by ionizing radiation. The properties of radiation-induced ACF were low frequency, but high multiplicity compared with the chemically induced ACF Feeding of a highly fermentable dietary fibers, sugarbeet fiber, suppressed ACF in the chemical model, but not the radiation model. In the chemical model, a low fermentable, soluble fiber prevent the development of colonic ACF just feeding fiber before, but not after a challenge of carcinogen. Also, a product of the colonic fermentation, butyric acid, prevented the development of ACF in the rat colon using the chemically-induced cancer model.