| Summary: | 碩士 === 臺北醫學大學 === 保健營養學研究所 === 98 === The purpose of this study was to investigate the effects of rice bran oil on colon carcinogenesis using a chemically induced animal model. F344 rats were fed a modified AIN-93G 14% high-fat diet: groups B and N, 14% soybean oil; group P, 14% soybean oil containing 0.04% piroxicam; group L, 5% rice bran oil and 9% soybean oil; group M, 9% rice bran oil and 5% soybean oil; group H, 14% rice bran oil. All rats except for those in group B were administrated with 1,2-dimethylhydrazine/dextran sulfate sodium (DMH/DSS) to induce colitis-related colon carcinogenesis. After 13 weeks of experimental period, DMH/DSS-treated rats were sacrificed and colons were removed to examine for aberrant crypt foci (ACF), mucin and mucin-depleted foci (MDF). All rats'' liver and colon tissues were examined for superoxide dismutase (SOD) activity, catalase (CAT) activity, glutathione (GSH) level and thiobarbituric acid reactive substances (TBARS) level. The results showed that all doses of rice bran oil significantly reduced the numbers of total ACF, total aberrant crypts (AC), small and large ACF. Moreover, all doses of rice bran oil significantly reduced the numbers of ACF producing both sulfomucin and sialomucin (MIX-ACF), ACF producing sialomucin (SIM-ACF), MDF and tumors, especially in group H. Group N had significantly lower hepatic GSH level, SOD and CAT activity, and higher TBARS level than did group B. Groups M and H had significantly higher hepatic GSH level and SOD activity than did group N, and group H had significantly higher hepatic CAT activity than did group N. In addition, all doses of rice bran oil significantly reduced TBARS level as compared to group N. These results indicated that rice bran oil was able to increase hepatic antioxidant-associated parameters and reduced TBARS level, to inhibit colonic ACF formation, to modify mucin composition, and to inhibit MDF and tumor formation, suggesting that rice bran oil has the potential for deferring colon carcinogenesis.
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