植物分离蛋白对卵巢切除大鼠血脂代谢的影响

Effects of Plant Protein Isolate on Serum Lipids Metabolism in Ovariectomized Rats

目的:研究大米分离蛋白和大豆分离蛋白对因雌性激素缺乏引起的高胆固醇血症的影响。方法:将24只Wistar成年雌鼠随机分为4组。3组大鼠进行双侧卵巢切除手术,分别喂食添加20%酪蛋白(对照组)、大米分离蛋白或大豆分离蛋白的饲料。另1组进行卵巢伪切除手术,喂食添加20%酪蛋白的对照饲料,喂养4周后解剖,测定血清和肝脏中胆固醇、甘油三酯浓度以及粪中胆汁酸排泄量和蛋白表观消化率等指标。结果:卵巢切除明显增加成年雌鼠血清和肝脏中胆固醇和甘油三酯浓度。与酪蛋白组相比,饲料中添加大豆分离蛋白能显著降低卵巢切除大鼠血浆总胆固醇和低密度脂蛋白及胆固醇浓度(p<0.05),但对血浆甘油三酯浓度无显著影响,同时明显降低肝重、肝脏中总脂、总胆固醇、游离胆固醇及甘油三酯总量,以及增加排粪量和胆汁酸排泄量,大豆分离蛋白表观消化率也明显比酪蛋白和大米分离蛋白高。大米分离蛋白对血脂没有明显降低效果,但肝脏总脂、总胆固醇、游离胆固醇和甘油三酯浓度明显低于酪蛋白饲料组,而排粪量、粪中胆汁酸排泄量和蛋白表观消化率则与酪蛋白组无显著差异。结论:抗消化蛋白对因雌性激素缺乏引起的高胆固醇血症有明显降低效果,可能的作用机制是由于该蛋白的低消化性干扰,肠道中胆汁酸代谢,增加粪中胆汁酸的排泄量来降低肝脏和血浆中胆固醇浓度。

Objective： To study the hypocholesterolemic effects of rice and soybean protein isolate on estrogen deficiencyinduced hypercholesterolemia in ovariectomized rats. Methods： 24 Wistar femal rats were divided into four groups. Three groups were double ovariectomized and fed the diets containing rice and soybean protein isolates as two experimental groups with 20% casein as control. The other group was sham-overiectomized and fed the diets containing 20% casein as control. All rats were dissected afer 4 weeks of feeding to assay concentrations of cholesterol, triacylglycerides in serum and liver and fecal excretion of bile acids and apparent protein digestibility. Results： Concentrations of cholesterol, triacylglycerides in serum and liver are significantly increased in OVX rats. Concentrations of serum total cholesterols, LDL and cholesterol are significantly lower in soybean isolate feed group than in casein feed group（p 〈0.05）, but triacylglycerides are effected with no significant difference. Liver weight, liver total lipids, total cholesterol, free cholesterol and total triacylglycerides are also significantly decreased. However, fecal excretion and fecal excretion of bile acids are being increased and apparent protein digestibility of soybean protein isolate group is higher than that of casein and rice protein isolate groups. Rice protein isolate group has no apparent effect on decreasing serum lipids, but liver total lipids, total cholesterol, free cholesterol and triacylglycerides of rice protein isolate group are significantly lower than those of casein group. But fecal excretion, fecal excretion of bile acids and apparent protein digestibility office protein isolate group has no apparent difference with casein group. Conclusions： Resistant protein may significantly decrease the serum cholesterol concentration in estrogen deficiency-induced hypercholesterolemia rats, because the hypocholesterolemic effect of resistant protein appears to be interfered with bile acids metabolism and fecal excretion increase in the intestinal pool.