Zhao Zhaohui, Xu Zuyuan, Le Khuong, Azordegan Nazila, Riediger Natalie D, Moghadasian Mohammed H
Department of Human Nutritional Sciences, University of Manitoba, and Canadian Center for Agri-food Research in Health and Medicine, St Boniface Hospital Research Center, Winnipeg, Canada.
J Agric Food Chem. 2009 Jul 22;57(14):6455-60. doi: 10.1021/jf900090q.
Epidemiological studies have suggested that intake of whole grains is inversely associated with coronary artery disease. The mechanisms, however, are not completely clear. We tested the hypothesis that intake of wheat bran or corn bran would (1) increase the plasma concentration of phenolic antioxidants and (2) reduce atherosclerosis in apo E-knockout mice. Apo E-knockout (E-KO) mice were fed for 18 weeks with a 0.1% cholesterol-supplemented diet in the absence of grain brans or the presence of 1.7% yellow dent corn bran or 3.3% hard red spring wheat bran. The concentration of antioxidant ferulic acid in plasma and urine was measured by HPLC to monitor the bioavailability of grain phenolics. Plasma lipoprotein profiles were determined by a combination of HPLC and online enzymatic methods. Urinary 15-isoprostane F(2t), an in vivo LDL oxidation biomarker, and atherosclerotic lesions were analyzed by ELISA and histological methods, respectively. Dietary supplementation with corn or wheat bran resulted in a 4- and 24-fold increase, respectively, in urinary excretion of ferulic acid. The urinary recovery rate of ferulic acid from the two brans in apo E-KO mice was approximately 1.9-2.9%. Dietary corn bran but not wheat bran also significantly increased the concentration of total ferulic acid in plasma. Nevertheless, the supplementation with either bran product for 18 weeks did not significantly alter the urinary excretion of 15-isoprostane F(2t), change the lipoprotein profiles, nor reduce the atherosclerotic lesion development in this animal model. The results suggest that phenolic antioxidants from the two types of bran may not be sufficient to reduce atherosclerosis in this animal model.
流行病学研究表明，全谷物的摄入与冠状动脉疾病呈负相关。然而，其机制尚不完全清楚。我们检验了以下假设：摄入麦麸或玉米麸会（1）提高血浆中酚类抗氧化剂的浓度，以及（2）减轻载脂蛋白E基因敲除小鼠的动脉粥样硬化。给载脂蛋白E基因敲除（E-KO）小鼠喂食18周含0.1%胆固醇的饮食，该饮食中不含谷物麸皮，或含有1.7%的黄粒马齿玉米麸或3.3%的硬红春麦麸。通过高效液相色谱法测定血浆和尿液中抗氧化剂阿魏酸的浓度，以监测谷物酚类的生物利用度。通过高效液相色谱法和在线酶法相结合的方式测定血浆脂蛋白谱。分别采用酶联免疫吸附测定法和组织学方法分析尿液中的15-异前列腺素F（2t）（一种体内低密度脂蛋白氧化生物标志物）和动脉粥样硬化病变。膳食补充玉米麸或麦麸分别使阿魏酸的尿排泄量增加了4倍和24倍。载脂蛋白E基因敲除小鼠从这两种麸皮中摄取的阿魏酸的尿回收率约为1.9%-2.9%。膳食补充玉米麸而非麦麸也显著提高了血浆中总阿魏酸的浓度。然而，在这个动物模型中，补充任何一种麸皮产品18周均未显著改变15-异前列腺素F（2t）的尿排泄量，未改变脂蛋白谱，也未减轻动脉粥样硬化病变的发展。结果表明，这两种麸皮中的酚类抗氧化剂可能不足以减轻该动物模型中的动脉粥样硬化。
