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。     

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.     

淫羊藿对体外培养成骨细胞影响的研究进展

淫羊藿是抗骨质疏松症中运用较多的中药。近年来,淫羊藿在抗骨质疏松方面的研究,无论从实验还是临床方面都取得了显著的成就。实验研究发现,淫羊藿不但可以促进体外成骨细胞增殖、分化,促进成骨作用;还可通过作用于成骨细胞相关基因的转录和信号通路的转导来影响成骨细胞的活性,为研制新型抗骨质疏松药物提供了前景。     

盐酸二甲双胍对成骨细胞增殖、BMP-2及Cbfa-1基因表达的影响

目的初步研究二甲双胍（MF）在体外对小鼠颅盖骨成骨细胞增殖、骨形态发生蛋白一2（BMP一2）及核心结合因子（Cbfa一1）mRNA表达的影响,探讨二甲双胍对骨代谢的可能作用机制。方法（1）分离培养原代颅盖骨成骨细胞并对其进行鉴定。（2）以乳鼠成骨细胞为体外实验模型,不同浓度（0、50、100、200、400Ixmol／L）的MF干预体外培养的成骨细胞24h后,M1vr法检测成骨细胞的增殖能力,实时荧光定量PCR法检测成骨细胞BMP-2及Cbfa-1基因表达。结果二甲双胍干预成骨细胞24h后,可促进成骨细胞的增殖,在浓度400μxmol／L的OD值最大为0．298±0．047（P〈0．05）;可促进BMP-2及Cbfa-1mRNA的表达,呈剂量效应关系。结论二甲双胍可促进成骨细胞的增殖和分化,可能通过调节BMP-2及Cbfa-1的表达,从而促进骨的形成。     

Effects of Ethyl Acetate Extract of Poncirus trifoliata Fruit for Glucocorticoid-Induced Osteoporosis

Poncirus trifoliata fruit (PTF) affects the digestive and cardiovascular systems, and kidney function. The authors studied the effects of ethyl acetate (EtOAc) extract of PTF on the activities of osteoblasts and in an animal model. The main compounds of the EtOAc extract, naringin and poncirin have been confi rmed by HPLC and NMR analysis. Effects of osteoblastic differentiation were mea-sured by alkaline phosphatase (ALP) activity, osteopontin (OPN) protein expression and osteoprotegerin (OPG) mRNA expression in MC3T3-E1 cells. Also, osteoclast differentiation was measured by multinucleated cells (MNCs) formation through tartrate resistance acid phosphatase (TRAP)-positive staining. Bone mineral density (BMD) was measured before and after treatment with EtOAc extract of PTF in prednisolone-induced osteoporotic mice. Dexamethasone (DEX) decreased OPN and OPG expression level in MC3T3-E1 cells and ALP activity was decreased by DEX dose-dependently. EtOAc extract of PTF recovered the levels of ALP activity, and the expression of OPN and OPG in MC3T3-E1 cells treated with DEX. In osteoclast differentiation, multinucleated TRAP-positive cell formation was significantly suppressed by the EtOAc extract of PTF. Total body BMD was restored by EtOAc extract of PTF in prednisolone-induced osteoporotic mice. In conclusion, EtOAc extract of PTF recovered DEX-mediated deteriorations in osteoblastic and osteoclastic functions, and increased BMD in glucocorticoid-induced osteoporosis.