黄精多糖对骨质疏松性骨折大鼠骨修复及骨代谢因子的影响

Effect of polysaccharide on bone repair and bone metabolic factor in rats with osteoporotic fracture

目的研究黄精多糖对骨质疏松性骨折的防护作用及对骨修复及骨代谢因子的影响。方法将SD大鼠随机分为假手术组、模型组、对照组和低、中、高剂量实验组,每组12只。通过完整摘除两侧卵巢构建骨质疏松大鼠模型,8周后再手术折断右侧股骨干中段制备骨质疏松骨折模型,假手术组仅摘除卵巢周围脂肪组织,低、中、高剂量实验组灌服100,500,1000 mg·kg-1黄精多糖,对照组灌服尼尔雌醇0. 21 mg·kg-1;模型组、假手术组均按照10 mL·kg-1灌胃生理盐水,每天1次;各组均连续灌服8周。用酶联免疫吸附(ELISA)法测定大鼠血清碱性磷酸酶(ALP)、骨保护素(OPG)、抗酒石酸酸性磷酸酶(TRAP)、Ⅰ型原胶原分子N端前肽(PINP)、骨钙素(BGP)指标水平;用Micro-CT及双能X线骨密度仪检测大鼠骨密度(BMD),三点弯曲实验检测骨质疏松症骨折大鼠胫骨生物力学;以蛋白质印迹法(WB)检测大鼠胫骨组织中G蛋白偶联受体48(GPR48)及骨成型蛋白-2(BMP-2)蛋白表达水平。结果与假手术组比较,模型组血清TRAP、PINP含量升高,ALP、OPG、BGP降低;与模型组比较,中、高剂量实验组和阳性对照组血清TRAP、PINP含量降低,ALP、OPG、BGP升高(P <0. 05);假手术组,模型组、对照组和低、中、高剂量实验组股骨近端BMD分别为(0. 14±0. 02),(0. 06±0. 01),(0. 13±0. 02),(0. 07±0. 01),(0. 09±0. 02),(0. 12±0. 01) g·cm-1,胫骨组织GPR48蛋白相对表达量分别为1. 02±0. 09,0. 13±0. 06,0. 92±0. 09,0. 13±0. 04,0. 69±0. 11,0. 98±0. 17,BMP-9蛋白相对表达量分别为1. 26±0. 09,0. 32±0. 06,1. 16±0. 25,0. 36±0. 03,0. 75±0. 11,1. 23±0. 06。与假手术组比较,模型组大鼠胫骨最大载荷、弹性载荷、BMD及GPR48和BMP-2蛋白相对表达量均降低,而中、高剂量实验组和对照组上述数据均明显升高(P <0. 05)。结论黄精多糖可能通过调控骨修复及骨代谢因子进而提高骨质疏松症骨折大鼠生物力学性能及BMD。

Objective To investigate the protective effect of polygonatum on osteoporotic fracture and its effect on bone repair and bone metabolic factors.Methods SD rats were randomly divided into sham-operation group,model group,control group and low,middle,high dose experimental groups,12 rats in each group.The osteoporotic rat model was established by complete ovariectomy,and then the right femoral shaft was broken 8 weeks later to prepare the osteoporotic fracture model.The sham-operation group was only removed the adipose tissue around the ovary.The low,middle,high dose experimental groups were given polygonatum 100,500,1000 mg·kg-1,while the control group was fed with nylestriol 0.21 mg·kg-1.The model group and sham-operation group were fed with normal saline 10 mL·kg-1 once a day.All were administered continuously for 8 weeks.Serum levels of alkaline phosphatase(ALP),osteoprotegerin(OPG),tartrate-resistant acid phosphatase(TRAP),procollagen typeⅠN-terminal propeptide(PINP)and bone gla protein(BGP)were measured by automatic biochemical instrument and enzyme-linked immunosorbent assay(ELISA).Bone mineral density(BMD)was measured by micro-CT and dual-energy X-ray absorptiometry,and osteoporotic bone mineral density was measured by three-point bending test.The expression of G protein-coupled receptor 48(GPR48)and bone morphogenetic protein-2(BMP-2)in tibia tissue of rats were detected by Western blot(WB).Results Compared with sham-operation group,the serum TRAP and PINP levels in model group increased,while ALP,OPG and BGP levels decreased(P<0.05);compared with model group,the serum TRAP and PINP levels in middle,high dose experimental groups and control group decreased,while ALP,OPG and BGP levels increased(P<0.05);BMD in sham-operation group,model group,control group and low,middle,high dose experimental groups were(0.14±0.02),(0.06±0.01),(0.13±0.02),(0.07±0.01),(0.09±0.02),(0.12±0.01)g·cm-1,the relative expression levels of GPR48 protein in tibia were 1.02±0.09,0.13±0.06,0.92±0.09,0.13±0.04,0.69±0.11,0.98±0.17,the relative expression levels of BMP-9 were 1.26±0.09,0.32±0.06,1.16±0.25,0.36±0.03,0.75±0.11,1.23±0.06.Compared with sham-operation group,the maximum tibial load,elastic load,BMD,GPR48 and BMP-2 protein expression in model group decreased significantly,while those in middle,high dose experimental groups and control group increased significantly(P<0.05).Conclusion Polygonatum may improve the biomechanical properties and bone mineral density of op fracture rats by regulating bone repair and bone metabolic factors.