乳清碱性蛋白对实验大鼠和育龄女性骨密度的影响

目的探讨牛乳清碱性蛋白对实验大鼠和人体骨密度的影响。方法将44只雌性SD大鼠分为4个组。具体设置为：对照组、A组（每天给以每kg体重10mg乳清碱性蛋白）、B组（每天给以每kg体重20mg乳清碱性蛋白）和C组（每天给以每kg体重30mg乳清碱性蛋白）。连续灌胃90d后,分离股骨,分别测定股骨远心端,股骨干中段和股骨近心端骨密度。募集健康育龄女性志愿者63名（37．9±4．3）岁],随机分为对照组、甲组、乙组3组,其中：对照组饮用普通牛奶、甲组饮用含30mg乳清碱性蛋白的牛奶、乙组饮用含60mg乳清碱性蛋白的牛奶,每日1次,连续24周;于干预前后分别采用双能X射线测量腰椎（12-L4）、左侧股骨近端（股骨颈、大转子和Ward三角区）及右足跟骨骨密度;ELISA法测量血清骨特异碱性磷酸酶（BAP）、Ⅰ型胶原交联N末端肽（NTx）。结果A组大鼠的股骨远端骨密度高于对照组,而添加本试验剂量的乳清碱性蛋白牛奶对育龄女性受试者骨密度未见明显影响。结论本实验条件下,每日每kg体重10mg乳清碱性蛋白能提高实验大鼠的股骨密度,但未观察到对人体骨密度的影响。

Effect of the whey basic protein on bone mineral density

OBJECTIVE: To examine the effects of the whey basic protein on bone metabolism of Sperague-Dawley (SD) rats and healthy mid-aged women. METHODS: Forty-four female SD rats were randomized by weight into four groups of eleven rats each and fed 10 mg x kg BW(-1) x d(-1), 20 mg x kg BW(-1) x d(-1), 30 mg x kg BW(-1) x d(-1) of whey basic protein and control diet was given respectively by intragastrical injection for 90 days. Bone mineral density of femur was measured by dual-energy X-ray absorptiometry in vitro. Sixty-three health women (37.9 +/- 4.3) years old] were randomly assigned to treatment with placebo, 30 mg whey basic protein per day or 60 mg whey basic protein per day for 24 weeks. The bone mineral density (BMD) of the lumbar vertebrae L2-LA, femoral neck and right calcaneus of each subject were measured by dual-energy X-ray absorptiometry (DXA) at 0 and the 24th week of treatment. Serum bone specific alkaline phosphatase and N-telopeptide (NTX) were measured at 0 and the 14th week. RESULTS: The mean BMD value of the distal end of the femur in 10 mg x kg BW(-1) x d(-1) whey basic protein group was significantly higher than that of the control group at the end of the trail. But after treatment by doses of whey basic protein used in the study, there were no differences between the control group and others groups on bone mineral density in the human trail. CONCLUSION: Whey basic protein should enhance the bone mineral density of the rats' femur and no obvious effect was detected in the human trail.