Hong Mee Young, Hoh Eunha, Kang Brian, DeHamer Rebecca, Kim Jin Young, Lumibao Jan
School of Exercise and Nutritional Sciences and
Graduate School of Public Health, San Diego State University, San Diego, CA; and.
J Nutr. 2017 Aug;147(8):1524-1530. doi: 10.3945/jn.117.251082. Epub 2017 Jun 28.
Epidemiologic, clinical, and experimental studies have suggested that fish oil (FO), a rich source of n-3 (ω-3) polyunsaturated fatty acids, protects against colon cancer. However, this message is confounded by the FDA's warning that the consumption of certain types of fish should be restricted because of contamination with persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs) and organochlorine pesticides. We examined FO contaminated with POPs (PCBs, dichlorodiphenyltrichloroethane, and chlordane) compared with unmodified FO on the risk factors of colon cancer development. Male Sprague-Dawley rats aged 28 d ( = 30) were allocated into 3 groups and fed 15% corn oil (CO), FO, or POP-contaminated FO for 9 wk with a subcutaneous injection of colon carcinogen azoxymethane at weeks 3 and 4. Colonic aberrant crypt foci (ACF) and cell proliferation were enumerated, and the gene expression of inflammation, antioxidant enzymes, and repair enzymes were determined with the use of real-time quantitative polymerase chain reaction analysis. FO-fed rats had a lower number of ACF (mean ± SE: 29 ± 4.0 for FO compared with 53 ± 8.4 for CO and 44 ± 4.6 for POP FO) and higher-multiplicity ACF than the CO and POP FO groups (4.7 ± 0.9 for FO compared with 11 ± 1.5 for CO and 9.6 ± 1.8 for POP FO) ( < 0.05). FO feeding lowered the proliferation index compared with the CO and POP FO feeding groups (18% ± 1.1% for FO compared with 25% ± 1.6% for CO and 23% ± 0.7% for POP FO) ( = 0.009). Superoxide dismutase [2.4 ± 0.6 relative quantification (RQ) for FO compared with 1.2 ± 0.2 RQ for CO and 1.3 ± 0.3 RQ for POP FO] and catalase gene expression (10 ± 2.0 RQ for FO compared with 5.4 ± 1.1 RQ for CO and 6.6 ± 1.5 RQ for POP FO) were higher in the FO group than in the CO and POP FO groups ( < 0.05). There were no differences between CO and POP FO on the variables. These results indicate that POPs in FO reduce the preventive effects of FO on colon carcinogenesis by increasing preneoplastic lesion formation through the downregulation of antioxidant enzyme expression and increasing cell proliferation in rats.
流行病学、临床和实验研究表明，富含n-3（ω-3）多不饱和脂肪酸的鱼油（FO）可预防结肠癌。然而，美国食品药品监督管理局（FDA）发出警告，由于某些鱼类受到多氯联苯（PCBs）和有机氯农药等持久性有机污染物（POPs）的污染，应限制食用某些类型的鱼类，这使得上述观点变得复杂。我们研究了受POPs（PCBs、二氯二苯三氯乙烷和氯丹）污染的FO与未改性的FO对结肠癌发生风险因素的影响。将28日龄的雄性斯普拉格-道利大鼠（n = 30）分为3组，分别喂食15%的玉米油（CO）、FO或受POPs污染的FO，持续9周，并在第3周和第4周皮下注射结肠癌致癌物偶氮甲烷。对结肠异常隐窝灶（ACF）和细胞增殖进行计数，并通过实时定量聚合酶链反应分析确定炎症、抗氧化酶和修复酶的基因表达。喂食FO的大鼠ACF数量较少（FO组平均±标准误：29±4.0，而CO组为53±8.4，受POPs污染的FO组为44±4.6），且ACF的多灶性高于CO组和受POPs污染的FO组（FO组为4.7±0.9，而CO组为11±1.5，受POPs污染的FO组为9.6±1.8）（P < 0.05）。与CO组和受POPs污染的FO组相比，喂食FO可降低增殖指数（FO组为1
