Ni Weihua, Tsuda Yasuyuki, Takashima Shinichiro, Sato Hiroyoshi, Sato Masao, Imaizumi Katsumi
Laboratory of Nutrition Chemistry, Division of Bioresource and Bioenvironmental Sciences, Graduate School, Kyushu University, Fukuoka 812-8581, Japan.
Br J Nutr. 2003 Jul;90(1):13-20. doi: 10.1079/bjn2003878.
Our objective was to determine whether dietary plant proteins such as soya-protein isolate (SPI) and rice-protein isolate (RPI) compared with animal proteins, such as casein, could afford beneficial effects on atherosclerosis development in apolipoprotein E-deficient mice. In experiment 1, male and female mice were fed on a purified diet containing either casein, SPI or RPI for 9 weeks. The en face lesion area in the aorta (P<0.05) and the lesion size in the aortic root (P<0.05) in mice fed the casein-based diet were greater than those in the SPI or RPI groups. The plant protein groups had an increased concentration of serum l-arginine (P<0.05) and NO metabolites (NO2 plus NO3) (P<0.05) than did the casein group. The inhibitory effect of the plant proteins on the lesion formations was unrelated to gender and total serum cholesterol. In experiment 2, the l-arginine and l-methionine contents were the same in the l-arginine-supplemented casein-based and SPI-based diets, and between the l-methionine-supplemented SPI-based and the casein-based diets. Male mice were fed on the diets for 15 weeks. There were no significant differences in the en face lesion area and the lesion size between the casein group and the l-arginine-supplemented group, although the serum l-arginine (P<0.05) and NO2 plus NO3 (P<0.05) concentrations in the supplemented group were higher than those in the casein group. There were no significant effects of l-methionine supplementation on the lesion formations. In experiment 3, male mice were given the casein-based diet or the l-arginine-supplemented casein-based diet together with water or water containing an NO synthesis inhibitor for 9 weeks. When given the casein-based diet, the inhibitor drinking, compared with water drinking, resulted in a reduction of the serum NO2 plus NO3 concentration (P<0.01) and an increase in the en face lesion area (P<0.05) and the lesion size (P<0.01). When given the l-arginine-supplemented diet, the inhibitor drinking, compared with water drinking, resulted in no increase in the lesion area and size. These results demonstrate anti-atherogenic potentials of SPI- as well as RPI-derived proteins, but their l-arginine and l-methionine contents were not sufficient enough to explain the underlying mechanism(s).
我们的目标是确定与动物蛋白（如酪蛋白）相比，大豆分离蛋白（SPI）和大米分离蛋白（RPI）等膳食植物蛋白是否对载脂蛋白E缺陷小鼠的动脉粥样硬化发展具有有益作用。在实验1中，雄性和雌性小鼠被喂食含有酪蛋白、SPI或RPI的纯化饮食9周。喂食酪蛋白饮食的小鼠主动脉的正面病变面积（P<0.05）和主动脉根部的病变大小（P<0.05）大于SPI或RPI组。与酪蛋白组相比，植物蛋白组的血清L-精氨酸浓度（P<0.05）和NO代谢产物（NO2加NO3）浓度（P<0.05）有所增加。植物蛋白对病变形成的抑制作用与性别和总血清胆固醇无关。在实验2中，补充L-精氨酸的酪蛋白基饮食和SPI基饮食中的L-精氨酸和L-蛋氨酸含量相同，补充L-蛋氨酸的SPI基饮食和酪蛋白基饮食中的L-精氨酸和L-蛋氨酸含量也相同。雄性小鼠喂食这些饮食15周。酪蛋白组和补充L-精氨酸组之间的正面病变面积和病变大小没有显著差异，尽管补充组的血清L-精氨酸（P<0.05）和NO2加NO3（P<0.05）浓度高于酪蛋白组。补充L-蛋氨酸对病变形成没有显著影响。在实验3中，雄性小鼠被给予酪蛋白基饮食或补充L-精氨酸的酪蛋白基饮食，并同时饮用普通水或含有NO合成抑制剂的水9周。当给予酪蛋白基饮食时，与饮用普通水相比，饮用抑制剂导致血清NO2加NO3浓度降低（P<0.01），正面病变面积增加（P<0.05），病变大小增加（P<0.01）。当给予补充L-精氨酸的饮食时，与饮用普通水相比，饮用抑制剂并未导致病变面积和大小增加。这些结果证明了SPI和RPI衍生蛋白的抗动脉粥样硬化潜力，但其L-精氨酸和L-蛋氨酸含量不足以解释其潜在机制。
