锶盐与模拟失重大鼠骨细胞的凋亡

Effects of strontium ranelate on osteocyte apoptosis in rats under simulated weightlessness

背景:模拟失重促进成骨细胞、骨细胞凋亡,而锶能降低失重状态下骨组织中成骨细胞、骨细胞凋亡率,促进骨形成。目的:观察锶盐对失重状态下骨组织中细胞凋亡的防治效应。方法:5周龄SD大鼠建立失重动物模型,在悬吊前3d或悬吊时开始以锶盐灌胃。建模后7d,使用全自动生化仪检测大鼠血清中钙、磷、碱性磷酸酶水平,放射免疫分析法测定骨钙素质量浓度,原位细胞凋亡检测技术检测骨组织中细胞凋亡,免疫组化方法检测骨组织中Fas蛋白水平。结果与结论:模型组大鼠血清中碱性磷酸酶、骨钙素水平均显著低于相应对照组(P<0.05),但血钙,磷浓度均较相应对照组升高(P<0.05),骨组织中成骨细胞、骨细胞及骨髓间充质细胞凋亡指数、骨组织中Fas抗原水平均高于相应对照组(P<0.01)。悬吊前3d始及悬吊时始锶盐灌胃组碱性磷酸酶,骨钙素水平均显著高于模型组(P<0.05),而血钙、骨组织中成骨细胞、骨细胞及骨髓间充质细胞凋亡指数、骨组织中Fas抗原水平均显著低于模型组(P<0.05)。说明尾部悬吊模拟失重增加骨组织中Fas蛋白表达,从而增加大鼠骨组织中成骨细胞、骨细胞及骨髓间充质细胞凋亡,而锶盐可降低失重状态下大鼠骨组织Fas蛋白表达,从而降低成骨细胞、骨细胞及骨髓间充质细胞凋亡。

BACKGROUND：Simulated weightlessness promotes osteoblast and osteocyte apoptosis,and strontium can reduce the apoptosis rate of osteoblasts and osteocytes in bone tissues under weightlessness,and promote bone formation.OBJECTIVE：To investigate the prevention and therapeutic effect of strontium ranelate on cells apoptosis under weightlessness state.METHODS：SD rats aged 5 weeks were included in this study to establish weightlessness models,intragastrically administrating strontium ranelate 3 days before suspension or while suspension.At 7 days after model establishment,serum calcium,phosphorus,alkaline phosphatase levels were observed by using automatic biochemistry analyzer.The bone Gla protein concentration was determined by radio immunoassay.The cell apoptosis in bone tissues was detected with in situ cell apoptosis detection technology.The expressions of Fas protein in bone tissues were detected with SP immunohistochemical method.RESULTS AND CONCLUSION：In the model rats of simulated weightlessness,serum bone Gla protein and alkaline phosphatase contents were significantly lower than those in corresponding control group （P0.05）,whereas serum calcium and phosphorus concentrations were higher than that in control group （P0.01）,the apoptosis of osteoblasts,osteocytes and bone marrow mesenchymal cells,as well as Fas antigen in bone tissues were all increased compared with control group （P0.01）.Serum bone Gla protein and alkaline phosphatase content in rats treated with strontium ranelate 3 days before or while suspension were significantly higher than that in model group （P0.05）,whereas serum calcium,cell apoptosis and Fas expression in bone tissues were significantly lower than model group （P0.05）.Tail suspension stimulated weightlessness in rats can induce an increase of osteoblasts,osteocytes and bone marrow cells apoptosis associated with increased Fas expression in bone tissue,whereas strontium ranelate decreased Fas expression,accordingly,decreased osteoblasts,osteocytes and bone marrow cells apoptosis.