黄芪多糖的提取及对体外培养成骨细胞成骨能力的影响

目的：了解黄芪多糖对体外培养成骨细胞增殖、分化能力的影响。方法：采用水煮醇沉法提取黄芪多糖,用ＴＬＣ进行定性,用比色法定量,用含高低两种剂量（０．５ｍ ｇ／ｍ ｌ,５．０ｍ ｇ／ｍ ｌ）的黄芪多糖的培养液体外培养成骨细胞,ＭＴＴ法及ＡＬＰ比活性测定观察成骨细胞增殖率及细胞活性变化。结果：低浓度黄芪多糖（０．５ｍ ｇ／ｍ ｌ）及高浓度黄芪多糖（５．０ｍ ｇ／ｍ ｌ）短期时（２ 天）促进成骨细胞增殖;高浓度（５．０ｍ ｇ／ｍ ｌ）长期（４ 天）抑制成骨细胞增殖,降低其活性。结论：黄芪多糖对成骨细胞增殖、活性有双向调节作用     

二甲胺四环素促进骨髓基质细胞增殖作用的研究

为弄清二甲胺四环素增加摘除卵巢的老龄大鼠骨量作用的细胞分子基础,采用细胞增殖曲线的绘制和碱性磷酸酶测定方法,了解二甲胺四环素对成骨细胞和骨髓基质细胞的影响,结果：二甲胺四环素在体外刺激骨髓基质细胞和成骨细胞增殖的作用,但抑制细胞的分化。     

外力诱导培养兔成骨细胞表达c—fos的实验研究

目的：探讨兔成骨细胞在机械力作用下将机械力信号转变为生物学效应的作用机理；方法：利用ＦＯＳ免疫组化技术观察在受到外力后培养的兔成骨细胞对立即早期基因ｃ－ｆｏｓ的蛋白产物（ＦＯＳ）的表达情况；结果：几乎所有的成骨细胞核均染成黄褐色，为ＦＯＳ免疫组化反应阳性；结论：ｃ－ｆｏｓ在兔成骨细胞的机械力信号向生物学效应转换的过程中可能发挥重要作用。     

Calcitonin has direct effects on3[H]-thymidine incorporation and alkaline phosphatase activity in human osteoblast-line cells

Summary Calcitonin had direct and dose-dependent actions on human osteoblast-line cells (in serum-free monolayer culture) to increase cell proliferation and alkaline phosphatase activity/mg cell protein. Salmon calcitonin increased (human osteosarcoma) SaOS-2 cell proliferation, as evidenced by dose-dependent increases in³[H]-thymidine incorporation into DNA (e.g., 153% of control after 20 h exposure at 0.1 nM,P<0.01), and MTT (thyzolyl blue) reduction/deposition (e.g., 161% of control after 72 h exposure at 0.03 nM). Continuous exposure was not required to elicit these proliferative responses. These effects were not unique to salmon calcitonin or to SaOS-2 cells. Similar effects were seen with human calcitonin (but not heat-inactivated human calcitonin) and with (human osteosarcoma) TE-85 cells and human osteoblast-line cells prepared from femoral heads. In addition to effects on cell proliferation, calcitonin also increased alkaline phosphatase-specific activity in SaOS-2 cells (e.g., 180% of control after 72 h of exposure to 0.1 nM salmon calcitonin,P<.005).     

Integrins,insulin like growth factors,and the skeletal response to load

Bone loss during skeletal unloading, whether due to neurotrauma resulting in paralysis or prolonged immobilization due to a variety of medical illnesses, accelerates bone loss. In this review the evidence that skeletal unloading leads to bone loss, at least in part, due to disrupted insulin like growth factor (IGF) signaling, resulting in reduced osteoblast proliferation and differentiation, will be examined. The mechanism underlying this disruption in IGF signaling appears to involve integrins, the expression of which is reduced during skeletal unloading. Integrins play an important, albeit not well defined, role in facilitating signaling not only by IGF but also by other growth factors. However, the interaction between selected integrins such as αυβ3 and β1 integrins and the IGF receptor are of especial importance with respect to the ability of bone to respond to mechanical load. Disruption of this interaction blocks IGF signaling and results in bone loss. The skeletal response to mechanical load is critical for maintenance of skeletal integrity. This review will assess the interacting roles that insulin like growth factor I (IGF-I) signaling and selected integrins play in this response. Skeletal unloading results in decreased integrin expression, resistance to the anabolic actions of IGF-I, and bone loss.     

Parathyroid hormone stimulates phosphoinositide metabolism and intracellular calcium mobilization in osteoblast-like clone MC3T3-E1 cells

The effects of parathyroid hormone (rat 1–34 fragment, rPTH) on phosphoinositide metabolism and intracellular Ca²⁺ mobilization were studied in a osteoblast-like clone MC3T3-E1 cells. rPTH caused a transient rise in intracellular Ca²⁺ in a dose-dependent manner. Significant Ca²⁺ increase was still observed under the extracellular Ca²⁺-free condition. In addition, 100nM rPTH stimulated rapid formation of both 1,2-diacylglycerol (1,2-DAG) and inositol 1,4,5-trisphosphate (Ins(1,4,5)P₃), indicating agonist-triggered hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP₂). The current observations suggested that the rPTH-induced increase of intracellular Ca²⁺ was in part due to internal Ca²⁺ release mediated by Ins(1,4,5)P₃. These results indicate possible involvement of phosphoiniositide metabolism in signal transduction of PTH-stimulated osteoblastic cells.     

Expression of bone sialoprotein (BSP) in developing human tissues

Summary Bone sialoprotein (BSP) and its messenger RNA were localized in developing human skeletal and nonskeletal tissues by means of immunohistochemistry andin situ hybridization. Both protein and mRNA were found in mature, bone-forming cells but not in their immature precursors. In addition, osteoclasts displayed positive immunostaining and high densities of autoradiographic grains byin situ hybridization experiments. BSP was expressed in fetal epiphyseal cartilage cells, particularly in hypertrophic chondrocytes of growth plates. Though neither the protein nor the mRNA were identified in a variety of other connective and nonconnective tissues, an unexpected finding was the expression of BSP in the trophoblast cells of placenta. These findings show that BSP is primarily an osteoblast-derived component of the bone matrix expressed at late stages of differentiation. We have also found that osteoclasts produce BSP, possibly as a mediator of cell attachment to bone.     

异黄酮类药Genistein对原代培养大鼠成骨细胞增殖、分化、钙含量及矿化功能的影响

目的：了解异黄酮类药Genistein对体外培养成骨细胞的作用。方法：应用MTT法、对硝基苯磷酸盐法，原子吸收分光光度法及茜素红染色方法观察Genistein对体外培养成骨细胞的增殖、ALP表达，基质钙含量及矿化结节形成的影响。结果：Genistein具有刺激成骨细胞增殖，提高ALP活性，细胞基质钙含量及矿化结节形成的数量的作用。结论：Genistein具有刺激体外培养成骨细胞增殖，分化成熟及促进矿化的作用。     

17β-雌二醇及补骨脂素对骨髓间充质细胞向成骨细胞分化的诱导作用

目的:观察17β-雌二醇对骨髓间充质干细胞向成骨细胞分化的诱导作用。方法:将大鼠的骨髓间充质干细胞(BMSCs)暴露于不同浓度的17β-雌二醇、补骨脂素增殖和成骨分化培养基。通过茜素红(Alizarin Red)染色法观察细胞增殖;通过酶联免疫吸附试验法(ELISA)和实时聚合酶链反应(PCR)评估成骨标志物Ⅰ型胶原的分泌水平以及关键因子RUNX2的表达情况。结果:与对照组比较,17β-雌二醇补充剂促进BMSCs增殖。BMSCs增殖添加的17β-雌二醇的不同剂量(0、0.001、0.01、0.1 nmol/L),有效地改善了骨髓间充质干细胞分泌Ⅰ型胶原的水平,RUNX2的mRNA也被上调。17β-雌二醇干预后第5天,Ⅰ型胶原表达显著升高(P<0.05),在17β-雌二醇干预的第7天,RUNX2 mRNA及蛋白表达随17β-雌二醇水平的增加而升高(P<0.05)。结论:17β-雌二醇联合补骨脂素可以作为一种有效的调节剂,以提高骨髓再生中MSC的能力。     

右归饮对体外成骨细胞增殖和分化影响的实验研究

目的在右归饮治疗激素性股骨头坏死的临床研究和动物实验研究基础上,进一步观察对体外成骨细胞增殖和分化的影响.方法采用血清药理学方法,对体外培养的大鼠成骨细胞作MTT法细胞增殖测定、PNPP法ALP活性测定、以及茜素红染色矿化结节计数.结果培养48、72h,10%和15%右归饮血清组的细胞增殖速度较对照组快(p＜0.05);培养72h,10%和15%右归饮血清组的ALP活性较对照组增加(p＜0.05);培养2w,矿化结节计数显示15%右归饮血清组多于对照组(p＜0.01).结论右归饮对体外大鼠成骨细胞的增殖和分化具有促进作用.