Kuratko C, Pence B C
Department of Pathology, Texas Tech University Health Sciences Center, Lubbock 79430.
J Nutr. 1992 Feb;122(2):278-82. doi: 10.1093/jn/122.2.278.
The polyunsaturated fatty acid composition of dietary fat has been associated with increased oxidant stress in tissues. We previously showed that antioxidant mechanisms in colon mucosa are affected by dietary fat. In this study, the colonic antioxidant response to treatment with the colon-specific carcinogen 1,2-dimethylhydrazine (DMH) was determined. Sprague-Dawley rats were fed one of four AIN-76A-based diets with varied fat content. The basal diet contained 5% corn oil, the menhaden oil diet contained 19% menhaden oil and 1% corn oil, the corn oil diet contained 20% corn oil and the beef tallow diet contained 19% beef tallow and 1% corn oil. Animals were given one or two intraperitoneal injections of either DMH (20 mg/kg) or 1 mmol/L EDTA. Homogenates of colon mucosa were assayed to determine activity of catalase, glutathione peroxidase, total superoxide dismutase, manganese superoxide dismutase, glutathione reductase and glutathione-S-transferase, as well as total glutathione concentration, thiobarbituric acid-reacting substances and nuclear aberrations. Total glutathione concentration was greater in rats fed all diets following two injections of DMH, whereas glutathione reductase activity remained unchanged relative to controls. Lipid peroxidation was highest in the group fed menhaden oil; nuclear aberrations were greatest in the corn oil-fed group. In conclusion, both type and amount of dietary fat modified the response of colon tissue to genotoxic challenge, but none of the diets seemed more protective than the others.
膳食脂肪中的多不饱和脂肪酸成分与组织中氧化应激增加有关。我们之前表明结肠黏膜中的抗氧化机制会受到膳食脂肪的影响。在本研究中，测定了结肠对结肠特异性致癌物1,2 - 二甲基肼（DMH）处理的抗氧化反应。将斯普拉格 - 道利大鼠喂食四种基于AIN - 76A且脂肪含量不同的饮食之一。基础饮食含有5%玉米油，鲱鱼油饮食含有19%鲱鱼油和1%玉米油，玉米油饮食含有20%玉米油，牛脂饮食含有19%牛脂和1%玉米油。给动物腹腔注射一次或两次DMH（20 mg/kg）或1 mmol/L乙二胺四乙酸（EDTA）。对结肠黏膜匀浆进行检测，以测定过氧化氢酶、谷胱甘肽过氧化物酶、总超氧化物歧化酶、锰超氧化物歧化酶、谷胱甘肽还原酶和谷胱甘肽 - S - 转移酶的活性，以及总谷胱甘肽浓度、硫代巴比妥酸反应物质和核畸变情况。在两次注射DMH后，喂食所有饮食的大鼠的总谷胱甘肽浓度均更高，而谷胱甘肽还原酶活性相对于对照组保持不变。喂食鲱鱼油的组脂质过氧化最高；喂食玉米油的组核畸变最大。总之，膳食脂肪的类型和量均改变了结肠组织对遗传毒性攻击的反应，但没有一种饮食似乎比其他饮食更具保护作用。
