基于“脾主肉、肾主骨”理论探讨绝经后骨质疏松症的OPG/RANK/RANKL信号调控机制

中医理论传承"辨证论治"之道,强调人作为机体的整体性与统一性,肾主骨生髓为先天之本,脾主肌肉充四肢为后天之源,先后二天互资互生,共同维持人体正常的生理机能,但缺乏客观的分子生物学依据阐明其作用机理。OPG/RANK/RANKL信号转导系统的发现在骨代谢史上具有里程碑的意义,开创了中医药防治和研究绝经后骨质疏松症的新纪元,骨微观信息的改变就是从脾肾论治对骨代谢调控机制的效应表达。本文基于"脾主肉、肾主骨"理论,就绝经后骨质疏松症的病因病机及治法方药结合OPG/RANK/RANKL信号转导系统在骨代谢中的作用展开综述,旨在为绝经后骨质疏松症的中医药防治从分子生物学水平提供科学依据,以期更好地指导临床。     

益肾健骨膏对去卵巢骨质疏松大鼠骨代谢的影响

目的 探讨益肾健骨膏对去卵巢骨质疏松大鼠骨代谢的影响及可能机制。方法 50只雌性SD大鼠被随机分为假手术组、模型组、高剂量膏方组、低剂量膏方组、阳性药物组,每组10只。假手术组、模型组给予10 mL /（kg·d）生理盐水灌胃,低、高剂量膏方组分别给予2 g /（kg·d）、13 g/（kg·d）益肾健骨膏灌胃,阳性药物组灌服6.25 mg/（kg·w）阿仑膦酸钠维D3。治疗12周后检测大鼠腰椎骨密度和腰椎最大压缩载荷,通过Elisa检测血清骨代谢指标抗酒石酸酸性磷酸酶（TRACP）、骨保护素(OPG)、Ⅰ型前胶原氨基端原肽(PINP)、Ⅰ型胶原交联羧基端肽(CTX-Ⅰ),RT-PCR检测腰椎骨组织OPG、RANKL、RANK、TRAF6的 mRNA表达,RT-PCR及Western blot检测腰椎Notch1、Notch2、Jagged1、Jagged2的基因及蛋白表达。结果 益肾健骨膏治疗12周后,与模型组比较,高剂量膏方组大鼠腰椎骨密度、最大压缩载荷,血清PINP、OPG水平,骨组织Notch1、Notch2、Jagged1、Jagged2的mRNA和蛋白表达,OPG的mRNA表达显著升高（P<0.05）,而血清TRACP、CTX-Ⅰ水平,骨组织RANKL、RANK、TRAF6的mRNA表达显著降低（P<0.05）。结论 高剂量益肾健骨膏能改善去卵巢骨质疏松大鼠骨密度、骨强度及骨代谢,其作用机制可能与Notch通路及OPG/RANKL/RANK系统有关。     

从中医“虚”论治原发性骨质疏松症与OPG/RANK/RANKL信号通路的相关性

原发性骨质疏松症(primary osteoporosis,POP)是现代临床中常见的骨科疾病,其归属于中医学之"骨痿""骨痹""骨枯"等范畴。随着中医药事业的发展,中医学在POP的治疗中应用愈加广泛,且疗效显著,已受到学界的广泛认可。但遗憾的是,其缺乏现代研究理论依据的支撑。随着分子生物学的发展,OPG/RANK/RANKL信号通路的发现对中医学治疗此病具有重要意义。故笔者将从中医"虚"理论出发,并以中医学脏腑辨证理论为基础,借助现代分子生物学的研究成果OPG/RANK/RANKL信号通路,揭示中医治疗POP的OPG/RANK/RANKL信号通路表达机制,以期为中医学治疗POP提供科学理论依据。     

基于“肝主筋、肾主骨”理论探讨OPG/RANKL/RANK信号轴与绝经后骨质疏松症症的筋骨相关性

中医基础理论素有“肝主筋，肾主骨”之说，肝藏血主筋，筋束骨利关节，肾为先天之本，主骨而生髓，肝肾精血同源、筋骨相关，互资互生，二者共同介导机体器官、脏腑的发育、生长与衰退过程，尤其与骨细胞生长代谢机制关系密切。随着中医药分子生物学研究的深入，发现骨保护蛋白（OPG）/核因子-kB受体活化因子（RANK）/核因子-kB受体活化因子配体（RANKL）信号轴在骨代谢中发挥关键作用。本文基于“肝主筋，肾主骨”理论，从绝经后骨质疏松症症的病因病机出发，从“肝肾论治，筋骨并重”角度将OPG/RANKL/RANK信号转导系统与骨代谢内环境稳态相结合，为中医药柔肝补肾、调筋养骨机制提供分子生物学、筋骨力学依据支撑，以期进一步指导临床论治。     

基于OPG/RANKL/RANK轴观察加味阳和汤及其拆方对去卵巢骨质疏松大鼠的影响

目的观察加味阳和汤及其拆方对OPG、RANKL、RANK含量的影响,探讨其防治绝经后骨质疏松症可能的作用机制及组方配伍的合理性。方法选取48只雌性SD大鼠,加味阳和汤按君臣佐使关系拆方,将大鼠等量随机分为假手术组(SHAM)、模型组(OVX)、君药+臣药组(A组)、君药+臣药+佐药组(B组)、君药+臣药+佐药+使药组(C组)、戊酸雌二醇组(E2V)。除SHAM组外,均采用去卵巢骨质疏松大鼠模型,干预给药后(灌胃90 d),处死动物后取右侧股骨及胫骨通过双能X射线骨密度仪检测骨密度(bone mineral density,BMD)及骨矿含量(bone mineral content,BMC),取左侧股骨行HE染色观察骨显微结构,检测血清中骨代谢指标ALP、Ca~(2+)、P~(3-)、E2及血清OPG、RANKL、RANK含量。结果与SHAM组相比,OVX组大鼠股骨及胫骨BMD、BMC降低(P0.05),骨小梁变细、间隙增大、结构缺失,血清Ca~(2+)、P~(3-)、E2、OPG水平下降(P0.05),血清ALP、RANKL、RANK水平上升(P0.05);与OVX组比较,除A组大鼠股骨及胫骨BMD、BMC、血清Ca~(2+)、P~(3-)、E2、OPG、RANKL及B组P~(3-)水平无显著差异外(P0.05),各给药组大鼠股骨及胫骨BMD、BMC均显著升高(P0.05),骨小梁增多、间隙减小、结构趋向完整,血清Ca~(2+)、P~(3-)、E2、OPG水平上升(P0.05),血清ALP、RANKL、RANK水平下降(P0.05)。结论加味阳和汤及其拆方通过提高去卵巢骨质疏松大鼠BMD、BMC,降低骨代谢,改善骨显微结构从而发挥治疗作用,调节OPG/RANKL/RANK轴是可能的机制。     

骨质疏松相关信号通路研究进展

骨代谢过程包括骨形成及骨吸收,当两者间的平衡被打破后便会出现骨硬化或者骨量减少甚至骨质疏松,其具体的分子调节通路不明。现代研究表明,在骨代谢过程中至少存在RANKL/RANK/OPG信号通路、Wnt/β-catenin信号通路、PTH信号通路、PPAR-γ信号通路等,各个通路间还存在交叉。通过分子信号通路,可有效促进骨代谢研究,并开发具有治疗骨质疏松的新药。     

葛根素通过OPG/RANKL及Wnt/β-catenin信号通路介导对来曲唑引起骨流失的保护作用

目的观察葛根素对来曲唑治疗的老年雌性大鼠骨量和骨密度影响,并探索可能的机制。方法 30只24个月龄老年雌性SD大鼠随机分为3组:对照组(CON组);来曲唑组(LQC组):每周给予0.1 mg/kg来曲唑治疗;葛根素+来曲唑组(GGS+LQC组):每天给予50 mg/kg葛根素联合每周给予0.1 mg/kg来曲唑治疗,为期12周,待治疗结束后使用Micro-CT、Masson染色切片、血清学检测以及蛋白质印迹观察治疗效果以及可能的机制。结果治疗12周后,与LQC组相比,GGS+LQC组的大鼠骨小梁数量和骨密度得到明显改善。GGS+LQC组大鼠BMD、BV/TV、Tb.N、Tb.Th和Tb.Sp较CON组明显改善(P0.05)。治疗12周时,GGS+LQC组CTX-1和PINP水平较LQC组显著降低(P0.05),比较差异有统计学意义(P0.05)。和LQC组比较,GGS+LQC组的大鼠OPG/RANKL及Wnt/β-catenin信号通路被激活,OPG、Wnt3α、β-catenin水平显著上升,RANKL水平明显下降,比较差异有统计学意义(P0.05)。结论葛根素通过激活OPG/RANKL及Wnt/β-catenin信号通路逆转来曲唑对老年雌性大鼠骨骼有害作用。     

Wnt/β-catenin、BMP-2/Runx2/Osterix、OPG/RANKL、LGR4/RANKL通路的相关因子在绝经后骨质疏松性骨折中的表达

目的通过检测绝经后骨质疏松性骨折患者(PMOPF组)和对照组中血清、骨组织中因子LRP5、β-catenin、Runx2、Cmyc、Osterix、OPG、RANKL、LGR4水平的表达,分析相关的通路与PMOPF的相关性。方法选取胫骨骨折患者分为对照组、PMOPF组。RNAiso Plus法提取骨组织总RNA,RT-qPCR法检测各因子表达。对照组通过酶联免疫分析方法(ELISA)检测血清各因子水平; PMOPF组按采血时段分A～F组,ELISA检测各因子水平。比较对照组与PMOPF组、PMOPF组中各邻组之间的变化。结果 (1) RT-qPCR法检测PMOPF组骨组织LRP5、β-catenin、Runx2、C-myc、Osterix、OPG、LGR4水平明显下降(P0.05),RANKL水平明显上升(P0.05)。(2) ELISA法检测PMOPF组中A～F组各因子血清水平LRP5、β-catenin、Runx2、Cmyc、Osterix、OPG、LGR4水平明显下降(P0.05),RANKL水平明显上升(P0.05)。LRP5、Runx2在B组最低,β-catenin、Cmyc在C组最低,RANKL在C组最高,Osterix在D组最低,OPG、LGR4在E组最低。结论 Wnt/β-catenin、BMP-2/Runx2/Osterix、OPG/RANKL、LGR4/RANKL通路的相关因子与PMOPF发生关系密切。LRP5、Runx2在骨折3 d内水平降至最低,β-catenin、C-myc在骨折7 d内水平降至最低,反映了其在成骨阶段中的变化一致; Osterix在骨折14 d内水平降至最低,OPG、LGR4在骨折28 d内水平降至最低,可能与PMOPF短期内较难愈合有关; RANKL在骨折7 d内水平升至最高,可能与PMOPF后成骨有所增加有关。     

绝经后骨质疏松与OPG/RANKL/RANK系统的相关研究

骨在整个生命过程都在不断的重建中，骨重建的过程就是破骨细胞(osteoclast，OC)吸收旧骨和成骨细胞(osteoblast，OB)形成新骨的过程，两者紧密偶联，在正常情况下保持动态平衡。当骨重建不平衡时，可导致代谢性骨病如骨质疏松(osteoporosis，OP)等的发生。近年来的研究发现许多激素、细胞因子等，     

OPG/RANKL/RANK基因多态性与绝经后骨质疏松

随着人口老龄化,骨质疏松症患者的增加是目前和将来一段时间内主要的公共健康问题之一,识别并评价每个个体发生骨质疏松的风险并预防性用药是解决这个问题最有效的方法.骨质疏松症是一种多基因疾病,其中遗传因素在骨质疏松的发生中占70%～80%,因此,目前大量研究的目的 是检测哪种基因变异会导致骨质疏松发病率增加.OPG-RANKL-RANK系统作为调节破骨细胞分化成熟的关键环节,理所当然的受到了人们越来越多地关注,但其作为骨质疏松侯选基因的研究还处于起步阶段,许多问题还有待阐明,利用这些基因的SNP筛查绝经后骨质疏松易感人群,对这部分人群进行预防性用药可以更有效的降低绝经后骨质疏松的发生率.     

OPG/RANKL/RANK系统在绝经后 骨质疏松中的调节作用

绝经后骨质疏松（postmenopausal osteoporosis,PMOP )是危及老年妇女健康的一种常见病和多 发病,而在近年在骨质疏松研究中发现的OPG/RANKL/RANK系统是解释骨质疏松形成机制的一个 重大突破。本文对OPG/RANKL/RANK系统及其在雌激素参与下的调节作用作一综述     

骨质疏松症大鼠模型生物力学性能和OPG/RANKL/RANK信号通路研究

摘要：目的 研究针刺对骨质疏松症（osteoporosis，OP）模型大鼠生物力学性能和骨保护素（OPG）/核因子-κB受体活化因子（RANKL） /核因子-κB受体活化因子受体（RANK）信号通路的影响，探讨针刺防治OP的作用机制。方法 选取50只雌性SD大鼠，通过摘除卵巢建立OP大鼠模型，分为假手术组、模型组、针刺低剂量组、针刺高剂量组、阿仑膦酸钠组，每组10只。成功建立模型并对大鼠进行适应性喂养2个月后，连续灌胃给药12周，再进行腹主动脉取血并处死大鼠。通过双能X射线仪测定各组大鼠右侧下肢股骨骨矿含量；用酶联免疫吸附法测定法检测血清钙（Ca2+）、磷（P）和OPG、RANKL、RANK的水平；采用AG-IX万能实验机检测股骨的生物力学性能；采用蛋白质印迹法检测骨组织OPG、RANKL、RANK蛋白的表达。结果 与假手术组比较，模型组大鼠骨组织中骨矿含量、血清Ca2+、P、OPG的表达、股骨组织中OPG蛋白含量和股骨最大载荷、刚度及弹性模量均明显降低（P＜0.01）；血清RANKL和RANK的表达及股骨组织中RANKL、RANK蛋白含量明显升高（P＜0.01）。与模型组比较，针刺低剂量组和针刺高剂量组以及阿仑膦酸钠组上述指标均有明显改善（P<0.05或P<0.01），且针刺的作用具有剂量依赖性（P<0.05或P<0.01）。结论 针刺具有明显的抗OP作用，可能与其改善骨组织生物力学特性以及调控OPG/RANKL/RANK通路有关。     

补肾壮骨中成药对绝经后骨质疏松症治疗机理初探

目的 观察补肾壮骨中成药对绝经后骨质疏松症的疗效,初步探索补肾壮骨中成药治疗绝经后骨质疏松症的作用机制.方法:134例患者随机分为钙剂+活性维生素D治疗组(对照组)及补肾壮骨中成药+钙剂+活性维生素D治疗组(中成药治疗组)两组治疗1年.在第0月、第3月、第6月留取清晨空腹2 h尿检测尿钙/肌酐(Ca/Cr)、尿I型胶原交联C末端肽/肌酐(CTX-I/Cr),第0月、第12月检测骨密度.结果:经治疗1年后,所有患者第0月、第3月、第6月尿Ca/Cr均无明显差异.但中成药治疗组在第3月时尿CTX-I/Cr明显降低(P＜0.01),第12月股骨颈骨密度较基线显著提高(P＜0.01),与对照组第12月股骨颈骨密度比较有显著差异(P＜0.01);腰椎1-4骨密度较基线无明显变化(P＞0.05).尿CTX-I/Cr的变化与股骨颈骨密度的变化呈明显负相关(P＜0.05).而对照组尿CTX-I/Cr、股骨颈/腰椎1-4骨密度变化均无统计学意义.结论:补肾壮骨中成药可以通过填补肾精,滋补肝肾等作用,降低骨吸收,提高骨密度,发挥对绝经后骨质疏松症的治疗作用.其机制可能与抑制破骨细胞骨吸收功能和促进其凋亡有关.     

Genetic variation in the RANKL/RANK/OPG signaling pathway is associated with bone turnover and bone mineral density in men

The aim of this study was to determine if single‐nucleotide polymorphisms (SNPs) in RANKL, RANK, and OPG influence bone turnover and bone mineral density (BMD) in men. Pairwise tag SNPs (r² ≥ 0.8) were selected for RANKL, RANK, and OPG and their 10‐kb flanking regions. Selected tag SNPs plus five SNPs near RANKL and OPG, associated with BMD in published genome‐wide association studies (GWAS), were genotyped in 2653 men aged 40 to 79 years of age recruited for participation in a population‐based study of male aging, the European Male Ageing Study (EMAS). N‐terminal propeptide of type I procollagen (PINP) and C‐terminal cross‐linked telopeptide of type I collagen (CTX‐I) serum levels were measured in all men. BMD at the calcaneus was estimated by quantitative ultrasound (QUS) in all men. Lumbar spine and total‐hip areal BMD (BMD_a) was measured by dual‐energy X‐ray absorptiometry (DXA) in a subsample of 620 men. Multiple OPG, RANK, and RANKL SNPs were associated with bone turnover markers. We also identified a number of SNPs associated with BMD, including rs2073618 in OPG and rs9594759 near RANKL. The minor allele of rs2073618 (C) was associated with higher levels of both PINP (β = 1.83, p = .004) and CTX‐I (β = 17.59, p = 4.74 × 10^?4), and lower lumbar spine BMD_a (β = ?0.02, p = .026). The minor allele of rs9594759 (C) was associated with lower PINP (β = ?1.84, p = .003) and CTX‐I (β = ?27.02, p = 6.06 × 10^?8) and higher ultrasound BMD at the calcaneus (β = 0.01, p = .037). Our findings suggest that genetic variation in the RANKL/RANK/OPG signaling pathway influences bone turnover and BMD in European men. © 2010 American Society for Bone and Mineral Research     

The RANKL/RANK/OPG signaling pathway mediates medial arterial calcification in diabetic Charcot neuroarthropathy

OBJECTIVE

The receptor activator of nuclear factor-κB (RANK), RANK ligand (RANKL), and osteoprotegerin (OPG) signaling pathway (RANKL/RANK/OPG signaling) is implicated in the osteolysis associated with diabetic Charcot neuroarthropathy (CN); however, the links with medial arterial calcification (MAC) seen in people with CN are unclear. This study aimed to investigate the role of RANKL/OPG in MAC in patients with CN.

RESEARCH DESIGN AND METHODS

Enzyme-linked immunosorbent assay and Bio-plex multiarray technology were used to quantify a range of cytokines, including RANKL and OPG in sera from 10 patients with diabetes, 12 patients with CN, and 5 healthy volunteers. Human tibial artery segments were immunohistochemically stained with Alizarin red and human RANKL antibody. Human vascular smooth muscle cells (VSMCs) were also explanted from arterial segments for in vitro studies.

RESULTS

We demonstrate colocalization and upregulation of RANKL expression in areas displaying MAC. Systemic levels of RANKL, OPG, and inflammatory cytokines (interleukin-8, granulocyte colony–stimulating factor) were elevated in those with CN compared with diabetic patients and healthy control subjects. Human VSMCs cultured in CN serum showed accelerated osteoblastic differentiation (alkaline phosphatase activity) and mineralization (alizarin red staining) compared with cells treated with diabetic or control serum (P < 0.05). Coincubation with OPG, the decoy receptor for RANKL, attenuated osteogenic differentiation of VSMCs and was independent of a high calcium-phosphate milieu. The accelerated mineralization induced by RANKL and CN serum correlated with nuclear translocation of nuclear factor-κB, a process abrogated by OPG.

CONCLUSIONS

Our data provide direct evidence that RANKL/RANK/OPG signaling is modulated in patients with CN and plays a role in vascular calcification. This study highlights this pathway as a potential target for intervention.Vascular calcification is a strong independent predictor of cardiovascular mortality (1). In people with diabetes, medial arterial calcification (MAC) has emerged as a strong predictor of lower limb amputation and cardiovascular mortality (2,3). This may be to the result of an increase in arterial stiffness, pulse wave velocity, and systolic blood pressure, ultimately leading to reduced coronary perfusion and ventricular hypertrophy (4). MAC in people with diabetes is more common in those with peripheral neuropathy, who also display increased bone resorption (osteolysis) (5–7), typically seen in Charcot neuroarthropathy (CN). The signaling pathway of the receptor activator of nuclear factor-κB (RANK), RANK ligand (RANKL), and its decoy receptor osteoprotegerin (OPG) has been suggested as the link between vascular and bone metabolism (8,9). In fact, RANKL has been shown to mediate osteolysis in CN by stimulating osteoclastic differentiation of monocytes/macrophages, an effect that is attenuated by OPG, the decoy receptor (10). This has led to nascent theories implicating RANKL/OPG signaling as the potential pathogenetic basis for CN.RANKL exists in two biologically active soluble forms secreted by T cells, endothelial cells, or osteoblasts or proteolytically cleaved from cell surfaces. RANKL binds to its target receptor RANK on cell surfaces (including vascular smooth muscle cells [VSMCs]) to generate multiple intracellular signals that regulate cell differentiation, function, and survival (8,11,12). In the vasculature, RANKL is expressed and upregulated in calcifying vascular cells (13) and enhances the recruitment and infiltration of cells that have been shown to stimulate VSMC mineralization (14).Most of the evidence for a direct role of RANKL/OPG signaling in vascular calcification is derived from animal studies with limited human data. For instance, with the use of VSMCs from rat aorta, RANKL has been shown to increase VSMC calcification via activation of the alternate nuclear factor-κB (NF-κB) pathway (15). However, to enhance translational applications, we extend these data to human VSMCs and use of patient serum.In diabetic CN, there is osteolysis and simultaneous vascular calcification, potentially leading to amputation (16,17). Therefore, the aim of this study was to determine the role of RANKL/OPG signaling in MAC in diabetic CN by using an in vitro model of vascular calcification.     

基于OPG/RANK/RANKL信号轴探讨中医“瘀证”与骨质疏松症之间的关系

近年来,随着中医学的不断发展,中医药在治疗骨质疏松症(osteoporosis,OP)中的应用愈加广泛,然而由于只有单纯的中医理论指导,而缺乏现代科学依据的支撑,故而广受争议。与此同时,OPG/RANK/RANKL信号轴的发现又是现代分子生物学的一大突破。因此,笔者立足于中西医结合的角度,基于中医脏腑亏虚立论,从OPG/RANK/RANKL信号调控机制探讨中医学从"瘀证"论治骨质疏松症的合理性,从而为中医从"瘀"辨治OP以及临床研究提供科学理论依据。