成纤维母细胞样基质细胞在人工假体无菌性松动中的作用

目的研究成纤维母细胞样基质细胞（FBSCs）在人工关节置换术后无菌性松动中的作用。方法酶消化法从人工假体周围假膜标本中分离FBSCs并作体外培养并加入骨水泥颗粒,检测FBSCs核因子KB受体激动剂配体（RANKL）和肿瘤坏死因子（TNFα）mRNA表达的变化。同时FBSCs与外周血单个核细胞共培养,加入巨噬细胞克隆集落刺激因子、骨保护素或抗TNFα中和抗体;检测破骨细胞的形成并比较其生物学活性。结果假膜组织来源的FBSCs均表达RANKL和TNFamRNA;骨水泥颗粒组FBSCs RANKL和TNFα mRNA的表达量分别是对照组的1．9倍和2．1倍（P=0．002;P=0．004）。共培养细胞培养终末时见到抗酒石酸磷酸酶染色阳性的多核细胞,同时象牙磨片上有虫噬样骨吸收陷窝的形成;OPG完全阻断共培养组抗酒石酸磷酸酶染色阳性多核细胞以及虫噬样骨吸收陷窝的形成,而TNFα中和抗体对上述现象无显著抑制作用。结论骨水泥颗粒显著增强人工假体周围假膜中FBSCs RANKL和TNF mRNA的表达;FBSCs通过表达RANKL而支持外周血单个核细胞分化为具有骨吸收活性的破骨细胞。     

局部注射重组人转化生长因子对大鼠正畸牙移动的影响

目的:探讨局部注射重组人转化生长因子 (rhTGF -β1)对大鼠正畸牙移动速度的影响。方法:80只模型大鼠随机分为实验组和对照组,每组又按1、4、7、10和14 d再分为5个小组,每小组8只。实验组从加力的第1天开始,每2 d在大鼠加力侧上颌第一磨牙颊侧黏膜下注射rhTGF-β1 0.1 mL(5 ng/mL),对照组注射相同容量的PBS。加力后依实验设计时间分别处死每1小组大鼠。体视显微镜观察并采集图像,运用计算机图像分析软件测量牙移动的距离,同时应用TRAP组织化学染色观察不同时段压力侧破骨细胞数量的变化,采用SPSS 17.0 软件包对数据进行统计学分析。结果:局部注射rhTGF-β1的牙移动速度较对照组快,在加力后第7天,牙移动距离差异显著(P<0.05);第10天和第14天相比,差异显著(P<0.01)。实验组压力侧破骨细胞的TRAP阳性细胞数较对照组显著增多(P<0.01)。结论:局部注射rhTGF-β1增强了大鼠正畸牙破骨细胞的活性,促进了破骨细胞的骨吸收功能,加速了正畸牙移动。     

Historically significant events in the discovery of RANK/RANKL/OPG

After it was suggested 30 years ago that the osteoblast lineage controlled the formation of osteoclasts, methods were developed that established this to be the case, but the molecular controls were elusive. Over more than a decade much evidence was obtained for signaling mechanisms that regulated the production of a membrane - bound regulator of osteoclastogenesis, in the course of which intercellular communication in bone was revealed in its complexity. The discovery of regulation by tumor necrosis factor ligand and receptor families was made in the last few years of the twentieth century, leading since then to a new physiology of bone, and to exciting drug development.     

外泌体在骨代谢中的作用

外泌体是多种细胞在生理或病理状态下主动分泌到细胞外的纳米级囊泡,富含蛋白质、核酸、脂质等生物活性物质,参与细胞间信息交流与传递.目前已有研究表明,外泌体能通过信号蛋白、miRNAs等调控成骨细胞、破骨细胞及骨髓间充质干细胞的增殖、分化,介导骨生成和骨吸收过程,在多种骨代谢疾病的发生、发展中起重要作用.     

microRNA调节血管钙化

在冠状动脉疾病的患者中血管钙化是非常普遍的,血管钙化与主要不良心血管事件发生有关,可增加心血管死亡风险。血管钙化的发病机制复杂,目前公认的是类似于骨骼的形成。血管平滑肌细胞(SMC)转分化为成骨样细胞、钙磷平衡的失调、破骨细胞活性和矿物质吸收能力的降低,在血管钙化过程中都扮演着不可或缺的角色。最近的研究发现,microRNA(miRNA)作为一个血管钙化的重要调控物,是通过引起SMC复杂的基因重组和其他相关细胞的功能反应而参与这个过程的。本文将详细介绍miRNA在血管钙化中的调节作用。     

Mechanisms of altered bone remodeling in children with type 1 diabetes

Bone loss associated with type 1 diabetes mellitus (T1DM) begins at the onset of the disease, already in childhood, determining a lower bone mass peak and hence a greater risk of osteoporosis and fractures later in life. The mechanisms underlying diabetic bone fragility are not yet completely understood. Hyperglycemia and insulin deficiency can affect the bone cells functions, as well as the bone marrow fat, thus impairing the bone strength, geometry, and microarchitecture. Several factors, like insulin and growth hormone/insulin-like growth factor 1, can control bone marrow mesenchymal stem cell commitment, and the receptor activator of nuclear factor-κB ligand/osteoprotegerin and Wnt-b catenin pathways can impair bone turnover. Some myokines may have a key role in regulating metabolic control and improving bone mass in T1DM subjects. The aim of this review is to provide an overview of the current knowledge of the mechanisms underlying altered bone remodeling in children affected by T1DM.     

CSF-1, RANKL and OPG regulate osteoclastogenesis during murine tooth eruption

During tooth eruption, osteoclast-mediated bone resorption predominates in alveolar bone along the occlusal surface rather than in bone basal to the tooth. CSF-1, RANKL and OPG, regulatory molecules essential for osteoclastogenesis, are expressed during eruption. However, it is unclear if these cytokines exhibit an expression pattern that correlates with sites of osteoclastogenesis in vivo. To address this issue, mouse mandibles, isolated from 1 to 14 days postnatal, were analysed for osteoclast activity using tartrate-resistant acid phosphatase (TRAP) staining as well as colony-stimulating factor-1 (CSF-1), receptor activator of nuclear factor-kappa B ligand (RANKL) and osteoprotegerin (OPG) mRNA expression using in situ hybridisation. Results showed that CSF-1, RANKL and OPG are expressed in a distinct temporal and spatial manner. In the occlusal region, osteoclast activity was maximal at day 5 and correlated with a relative high expression of CSF-1 and RANKL compared to OPG. In basal bone at this time point, osteoclast activity decreased despite persistent CSF-1 expression and was associated with increased expression of OPG compared to RANKL. By day 8, osteoclastogenesis declined and correlated with upregulation of OPG at the occlusal and basal regions, with this effect continuing throughout eruption. These findings suggest that the spatiotemporal pattern and relative abundance of CSF-1, RANKL and OPG during eruption are key determinants of site-specific osteoclast activity in bone surrounding the tooth. Targeting these cytokines to specific regions in alveolar bone may provide a mechanism for regulating osteoclastogenesis in dental disorders associated with altered tooth eruption.     

胰岛素样生长因子1(IGF-1)通过抑制RUNX2促进骨折愈合的机制研究

目的 探讨IGF-1信号促进骨折愈合的分子机制。方法 建立IGF-1成骨细胞特异性敲除小鼠的骨折模型,三点弯曲试验分析IGF-1敲除组（KO）与对照组（Con）的最大载荷。通过Q-PCR和TRAP染色方法检测KO组和Con组成骨细胞分化指标的表达破骨细胞的个数。分离并培养来自KO组和Con组小鼠的骨髓基质细胞（BMSC）,经瞬时转染si-RUNX2,采用Q-PCR和Western blot法检测转染前后BMSC细胞中成骨细胞分化指标的表达情况。结果 骨折后10天和21天,KO组的最大载荷明显低于Con组。与Con组相比,KO组愈伤组织的OCN和ALP表达显著降低,而RUNX2则明显提高,且TRAP阳性破骨细胞数显著减少,表明敲除IGF-1破坏了小鼠的骨折愈合能力。通过瞬时转染si-RUNX2于BMSC细胞,发现干扰RUNX2表达能够有效挽救因IGF-1敲除而破坏的成骨细胞分化潜能。表明RUNX2参与IGF-1信号调节的骨折愈合过程。结论 IGF-1能够诱导成骨细胞分化和破骨细胞形成,其诱导成骨细胞分化的机制可能是通过抑制RUNX2的表达,这为骨折愈合的机制提供新的理论依据。