Takahashi M, Fukutake M, Isoi T, Fukuda K, Sato H, Yazawa K, Sugimura T, Wakabayashi K
Cancer Prevention Division, National Cancer Center Research Institute, Chuo-ku, Tokyo, Japan.
Carcinogenesis. 1997 Jul;18(7):1337-42. doi: 10.1093/carcin/18.7.1337.
The effects of intragastric gavage administration of docosahexaenoic acid (DNA) , a major component of fish oil, on azoxymethane (AOM)-induced colon carcinogenesis in rats was investigated. Male F344 rats were treated with 15 mg/kg body wt of AOM once a week, for two weeks. The animals were given either 1 ml of DHA or water intragastrically 5 times a week, starting the day before the first carcinogen treatment. The numbers of AOM-induced aberrant crypt foci in the rats given DHA were 76% and 62% of the control values, at 4 and 12 weeks, respectively. After 36 weeks of DHA treatment, colon tumors were counted and examined histologically. The blood plasma levels of prostaglandin E2 (PGE2) and polyunsaturated fatty acids were also quantified. The incidences of colon cancer did not differ, being 96% and 92% in the AOM and AOM+DHA groups, respectively. Colon cancer multiplicity was, however, significantly decreased by the DHA treatment; 3.65 +/- 2.18 in the AOM group and 2.41 +/- 1.58 in the AOM+DHA group (P <0.01). Notably, the numbers of moderately differentiated adenocarcinomas in the middle and distal colon in the DHA-treated group were lower than in the AOM group. The levels of PGE2 and arachidonic acid in the blood plasma of DHA-treated rats were also significantly lower than in the AOM group. These results suggest that DHA exerts its inhibitory effect on colon carcinogenesis by modulating lipid metabolism and inhibiting the arachidonic cascade.
研究了鱼油的主要成分二十二碳六烯酸（DHA）经胃内灌胃给药对大鼠偶氮甲烷（AOM）诱导的结肠癌发生的影响。雄性F344大鼠每周一次接受15mg/kg体重的AOM处理，共两周。从第一次致癌物处理前一天开始，每周给动物胃内灌胃1ml DHA或水，共5次。给予DHA的大鼠中，AOM诱导的异常隐窝灶数量在4周和12周时分别为对照值的76%和62%。DHA处理36周后，对结肠肿瘤进行计数并进行组织学检查。还对血浆中前列腺素E2（PGE2）和多不饱和脂肪酸水平进行了定量。结肠癌的发生率没有差异，AOM组和AOM+DHA组分别为96%和92%。然而，DHA处理显著降低了结肠癌的多发性；AOM组为3.65±2.18，AOM+DHA组为2.41±1.58（P<0.01）。值得注意的是，DHA处理组中结肠中、远端中度分化腺癌的数量低于AOM组。DHA处理大鼠血浆中PGE2和花生四烯酸水平也显著低于AOM组。这些结果表明，DHA通过调节脂质代谢和抑制花生四烯酸级联反应对结肠癌发生发挥抑制作用。
