猪皮胶原多肽螯合钙增加大鼠骨密度

摘要

以实验室制备的猪皮胶原多肽(collagen polypeptide,CP)和葡萄糖酸钙为原料,采用液体反应法合成胶原多肽螯合钙(calcium-binding CP,CP-Ca),并评价CP-Ca增加SD大鼠骨密度(bone mineral density,BMD)作用.将120 只断乳雌性4 周龄SD大鼠随机分为10 组:1)对照组(灌胃去离子水);2)低、中、高剂量CP-Ca组(139.28、278.55、557.10 mg/(100 g·d));3)低、中、高剂量CaCO3组(25、50、100 mg/(100 g·d));4)低、中、高剂量CP+CaCO3组(139.28 mg/(100 g·d)CP+25 mg/(100 g·d)CaCO3、278.55 mg/(100 g·d)CP+50 mg/(100 g·d)CaCO3、557.10 mg/(100 g·d)CP+100 mg/(100 g·d)CaCO3).所有实验大鼠饲喂基础饲料,自由饮用去离子水.实验过程中,每周测定大鼠的体质量和身长,灌胃第4周做3 d钙代谢实验.测定大鼠血清钙(S-Ca)、血清磷(S-P)浓度、碱性磷酸酶(alkaline phosphatese,ALP)活力、大鼠BMD和骨钙含量,并对大鼠股骨进行扫描电子显微镜(scanning electron microscope,SEM)分析.结果显示,中、高剂量CP-Ca组和高剂量CP+CaCO3组可以显著促进大鼠体质量增加和发育(P<0.05),CP-Ca效果更为明显.CP-Ca组和CP+CaCO3组的ALP活力显著低于对照组(P<0.05),而中、高剂量CP-Ca组和中、高剂量CP+CaCO3组BMD显著高于对照组(P<0.05),且高剂量CP-Ca组高于对应剂量CP+CaCO3组,各剂量CP-Ca组和CP+CaCO3组钙表观吸收率分别高于对应CaCO3组,CP-Ca具有促进大鼠骨生长、发育、骨钙沉积的作用.SEM结果显示,CP-Ca和CP+CaCO3能够预防和改善大鼠因长期钙摄入不足引起的骨质疏松症.CP-Ca溶解性高、解离性好,富含钙元素及多肽,具有预防骨质疏松症、增加骨质密度的作用.%In this paper, calcium-binding collagen polypeptide (CP-Ca) was synthesized by liquid-state reaction between collagen polypeptide prepared in our laboratory from pigskin gelatin and calcium gluconate, and the effect of CP-Ca on improving bone mineral density (BMD) in rats was investigated. Totally 120 female SD rats were equally divided into 10 groups: control group (deionized water by gavage), low-, middle- and high-dosage CP-Ca groups (139.28, 278.55 and 557.10 mg/(100 g·d)), low-, middle- and high-dosage CaCO3groups (25, 50 and 100 mg/(100 g·d)), and low-, middle- and high-dosage CP + CaCO3group (139.28 mg /(100 g·d) CP + 25 mg/(100 g·d) CaCO3, 278.55 mg/(100 g·d) CP + 50 mg/(100 g·d) CaCO3, 557.10 mg/(100 g·d) CP + 100 mg/(100 g·d) CaCO3). All rats were fed on a basic diet and deionized water. The body weight and length of the rats were recorded weekly. A three-day calcium metabolism experiment was carried out in the fourth week to estimate the apparent absorptivity of calcium. Serum calcium (S-Ca), serum phosphorusand (S-P), and alkaline phosphatese (ALP), BMD and bone calcium content were measured. The rat femurs were analyzed by scanning electron microscope (SEM). The results showed that CP-Ca at middle and high dosages and CP + CaCO3at high dosage could significantly promote body weight gain (P < 0.05), and the effect of CP-Ca was more apparent. CP-Ca and CP + CaCO3had obviously lower ALP activity than the control group (P < 0.05). CP-Ca and CP + CaCO3both at middle and high dosages significantly raised BMD compared to the control group (P < 0.05), and CP-Ca was more effective at the high dosage. At all dosages tested, CP-Ca and CP + CaCO3resulted in higher Ca bioavailability than CaCO3. CP-Ca could activate osteoblasts on the surface of bones, increase the density of bones and reduce bone calcium loss. Meanwhile, SEM revealed that CP-Ca and CP + CaCO3could prevent and improve osteoporosis caused by long-term calcium deficiency. CP-Ca was highly soluble, exhibited good dissociation ability, and was rich in calcium and polypeptides so than it can be used in functional foods and health products to prevent osteoporosis and improve BMD.