Preventive effects of brown rice, rice bran and polished rice on preneoplastic lesions of colon in rats

• Main Authors: Tsui-Chuan Chou, 周翠娟
• Other Authors: 施純光
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/62285366358593121184

碩士 === 臺北醫學大學 === 保健營養學研究所 === 97 === The purpose of this study was to investigate the effects of brown rice, rice bran and polished rice on preneoplastic lesions of colon. F344 rats were fed control diet (C), 40% brown rice diet (BR), 1.1% rice bran diet (LB), 2.2% rice bran diet (MB), 4.4% rice bran diet (HB), 8.9% polished rice diet (LR), 17.8% polished rice diet (MR) and 35.6% polished rice diet (HR) and administrated 1,2-dimethylhydrazine (DMH) by i.p. injection. After 17 weeks of experimental period, rats were sacrificed and colons were removed to examine for aberrant crypt foci (ACF), mucin and mucin-depleted foci (MDF). Colonic mucosa was examined for pro-inflammatory cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) protein expression. Liver and plasma were examined for thiobarbituric acid reactive substances (TBARS) level. Liver was examined for superoxide dismutase (SOD), catalase (CAT) activity and glutathione (GSH) level. The results showed that rice bran significantly reduced the number of total ACF, total aberrant crypts (AC), ACF containing 1 or 2 crypts and small ACF (P<0.05). Rice bran reduced the number of large ACF and ACF secreting both sulfomucin and sialomucin (P<0.1). Brown rice and rice bran significantly reduced COX-2 protein expression of middle colonic mucosa (P<0.05). Brown rice, rice bran and polished rice did not significantly affect MDF, tumor formation, plasma and hepatic TBARS level, and hepatic antioxidant-associated parameters. This study indicates that rice bran inhibits colonic ACF formation, pro-inflammatory COX-2 protein expression of colonic mucosa and inhibits mucin alteration, suggesting that rice bran has the potential for deferring colon carcinogenesis.