Nagaoka Satoshi, Masaoka Motoki, Zhang Qing, Hasegawa Mineo, Watanabe Kenji
Department of Food Science, Faculty of Agriculture, Gifu University, Japan.
Lipids. 2002 Mar;37(3):267-72. doi: 10.1007/s11745-002-0890-6.
This experiment was designed to evaluate the effect of casein or ovomucin (OV) on the micellar solubility of cholesterol and the taurocholate binding capacity in vitro. We also evaluated the effects of casein or OV on cholesterol metabolism in rats and Caco-2 cells. OV had a significantly greater bile acid-binding capacity than that of casein in vitro. Micellar cholesterol solubility in vitro was significantly lower in the presence of OV compared to casein. The cholesterol micelles containing OV significantly suppressed cholesterol uptake by Caco-2 cells compared to the cholesterol micelles containing casein. Consistent with these in vitro findings, OV-feeding significantly increased the fecal excretion of bile acids or cholesterol compared with casein-feeding. Serum total cholesterol was significantly lower in rats fed OV than in those fed casein. The concentrations of total lipids in liver were significantly lower in the OV-fed group compared with the casein group. These results suggest that the suppression of cholesterol absorption by direct interaction between cholesterol mixed micelles and OV in the jejunal epithelia is part of the mechanism underlying the hypocholesterolemic action of OV. OV may also inhibit the reabsorption of bile acids in the ileum, thus lowering the serum cholesterol level.
本实验旨在评估酪蛋白或卵粘蛋白（OV）对胆固醇胶束溶解度以及体外牛磺胆酸盐结合能力的影响。我们还评估了酪蛋白或OV对大鼠和Caco-2细胞胆固醇代谢的影响。在体外，OV的胆汁酸结合能力显著高于酪蛋白。与酪蛋白相比，在OV存在的情况下，体外胶束胆固醇溶解度显著降低。与含酪蛋白的胆固醇胶束相比，含OV的胆固醇胶束显著抑制Caco-2细胞对胆固醇的摄取。与这些体外研究结果一致，与喂食酪蛋白相比，喂食OV显著增加了胆汁酸或胆固醇的粪便排泄量。喂食OV的大鼠血清总胆固醇显著低于喂食酪蛋白的大鼠。与酪蛋白组相比，OV喂养组肝脏中的总脂质浓度显著降低。这些结果表明，胆固醇混合胶束与OV在空肠上皮细胞中的直接相互作用抑制胆固醇吸收是OV降胆固醇作用机制的一部分。OV还可能抑制回肠中胆汁酸的重吸收，从而降低血清胆固醇水平。
