牛源乳铁蛋白对体外培养大鼠成骨细胞RANKL和OPG mRNA表达的影响

目的观察牛源乳铁蛋白对成骨细胞核因子κβ受体活化受体（RANKL）／护骨素（OPG）mRNA表达的影响。方法体外分离培养新生大鼠成骨细胞，分别观察不同浓度乳铁蛋白处理不同时间对成骨细胞RANKL／OPGmRNA表达的影响。采用半定量RT-PCR方法检测RANKL／OPGmRNA。结果乳铁蛋白呈时间和剂量依赖性地刺激大鼠成骨细胞OPGmRNA的表达，而抑制RANKLmRNA的表达，使RANKL／OPG值降低。结论乳铁蛋白通过调节成骨细胞RANKL／OPG的基因表达，从而抑制破骨细胞介导的骨吸收。     

乳铁蛋白对大鼠成骨细胞增殖与分化的影响

目的观察乳铁蛋白(Lf)对大鼠成骨细胞增殖分化的影响,初步探讨Lf对成骨细胞的作用机制。方法用不同浓度的Lf干预成骨细胞,在不同时间分别测定细胞数目的增殖、细胞内碱性磷酸酶活性,并用半定量RT-PCR法检测成骨细胞内RANKL/OPG mRNA基因的表达。结果Lf呈时间和浓度依赖性地促进大鼠成骨细胞增殖及碱性磷酸酶活性,每组实验在不同时间的差异均有显著的统计学意义(P<0.05),其中400μg/ml组在72h时细胞增殖数目达到最大。在碱性磷酸酶活性方面,400μg/ml组在72h时则有所下降。不同浓度Lf、不同作用时间均能促使成骨细胞中OPG mRNA表达增加,同时抑制RANKL mRNA表达。结论Lf能促进成骨细胞的增殖分化,并且能够调节成骨细胞RANKL/ OPG mRNA表达,从而抑制破骨细胞介导的骨吸收。     

柚皮苷对共培养体系中成骨细胞活性及破骨细胞分化的影响

目的研究在成骨细胞-破骨细胞共培养体系中,柚皮苷对成骨细胞活性和破骨细胞分化的影响。方法将成骨细胞(MC3T3-E1细胞株)和破骨细胞(RAW264.7细胞株)以2∶1的比例分别培养至Transwell小室的上室和下室。根据培养基是否含有柚皮苷分为对照组和柚皮苷(2ng/ml组、20 ng/ml组、200 ng/ml组),培养7 d后对下室破骨细胞进行TRAP染色和骨吸收陷窝鉴定;荧光定量PCR分析成骨细胞骨保护素(osteoprotegerin,OPG)、核因子κB受体活化因子配体(receptor activator for nuclear factor-κB ligand,RANKL)基因和破骨细胞分化基因活化T细胞核因子-1(NFATc-1)、活化T细胞核因子-2(NFATc-2)和核因子κB受体激活蛋白(receptor activator of NF-κB,RANK)的相对表达量。结果与对照组相比,柚皮苷可以促进成骨细胞OPG、RANKL的表达量且可提高OPG/RANKL的比值,差异有统计学意义(P0.05);20 ng/ml柚皮苷TRAP(+)细胞数(5.82±3.37)明显少于对照组(20.56±7.69),差异有统计学意义(P0.05);柚皮苷可抑制破骨细胞NFATc-1、NFATc-2的表达,促进RANK的表达,差异有统计学意义(P0.05)。结论柚皮苷可促进共培养条件体系中成骨细胞OPG和RANKL的表达以及抑制破骨细胞的分化,与上调OPG/RANKL的比值有关。     

护骨素及配体在卵巢切除大鼠骨组织的蛋白表达和细胞定位

目的对卵巢切除和假切大鼠骨组织中护骨素（OPG）和配体（RANKL）的表达进行比较，观察不同分化阶段成骨细胞的OPG和RANKL表达变化，深入地探讨成骨细胞对破骨细胞发生的调控作用。方法9月龄雌性大鼠分为卵巢切除组和假切组，相同条件喂养3月后处死，取材制作骨病理切片，用免疫组织化学方法测定大鼠股骨OPG和RANKL的蛋白表达，用图像分析软件对蛋白表达情况半定量分析，对各组数据和组织形态进行分析比较。结果OPG和RANKL蛋白在骨组织表达相对稳定。RANKL主要表达在增殖活跃的成骨细胞和幼稚的骨细胞，OPG主要表达在成熟骨细胞和静息骨衬里细胞。与假切组相比，卵巢切除组骨组织内RANKL表达升高（P〈0．01），OPG表达降低（P〈0．05）。结论卵巢切除后骨组织中RANKL/OPG升高，破骨细胞活性增强，骨转换加快。不同发育阶段的成骨细胞对破骨细胞有不同的调节作用，幼稚阶段表现出对破骨细胞的诱导作用，而成熟阶段则表现为抑制作用。     

金属离子刺激小鼠成骨细胞骨保护素及其配体表达的实验研究

目的在人工全髋关节翻修术中发现假体周围大量金属离子聚集和NF-κB受体活化因子配体(receptor activator of NF-κBligand,RANKL)表达的增加,通过观察Co2+、Cr3+对小鼠成骨细胞RANKL、骨保护素(osteoprotegerin,OPG)表达的影响,探讨金属离子与假体无菌性松动关系。方法取浓度为1×105个/mL体外培养的小鼠成骨细胞,根据培养基不同分两组:实验组采用含10mg/L CoCl2及150mg/L CrCl3溶液的培养基;对照组采用不含金属离子的培养基。培养24、48h,采用RT-PCR和ELISA法检测RANKL、OPG mRNA及蛋白表达。结果RT-PCR检测示培养24、48h两组均见RANKL、OPGmRNA的表达,实验组表达量较对照组高,以RANKL增加显著,差异有统计学意义(P0.05);培养24、48h,实验组RANKL/OPG mRNA的比值分别为0.860、1.232,较对照组0.695、0.688明显增加,差异有统计学意义(P0.05)。ELISA检测显示,实验组RANKL、OPG蛋白表达量较对照组明显增多,差异有统计学意义(P0.05)。结论Co2+、Cr3+可刺激小鼠成骨细胞RANKL、OPG mRNA的表达并促进其蛋白的分泌,以RANKL增加显著,从而促进破骨细胞的形成与活化以及假体无菌性松动的发生。     

神经肽P物质调控脊髓损伤大鼠骨髓间充质干细胞源性成骨细胞RANKL/OPG的表达

目的研究P物质(substance P,SP)对脊髓损伤(spinal cord injury,SCI)大鼠骨髓间充质干细胞(mesenchymal stem cells,MSCs)源性成骨细胞RANKL/OPG表达的影响,从而揭示SP在骨代谢中的作用。方法 20只雄性6w龄SD大鼠制作脊髓损伤模型。3w后测定胫骨骨密度,收集股骨髓腔细胞悬液,MSCs诱导成骨细胞培养至第二代,用10-8mol/L SP进行作用。用免疫细胞化学的方法进行RANKL和OPG的染色并定量分析;用半定量RT-PCR分析RANKL、OPG、Col1α1、OCN基因的表达变化;用EIA方法检测细胞培养基中RANKL和OPG蛋白的表达变化。结果 3w时SCI组胫骨的骨密度明显低于SHAM组,骨密度的下降既发生在胫骨近端干骺端(-26.3%,P0.05),又发生在胫骨干(-21.2%,P0.05)。通过免疫细胞化学的方法进行定量分析显示,SP处理后比不加处理因素的MSCs源性成骨细胞表达RANKL显著增加(P0.05)。SP作用72h后MSCs源性成骨细胞RANKL的表达显著上调(+160.2%,P0.01),OPG的表达显著下调(-45.5%,P0.01),OCN的表达显著下降(-42.9%,P0.01)。结论 SP在成骨细胞与破骨细胞偶联的关系中发挥重要作用。它既可以对成骨细胞产生直接作用(抑制OCN的基因表达),又可以通过成骨细胞间接的作用于破骨细胞(促进RANKL表达,抑制OPG表达),增强破骨细胞的活性,导致骨吸收和骨形成失衡,最终发生骨质疏松。     

橄榄苦苷对破骨细胞增殖影响的实验研究

目的探讨橄榄苦苷不同药物浓度及不同作用时间对破骨细胞增殖的影响。方法破骨细胞的制备,采用sRANKL与M-CSF诱导小鼠单核细胞RAW264.7细胞获得破骨细胞。设置实验组:4组分别加入400μg/mL、200μg/mL、100μg/mL、50μg/mL橄榄苦苷,另设空白对照组。运用抗酒石酸酸性磷酸酶染液试剂盒进行破骨细胞TRAP染色鉴定,并采用Cell Counting Kit法(CCK法)检测应用不同浓度橄榄苦苷及不同作用时间抑制破骨细胞增殖的情况。结果与空白对照组比较,400μg/mL、200μg/mL、100μg/mL橄榄苦苷对破骨细胞的增殖均具有明显抑制作用。当药物作用时间为24 h及72 h时,400μg/mL橄榄苦苷对破骨细胞增殖的抑制作用最强,当药物作用时间为48 h时,200μg/mL橄榄苦苷对破骨细胞增殖的抑制作用最强,差异有统计学意义(P0.05);50μg/mL橄榄苦苷对破骨细胞的增殖无明显抑制作用,差异不具有统计学意义(P0.05)。结论橄榄苦苷可能通过破坏破骨细胞细胞膜的完整性抑制破骨细胞的增殖。     

BMP-2对体外培养人牙囊细胞表达OPG和RANKL的影响

目的：研究BMP-2对体外培养人牙囊细胞表达OPG和RANKL的影响。方法：第5代人牙囊细胞免疫组化染色,检测人牙囊细胞中OPG和RANKL蛋白的表达;第5代人牙囊细胞与浓度为100ng/ml的BMP-2共同孵育0h、1h、3h、6h、12h、18h,RT-PCR法检测OPG和RANKL基因表达的变化。结果：人牙囊细胞OPG、RANKL免疫组化染色阳性;100ng/ml的BMP-2上调OPG蛋白的分泌,最佳效应时间为12～18h,下调RANKL基因的表达,最佳效应时间为6～12h。结论：人牙囊细胞存在OPG、RANKL蛋白的表达;100ng/ml的BMP-2可增强人牙囊细胞OPG蛋白分泌和基因表达,减弱RANKL基因的表达,降低RANKL/OPG的比值,抑制破骨细胞的形成。     

OPG/RANKL/RANK系统与软骨及软骨下骨

OPG/RANKL/RANK系统在调节骨代谢和骨重塑方面具有重要作用。成骨细胞表达的核因子-κB受体活化因子配体(RANKL)与破骨细胞表面的核因子-κB受体活化因子(RANK)结合促进破骨细胞分化成熟,骨保护素(OPG)则结合RANKL而抑制这一功能。研究表明,OPG/RANKL/RANK系统在软骨及软骨下骨内也有表达,可能成为类风湿关节炎及骨关节炎的治疗靶点。该文就OPG/RANKL/RANK系统在软骨及软骨下骨内表达及其作用研究进展作一综述。     

维持性血液透析患者血清骨保护素与肾性骨营养不良的关系

骨保护素（OPG）是近年来在肿瘤坏死因子受体超家族中发现的一种具有调控破骨细胞产生和活化作用的生物活性物质。它与核因子κB活化子受体配体（RANKL,亦称骨保护素配体OPGL）和核因子κB活化子受体（RANK）组成的分子调控系统是体内维持骨代谢平衡的重要分子机制。在正常的骨转化中成骨细胞表面表达RANKL．它与破骨细胞前体或破骨细胞表面的RANK结合后启动了信号转导，使破骨细胞增殖和活化．溶骨活动增强。同时成骨细胞分泌OPG，它与RANK竞争性的抑制RANKL使溶骨作用不致过度强烈。     

Adiponectin stimulates RANKL and inhibits OPG expression in human osteoblasts through the MAPK signaling pathway.

Our study indicates that recombinant adiponectin induced RANKL and inhibited OPG expression in human osteoblasts through the AdipoR1/p38 MAPK pathway, and these responses contributed to the adiponectin-induced osteoclasts formation in the co-culture of osteoblast and peripheral blood monocytes systems. These findings showed that adiponectin increased osteoclast formation indirectly through stimulating RANKL and inhibiting OPG production in osteoblasts. It also suggests the pharmacological nature of recombinant adiponectin that indirectly induces osteoclasts formation. INTRODUCTION: Recently, adiponectin has emerged as an element in the regulation of bone metabolism, but the mechanism remains. This study was undertaken to investigate the action of adiponectin on osteoclastogenesis through revealing RANKL and osteoprotegerin (OPG) expression in osteoblasts and osteoclast formation. MATERIALS AND METHODS: Real-time quantitative PCR and ELISA were used to detect RANKL and OPG mRNA and protein expression in cultured human osteoblasts. The involved signal pathway was studied using mitogen-activated protein kinase (MAPK) inhibitor and adiponectin receptor 1 (AdipoR1) siRNA. The effects of recombinant adiponectin on osteoclasts formation also were examined in the co-culture systems of osteoblast and peripheral blood monocytes (PBMCs) systems or purified CD14 + PBMCs cultures. RESULTS: Our study showed that recombinant adiponectin induced RANKL and inhibited OPG mRNA expression in human osteoblasts in a dose- and time-dependent manner. Adiponectin also increased soluble RANKL and decreased OPG secretion in osteoblasts conditioned media. Suppression of AdipoR1 with siRNA abolished the adiponectin-regulated RANKL and OPG mRNA expression in osteoblasts. Furthermore, pretreatment of osteoblasts with the MAPK inhibitor SB203580 abolished adiponectin-regulated RANKL and OPG mRNA expression. Adiponectin induced osteoclast formation in the co-culture systems of osteoblast and PBMCs systems, and OPG entirely blocked this response. However, adiponectin had no direct effect on the differentiation of osteoclast precursor purified CD14 + PBMCs. CONCLUSIONS: These data indicate that recombinant adiponectin induced RANKL and inhibited OPG expression in human osteoblasts through the AdipoR1/p38 MAPK pathway, and these responses contributed to the adiponectin-induced osteoclast formation in the co-culture of osteoblast and PBMCs systems. These findings showed that adiponectin increased osteoclast formation indirectly through stimulating RANKL and inhibiting OPG production in osteoblasts. It suggests the pharmacological nature of recombinant adiponectin that indirectly induces osteoclasts formation.     

Liver X receptors orchestrate osteoblast/osteoclast crosstalk and counteract pathologic bone loss

Osteoporosis is characterized by enhanced differentiation of bone‐resorbing osteoclasts, resulting in a rapid loss of functional trabecular bone. Bone‐forming osteoblasts and osteoblast‐derived osteocytes perform a key role in the regulation of osteoclast development by providing both the pro‐osteoclastogenic cytokine receptor activator of NF‐κB ligand (RANKL) and its natural decoy receptor osteoprotegerin (OPG). By regulating the RANKL/OPG ratio, osteoblasts hence determine the rate of both osteoclast differentiation and bone turnover. Here, we describe a novel role for liver X receptors (LXRs) during the crosstalk of bone‐forming osteoblasts and bone‐resorbing osteoclasts. By using a system of osteoblast/osteoclast cocultures, we identify LXRs as regulator of RANKL expression and the RANKL/OPG ratio in osteoblasts. Activation of LXRs drastically reduced the RANKL/OPG ratio and interfered with osteoblast‐mediated osteoclast differentiation in vitro. During an ovariectomy (OVX)‐induced model of postmenopausal osteoporosis, the application of an LXR agonist shifted the RANKL/OPG ratio in vivo, ameliorated the enhanced osteoclast differentiation, and provided complete protection from OVX‐induced bone loss. These results reveal an unexpected involvement of LXRs in the regulation of bone turnover and highlight a potential role for LXRs as novel targets in the treatment of osteoporosis and related diseases. © 2012 American Society for Bone and Mineral Research.     

Prostate-specific antigen stimulates osteoprotegerin production and inhibits receptor activator of nuclear factor-kappaB ligand expression by human osteoblasts

BACKGROUND: Prostate cancer cells produce a large amount of prostate-specific antigen (PSA), which is widely used as a marker for this cancer. Even though it is widely used in the diagnosis of prostate cancer, many aspects of the pathophysiologic role of PSA in bone metastasis remain obscure. The receptor activator of nuclear factor-kappaB ligand (RANKL) is essential for the activation of osteoclasts, while osteoprotegerin (OPG) neutralizes the action of RANKL. Various substances that act on bone have been shown to modulate the production of RANKL and OPG by osteoblasts. METHODS: In this study, we investigated the effect of PSA on the expression of OPG and RANKL mRNA and on protein production in human osteoblast-like cells. RESULTS: After addition of PSA and culture for 72 h, OPG mRNA expression and protein secretion by MG-63 and SaOS-2 cells showed a concentration-dependent increase. When osteoblasts were incubated with PSA (100 ng/ml), OPG mRNA expression and protein secretion increased with the passage of time. alpha1 -antichymotrypsin (ACT), which inactivates the serine protease activity of PSA, inhibited the increase of OPG mRNA expression and protein production in response to PSA, and this effect of PSA was also inhibited by anti-transforming growth factor-beta antibody. CONCLUSIONS: Based on our findings, PSA acts on human osteoblast-like cells via its own serine protease activity and promotes osteoblast differentiation. In addition, PSA stimulates OPG production and inhibits RANKL expression of osteoblasts, and inhibits bone resorption by osteoclasts, suggesting that it contributes to the characteristic osteoblastic features of bone metastases of prostate cancer.     

Production of IL-7 is increased in ovariectomized mice,but not RANKL mRNA expression by osteoblasts/stromal cells in bone,and IL-7 enhances generation of osteoclast precursors in vitro

Osteoclastogenic cytokines produced by T and B lineage cells and interleukin (IL)-7-induced expansion of the pool size of osteoclast precursors have been suggested to play an important role in acceleration of osteoclastogenesis induced by estrogen deficiency. However, the contribution of increased RANKL produced by osteoblasts/stromal cells to increase osteoclastogenesis in a mouse model of estrogen-deficient osteoporosis and in vitro effects of IL-7 on osteoclast precursor generation remain controversial. Thus, we investigated the effect of ovariectomy (OVX) of mice on production of RANKL, osteoprotegerin (OPG), and IL-7 in bone and the effect of IL-7 on osteoclast precursor generation in vitro. OVX did not significantly stimulate mRNA expressions of RANKL and OPG in whole femurs. Because the epiphysis, but not the femoral shaft (diaphysis) or bone marrow, is the main site of osteoclastogenesis, it is important to specifically analyze mRNA expression by osteoblasts/stromal cells at these parts of the femur. Therefore, we isolated RNA from bone marrow cell-free epiphysis, diaphysis, and flushed-out bone marrow and examined mRNA expression. The results showed no significant changes of RANKL and OPG mRNA expression in any part of the femur. In addition, OVX did not significantly affect RANKL and OPG mRNA expression by the adherent stromal cells isolated from flushed-out bone marrow cells but did stimulate RANKL mRNA expression by B220⁺ cells in the nonadherent cell fraction. On the other hand, OVX increased IL-7 mRNA expression in the femur as well as IL-7 concentrations in bone fluid. In cultures of unfractionated bone cells isolated by vigorous agitation of minced whole long bones to release the cells tightly attached to the bone surfaces, but not in cocultures of clonal osteoblasts/stromal cells and flushed-out bone marrow cells, IL-7 stimulated generations of osteoclasts as well as osteoclast precursors. These data suggest that increased RANKL production by osteoblasts/stromal cells is unlikely to play a central role in acceleration of osteoclastogenesis in estrogen deficiency of mice and that IL-7 stimulates osteoclast precursor generation, presumably through an action of IL-7 on the cells attached to bone rather than on cells contained in the bone marrow cell population.     

Heparin enhances osteoclastic bone resorption by inhibiting osteoprotegerin activity

Heparin is a highly sulfated glycosaminoglycan and has been shown to activate osteoclastic bone resorption though how is not yet clear. Here we investigate the molecule involved in heparin-induced activation of osteoclasts using an in vitro osteoclast culture assay. The formation and activation of osteoclasts are induced by receptor activator of NFkappaB ligand (RANKL) on osteoblasts, and inhibited by osteoprotegerin (OPG), a decoy receptor of RANKL, which is secreted from osteoblasts. In a coculture of mouse bone marrow cells and osteoblasts treated with 1,25-dihydroxyvitamin D(3) and prostaglandin E(2) on dentin slices, the bone marrow cells differentiate into osteoclasts, and resorption pits are formed on the dentin slices. Addition of heparin, various glycosaminoglycans, and chemically modified heparins to the coculture reveals that heparin enhances the pit-forming activity of osteoclasts, and this effect of heparin on the activation of osteoclasts is dependent on its sugar chain structure. By contrast, mRNA expression levels of RANKL, RANK, and OPG in the coculture are not altered by heparin treatment. Furthermore, neither RANK nor RANKL binds to heparin, suggesting that heparin does not directly interact with these proteins. Instead, heparin specifically binds to OPG and prevents OPG-mediated inhibition of osteoclastic bone resorption in the coculture. Heparin treatment does not enhance osteoclastic bone resorption in a monoculture of osteoclasts derived from bone marrow cells, and in the coculture using osteoblasts from OPG-deficient mice. A (125)I-OPG binding assay showed that OPG binds to osteoblasts and that this binding is inhibited by the addition of heparin, suggesting that OPG binds to RANKL on the osteoblast membrane and that heparin blocks this interaction. These results demonstrate that heparin enhances osteoclastic bone resorption by inhibiting OPG activity.     

Osteoprotegerin and its Ligand: A New Paradigm for Regulation of Osteoclastogenesis and Bone Resorption

In just 3 years, striking new advances have been made in understanding the molecular mechanisms that govern the crosstalk between osteoblasts/stromal cells and hematopoietic osteoclast precursor cells that leads to osteoclastogenesis. Led first by the discovery of osteoprotegerin (OPG), a naturally occurring protein with potent osteoclastogenesis inhibitory activity, rapid progress was made to the isolation of RANKL, a transmembrane ligand expressed on osteoblasts/stromal cells that binds to RANK, a transmembrane receptor on hematopoietic osteoclast precursor cells. The interaction of RANK and RANKL initiates a signaling and gene expression cascade that results in differentiation and maturation of osteoclast precursor cells to active osteoclasts capable of resorbing bone. OPG acts as a decoy receptor, binding to RANKL and blocking its interaction with RANK, inhibiting osteoclast development. Many of the calciotropic hormones and cytokines, including 1,25(OH)₂D₃, PTH, PGE₂ and IL-11, appear to act through a dual capacity to inhibit production of OPG and stimulate production of RANKL. Estrogen, on the other hand, appears to inhibit production of RANKL and RANKL-stimulated osteoclastogenesis. Recently, the results of the first clinical trial with OPG supported its potential as a therapeutic agent for diseases such as osteoporosis. The new understanding provided by the RANK/RANKL/OPG paradigm for both differentiation of osteoclasts and their activation has had tremendous impact on the field and opened new avenues for development of possible treatments of diseases characterized by excessive bone resorption.     

Influence of glucocorticoids on human osteoclast generation and activity.

Using human peripheral blood mononuclear cells as osteoclast precursors, we showed that dexamethasone stimulated osteoclast generation at a pharmacological concentration but did not affect the life span of human osteoclasts. Dexamethasone also dose-dependently increased signals for osteoclastogenesis. INTRODUCTION: Glucocorticoid-induced osteoporosis is a common and serious disease. Glucocorticoids predominantly affect osteoblast proliferation and life span. Much of the bone loss is caused by reduced bone formation, but there is also an element of increased bone resorption. MATERIALS AND METHODS: Human peripheral blood mononuclear cells were cultured on whale dentine and induced to differentiate to osteoclasts by RANKL and human macrophage-colony stimulating factor (M-CSF). Osteoclast activity was quantified by pit area. RANKL and osteoprotegerin (OPG) expression in osteoblasts were measured by real-time RT-PCR. RESULTS: In the early phase of osteoclast generation (0-16 days), cultures from two different donors showed that dexamethasone at 10(-8) M increased pit area by 2.5-fold, whereas lower concentrations had no effect. At the highest dexamethasone concentration (10(-7) M), pit area was reduced. In 21-day cultures from three other donors, a similar increase was seen with dexamethasone at 10(-8) M. There was, however, no evidence of increased life span of osteoclasts with dexamethasone. In human primary osteoblasts, dexamethasone dose-dependently reduced OPG and increased RANKL expression as measured by quantitative real time RT-PCR. CONCLUSION: These data provide some explanation at a cellular and molecular level for the observed increase in bone resorption seen in patients treated with glucocorticoids and indicate that there are clear direct effects of glucocorticoids on bone resorption in human cell systems that may differ from other species.     

葡萄糖对人牙周膜成纤维细胞OPG、RANKLmRNA表达的影响

目的：以体外培养的人牙周膜成纤维细胞（HPDLF）为研究对象,观察不同浓度的葡萄糖对HPDLF中骨保护素（OPG）、核因子KB受体活化剂配体（RANKL）mRNA表达的影响,探讨葡萄糖在牙槽骨吸收中的作用。方法：组织块法体外原代培养HPDLF并鉴定,选择4-8代的HPDLF作为实验的靶细胞,不同浓度的葡萄糖（0、5．5、11．1、16．7、22．2、33．3mmol／1）干预HPDLF,半定量逆转录聚合酶链反应（RT-PCR）检测HPDLF中OPG、RANKL mRNA的表达。结果：高浓度的葡萄糖可下调HPDLF中OPG mRNA的表达,呈剂量依赖性;可上调RANKL mRNA的表达,也呈剂量依赖性,且使RANKL／OPG mRNA的比值随着葡萄糖浓度的增高而呈现持续上升的趋势。结论：糖尿病时,牙周组织中高浓度的葡萄糖,可下调OPG的表达,上调RANKL的表达,使RANKL／OPG的比值升高,调节破骨细胞分化,刺激骨吸收,导致牙槽骨的破坏,加重牙周病的病情。     

二甲双胍对去卵巢大鼠骨质疏松症的影响及机制研究

目的 以雌二醇为对照,观察二甲双胍(metformin, MF)对去卵巢大鼠骨密度及骨矿含量的影响,并从细胞、分子水平探究MF可能的骨保护机制。方法 将60只雌性SD大鼠随机均分4组：假手术（SHAM）组、去卵巢（OVX）组、去卵巢+二甲双胍（OVX+MF）组和去卵巢+雌二醇(OVX+E2 )组。分组灌胃给药60 d后测量大鼠右侧胫骨骨密度和骨矿含量;分离培养各组大鼠骨髓间充质干细胞（BMSCs）并诱导其向成骨细胞分化,用MTT法测定细胞活性及增殖能力;测定各组碱性磷酸酶（ALP）活性、矿化结节数目、钙含量以及I型胶原（collagen type I）、骨钙素（OC）、骨保护素 (OPG)、NFκB受体的配体 (RANKL)、白细胞介素-6（IL-6）基因表达水平。结果 与OVX组相比,OVX+MF组和OVX+E2组成骨细胞的增殖能力与ALP活性明显增强,骨密度、骨矿含量以及钙沉积量显著增加(P均<0.05),且两组collagen type I、OC、OPG mRNA的表达水平显著升高,而RANKL、IL-6mRNA表达明显受到抑制;但OVX+MF组去卵巢大鼠成骨细胞的增殖能力、ALP活性、钙沉积量、collagen type I、OC、OPG mRNA表达水平低于OVX+E2组,RANKL、IL-6mRNA表达高于OVX+E2组（P均<0.05）;与SHAM组比较,OVX+MF组的collagen type I、OC、OPG mRNA的表达水平更高（P<0.05）。结论 二甲双胍可能通过OPG/RANKL/RANK信号通路促进BMSCs向成骨细胞分化,有效逆转去卵巢大鼠骨质疏松的状态,这种潜在的骨保护作用可能会改善糖尿病引起的骨质疏松。