大豆蛋白降低大鼠血浆胆固醇机理的初步探讨

Preliminary Study on Possible Mechanism of Soybean Protein Lowering Serum Cholesterol in Rats

目的 初步探讨大豆蛋白在大鼠体内降低血胆固醇的可能机理。方法 Wistar雌性大鼠 ,经 14天诱发高血胆固醇模型后 ,以 2× 2析因设计 ,分别喂饲含有 2 0 %酪蛋白或大豆分离蛋白和正常钙 (0 5 9% )或高钙浓度 (1 12 % )的纯合成高脂饲料 2 1天。实验结束前 ,测血浆总胆固醇浓度 ,收集 3天粪便 ,测定脂肪、钙、磷、镁的消化率及粪胆汁酸排出量。结果 同酪蛋白组相比 ,其它各组动物的血浆胆固醇浓度及钙和磷的消化率显著下降 (P <0 0 5 )。大豆蛋白组动物的脂肪消化率低于其它各组动物 ,而大豆蛋白高钙组动物的粪胆汁酸排出量高于其它各组动物。结论 本实验结果提示大豆蛋白在大鼠体内降血胆固醇机理可能与大豆蛋白本身的非磷酸化状态有关。

Objective To explore a possible mechanism preliminarily that soybean protein lowers serum cholesterol in rats.Methods Following 2 weeks of inducing hypercholesterolemia model successfully,femal Wistar rats were fed experimental diets containing 20% of protein each from either casein or soybean protein and either normal(0 59%) or high concentration of calcium(1 12%) respectively in a 2×2 factorial design.After 21 days' feeding,the concentration of serum total cholesterol of the rats was examined.Feces of rats were collected during the last 3 days of the trial,apparent digestibility of fat,calcium,phosphorus and magnesium was measured.Fecal bile acid excretion was determined.Results Compared with the rats in casein group,the serum total cholesterol,digestibility of calcium and phosphorus of rats in other groups were significantly low (P<0 05).The fat digestibility of rats in soybean protein group was lower than that in other groups.Whereas,the bile acid excretion of rats in the group fed soybean protein with high concentration of calcium was higher than that in other groups.Conclusion It indicated that the possible mechanism of soybean protein on lowering serum cholesterol in rats might relate to its non phosphorylated status.