Kruger Marlena C, Plimmer Gabrielle G, Schollum Linda M, Haggarty Neill, Ram Satyendra, Palmano Kate
Institute of Food, Nutrition and Human Health, Massey University, Private Bag 11222, Palmerston North, New Zealand.
Br J Nutr. 2005 Aug;94(2):244-52. doi: 10.1079/bjn20051454.
Bovine milk has been shown to contain bioactive components with bone-protective properties. Earlier studies on bovine milk whey protein showed that it suppressed bone resorption in the female ovariectomised rat. A new osteotropic component was subsequently identified in the whey basic protein fraction, but bone bioactivity may also be associated with other whey fractions. In the present study, we investigated whether acidic protein fractions isolated from bovine milk whey could prevent bone loss in mature ovariectomised female rats. Six-month-old female rats were ovariectomised (OVX) or left intact (sham). The OVX rats were randomised into four groups. One group remained the control (OVX), whereas three groups were fed various whey acidic protein fractions from milk whey as 3 g/kg diet for 4 months. Outcomes were bone mineral density, bone biomechanics and markers of bone turnover. Bone mineral density of the femurs indicated that one of the whey AF over time caused a recovery of bone lost from OVX. Plasma C-telopeptide of type I collagen decreased significantly in all groups except OVX control over time, indicating an anti-resorptive effect of whey acidic protein. Biomechanical data showed that the AF may affect bone architecture as elasticity was increased by one of the whey AF. The femurs of AF-supplemented rats all showed an increase in organic matter. This is the first report of an acidic whey protein fraction isolated from milk whey that may support the recovery of bone loss in vivo.
研究表明，牛乳含有具有骨骼保护特性的生物活性成分。早期对牛乳清蛋白的研究表明，它能抑制去卵巢雌性大鼠的骨吸收。随后在乳清碱性蛋白组分中鉴定出一种新的促骨成分，但骨骼生物活性也可能与其他乳清组分有关。在本研究中，我们调查了从牛乳清中分离出的酸性蛋白组分是否能预防成熟去卵巢雌性大鼠的骨质流失。将6月龄雌性大鼠去卵巢（OVX）或假手术（sham）。将去卵巢大鼠随机分为四组。一组作为对照组（OVX），而另外三组以3 g/kg的日粮喂食来自乳清的各种乳清酸性蛋白组分，持续4个月。观察指标为骨矿物质密度、骨生物力学和骨转换标志物。股骨的骨矿物质密度表明，随着时间的推移，其中一种乳清酸性蛋白组分能使去卵巢大鼠流失的骨量得到恢复。除OVX对照组外，所有组的血浆I型胶原C端肽随时间显著降低，表明乳清酸性蛋白具有抗骨吸收作用。生物力学数据显示，其中一种乳清酸性蛋白组分可能会影响骨结构，因为它增加了骨弹性。补充乳清酸性蛋白组分的大鼠股骨的有机质均有所增加。这是首次报道从乳清中分离出的酸性乳清蛋白组分可能有助于体内骨质流失的恢复。
