Hong Mee Young, Bancroft Laura K, Turner Nancy D, Davidson Laurie A, Murphy Mary E, Carroll Raymond J, Chapkin Robert S, Lupton Joanne R
Department of Nutrition and Food Science and the Center for Environmental and Rural Health, Texas A&M University, College Station, TX 77843, USA.
Nutr Cancer. 2005;52(2):166-75. doi: 10.1207/s15327914nc5202_7.
To determine if dietary fish oil protects against colon cancer by decreasing oxidative DNA damage at the initiation stage of colon tumorigenesis, oxidative DNA damage, proliferation, and apoptosis were assessed by colonic crypt cell position using quantitative immunohistochemical analysis of 8-hydroxydeoxyguanosine (8-OHdG), Ki-67, and TUNEL assay, respectively. Sixty rats were provided one of two diets (corn oil or fish oil) and dextran sodium sulfate (DSS, an inducer of oxidative DNA damage) treatments (no DSS, 3% DSS, or DSS withdrawal). Fish oil feeding resulted in lower 8-OHdG levels (P = 0.038), higher levels of apoptosis (P = 0.035), and a lower cell proliferative index (P = 0.05) compared with corn oil feeding. In the top third of the crypt, fish oil caused an incremental stimulation of apoptosis with increased DNA damage (P = 0.043), whereas there was no such relationship with corn oil. Because polyps and tumors develop from DNA damage that leads to loss of growth and death control, the significant difference in fish oil vs. corn oil on these variables may account, in part, for the observed protective effect of fish oil against oxidatively induced colon cancer.
为了确定膳食鱼油是否通过在结肠癌发生起始阶段减少氧化性DNA损伤来预防结肠癌，分别使用8-羟基脱氧鸟苷（8-OHdG）、Ki-67的定量免疫组织化学分析以及TUNEL检测，根据结肠隐窝细胞位置评估氧化性DNA损伤、增殖和凋亡情况。给60只大鼠提供两种饮食（玉米油或鱼油）以及葡聚糖硫酸钠（DSS，一种氧化性DNA损伤诱导剂）处理（无DSS、3% DSS或DSS撤药）。与喂食玉米油相比，喂食鱼油导致8-OHdG水平降低（P = 0.038）、凋亡水平升高（P = 0.035）以及细胞增殖指数降低（P = 0.05）。在隐窝的上三分之一处，鱼油随着DNA损伤增加导致凋亡的渐进性刺激（P = 0.043），而玉米油则不存在这种关系。由于息肉和肿瘤由导致生长和死亡控制丧失的DNA损伤发展而来，鱼油与玉米油在这些变量上的显著差异可能部分解释了所观察到的鱼油对氧化诱导的结肠癌的保护作用。
