前列腺素E2调节成骨细胞核因子-κB受体激活物配基和护骨素表达的信号通路研究

目的 探讨前列腺素E2(PGE2)对大鼠成骨细胞核因子-κB受体激活物配基(RANKL)和护骨素(OPG)mRNA表达的调节及其信号转导机制.方法 培养大鼠UMR106成骨细胞,采用不同浓度的PGE:和不同的信号通路调节剂干预细胞后,提取细胞总RNA,采用实时荧光定量PCR检测RANKL和OPG mRNA的表达水平.结果 PGE2、福司可林和db-cAMP均促进RANKL mRNA表达和抑制OPG mRNA的表达,RANKL mRNA表达分别为对照组的2.8倍(P=0.002)、2.2倍(P=0.006)和2.1倍(P=0.005).OPG mRNA表达分别为对照组的12%(P<0.01)、85%(P=0.005)和70%(P=0.013).A23187则下调RANKL和OPG表达58%(P=0.002)和53%(P=0.017).KT-5720下调PGE2诱导的RANKL mRNA表达约53%(P<0.01),而白屈菜红碱、维拉帕米、钙调蛋白抑制剂(W7、KN-62和PD98059)则对PGE:诱导的RANKL mRNA表达无明显影响(P>0.05).KT-5720、维拉帕米和W7分别阻断PGE2对OPG mRNA表达的抑制作用47%(P=0.01)、38%(P=0.029)和43%(P<0.01),而KN-62、PD98059和白屈菜红碱则均不影响PGE2对OPG表达的调节(P>0.05).结论 PKA信号通路介导了PGE2诱导的RANKL表达,而PGE2对OPG表达的下调作用则由PKA和Ca2+钙调蛋白信号通路介导.     

淫羊藿总黄酮对去卵巢大鼠骨组织OPG、 OPGL mRNA表达的影响

目的：探讨淫羊藿总黄酮（totalflavoneofepimedium,TFE）治疗骨质疏松症的分子机制,为传统中药的现代化和二次开发提供实验依据。方法：将60只4月龄健康雌性SD大鼠按随机数字表法分为对照组（A组,20只,行假手术处理）,去卵巢纽（OVX组,20只,切除卵巢后不给予淫羊藿处理）,淫羊藿组（TFE纽,20只,切除卵巢后给予淫羊藿灌胃）。所有大鼠术前及术后4周以DEXA骨密度仪检测L4骨密度变化（若BMD下降〉20％,则骨质疏松模型建立）。模型建立后TFE组大鼠给予淫羊藿总黄酮（浓度30mg／ml,10ml／kg,1次／d）灌胃4周。所有大鼠处死前再行DEXA骨密度检测,过量麻醉法处死后取其股骨下部,切片匀浆提取骨组织中RNA,应用逆转录一聚合酶链反应（RT—PCR）技术检测骨组织护骨素（osteoprotegrin,OPG）、护骨素配体（0PGL）mRNA的表达。结果：①TFE组大鼠切除卵巢4周后,腰椎BMD均值降至（0．084±0．020）g／cm^2,降幅〉20％证明骨质疏松模型建立。TFE灌胃4周后其腰椎BMD提高至（0．112±0．009）g／cm^2,与给药前比较有明显改善,差异有统计学意义（P〈0．05）;②TFE组大鼠骨组织中OPGmR—NA的表达较OVX组相比,明显增强,且有统计学差异（P〈0．05）,但对OPGLmRNA表达促进作用不明显,组间无统计学差异（P〉0．05）。结论：TFE是通过促进骨组织中OPGmRNA的表达来抑制破骨细胞的分化和成熟,从而达到治疗骨质疏松症的目的。     

OPG/RANKL/RANK Pathway as a Therapeutic Target in Cancer

Bone metastases play an important role in the morbidity and mortality of patients with malignant disease. Despite therapeutic advances in the treatment of solid organ malignancy such as lung cancer, less development on metastasis interventions has been forthcoming. More recent research has focused on molecular pathway manipulation in the prevention and treatment of metastatic bone disease and associated complications such as bone pain and hypercalcemia. The osteoprotegerin/receptor activator of nuclear factor-кβ ligand/receptor activator of nuclear factor-кβ pathway, which is physiologically involved in bone turnover, has been of considerable interest, and recent promising data have been revealed. In this study, we describe this molecular pathway in terms of its natural physiological function, manipulation for therapeutic benefit, and recent clinical trial results.     

补肾壮骨胶囊含药血清对大鼠成骨细胞增殖及骨保护素mRNA表达的影响

目的:观察补肾壮骨胶囊含药血清对SD大鼠成骨细胞(OB)增殖、骨保护素(OPG)mRNA表达的影响,探讨其防治骨质疏松的机理。方法:将40只3月龄SD雌性大鼠分为补肾壮骨胶囊灌胃组(高、中、低剂量)和空白对照组制备含药血清和空白对照血清;取1天龄SD大鼠颅盖骨,分离、培养成骨细胞(OB),分别加入各实验血清组培养液培养OB,倒置相差显微镜下观察OB生长情况,MTT法测定OB的OD值,RT-PCR检测各组成骨细胞OPGmRNA表达。结果:3-8天时,补肾壮骨胶囊高、中、低含药血清组成骨细胞OD值均高于空白对照组(P<0.05)。各含药血清组成骨细胞OPGmRNA表达均高于空白对照组(P<0.01);补肾壮骨胶囊高、中、低含药血清组间比较,差异无显著意义(P<0.05)。结论:补肾壮骨胶囊含药血清组能促进OB增殖、上调OPGmRNA表达,可能是其防治骨质疏松的机制之一。     

不同浓度葡萄糖对MG63细胞株护骨素和护骨素配体及其相关因子表达的影响

目的：观察不同葡萄糖浓度环境下人成骨肉瘤MG63细胞株护骨素（OPG）、护骨素配体（OPGL）及其相关因子如肿瘤坏死因子相关凋亡诱导配体（TRAIL）、巨噬细胞集落刺激因子（M—CSF）、转化生长因子β（TGF-β）的表达。方法：用RT—PCR法检测基因表达情况。结果：高糖能下调MG63细胞中OPG及TGF—β的表达，上调OPGL、M—CSF和TRAIL的表达。结论：高糖环境可能导致成骨细胞中OPG及TGF—β的表达减少，OPGL、M-CSF和TRAIL等细胞因子的表达增多，使破骨细胞的数目和活性增加，骨吸收增强和骨量丢失，这可能是糖尿病骨质疏松症的一个重要的发病机制。     

米索前列醇对去势后大鼠骨保护素的影响

目的:通过给予去势后大鼠米索前列醇,了解米索前列醇对骨密度及成骨细胞分泌骨保护素 (Osteo protegerin, OPG)的影响。方法:鼠龄90 d的Wistar雌性大鼠共 30 只,分为正常对照组(A组)、去势组(B组)、去势给米索前列醇组(C组),C组去势后第2 d予以2 mg·kg-1·d-1剂量的米索前列醇灌胃,于术后28 d对各组的骨密度进行检测,同时取左侧胫骨干骺端观察骨保护素 mRNA水平的变化。结果: 骨密度检测结果显示 A组最高,C组次之,而B组最低,A组、B组、C组之间差异有显著性(P<0.05);骨保护素3组之间差别有显著性,C组最高,B组次之,A组最低(P<0.05)。结论: 米索前列醇可能通过刺激骨保护素的表达及分泌,来抑制去势后雌性大鼠骨量的丢失。     

RANKL/RANK/OPG系统造成人工关节假体无菌性松动的机制

人工关节假体无菌性松动是影响关节置换术长期疗效的重要因素。许多研究表明,无菌性松动与RANKL/RANK/OPG系统的关系密切。该系统是在破骨细胞分化、激活和凋亡过程中的一个重要信号调节系统,将骨代谢、免疫系统和内分泌系统紧密地联系起来。研究发现,体内多种激素和细胞因子等均直接或间接地调节该系统的表达,调控RANKL、OPG二者之间的平衡,从而介导破骨细胞的分化和功能而达到影响骨代谢的作用。该文就近年RANKL/RANK/OPG系统与人工关节无菌性松动机制的研究进展作一综述。     

Gene therapy with human osteoprotegerin decreases callus remodeling with limited effects on biomechanical properties

Osteoprotegerin (OPG) is a naturally occurring protein, which prevents bone resorption by inhibition of osteoclastogenesis, function, and survival. Therefore, recombinant OPG may be an attractive drug in the treatment of chronic bone resorptive diseases such as osteoporosis. Gene therapy has the potential to achieve long-term treatment by delivering genes of anti-resorptive proteins to the recipient. The effects of OPG gene therapy on fracture healing have not been described previously.

The influence of OPG gene therapy on callus formation, callus tissue structural strength, apparent material properties, and histology of tibia fractures in rats was investigated after 3 weeks and 8 weeks of healing. Intramuscular administration of adeno-associated virus (AAV) vector-mediated OPG resulted in increased levels of OPG in serum of approximately 100 ng/ml throughout the study period. Control animals with fractures received transduction with an AAV reporter gene construct (AAV-enhanced green fluorescent protein (eGFP)), and in this group serum OPG levels remained at baseline (<10 ng/ml). After 3 weeks of healing, AAV-OPG treatment reduced the number of osteoclasts in the callus tissue (33%, P < 0.001). However, AAV-OPG treatment did not influence callus dimensions, callus bone mineral content (BMC), fracture structural strength, or apparent callus tissue material properties. After 8 weeks of healing, AAV-OPG treatment reduced the number of osteoclasts in the callus tissue (31%, P < 0.001) compared with AAV-eGFP fractures. Furthermore, deposition of new woven bone at the fracture line of the original cortical bone was hampered (new woven bone present: in all AAV-eGFP animals, in 41% of AAV-OPG-treated animals, P < 0.001). AAV-OPG treatment also increased callus BMC (18%, P = 0.023) compared with AAV-eGFP fractures. AAV-OPG did not influence callus dimensions, structural strength of the fractures, or ultimate stress, whereas elastic modulus was reduced in the AAV-OPG groups (37%, P = 0.039). The experiment demonstrates that AAV-OPG gene therapy decreases the fracture remodeling, but this does not influence the structural strength of healing fractures.     

Decreased osteoprotegerin and increased bone turnover in young female patients with major depressive disorder and a lifetime history of anorexia nervosa

Low bone mineral density (BMD) is a frequent, often persistent complication in patients with major depressive disorder (MDD) and anorexia nervosa (AN) that increases the risk of pathologic fractures. The pathogenetic process underlying osteopenia in MDD and AN is still unclear, although several factors, including a dysbalance of cytokines, are associated with loss of bone mass. Alterations in the serum levels of cytokines have been observed in patients with MDD, AN, and other psychiatric disorders. Therefore, we examined serum levels of cytokines, markers of bone turnover, and BMD in 13 patients with MDD and a lifetime history of AN. Bone turnover markers (osteocalcin and C-terminal degradation products of type I collagen) and tumor necrosis factor (TNF-) in patients were significantly increased compared with those of the control group. Osteoprotegerin (OPG) in patients was significantly decreased. Eight of 13 patients (62%) displayed osteopenia at the lumbar spine. TNF- correlated significantly with C-terminal degradation products of type I collagen, an osteoclastic marker, but significantly negatively with OPG. Our data suggest that TNF- and OPG may play a role in the pathogenetic process underlying osteopenia in these patients.     

Changes in Osteoprotegerin/RANKL System, Bone Mineral Density, and Bone Biochemicals Markers in Patients with Recent Spinal Cord Injury

This study analyzed the temporal and regional variations in bone loss and explored bone cell activities via biochemical markers during an extended follow-up in patients with spinal cord injury (SCI). In parallel, the possible role of the osteoprotegerin (OPG)/RANKL system in disuse osteoporosis was investigated. Seven male patients with acute and complete SCI (31.3 ± 9.5 years) and 12 able-bodied (AB) men (26.9 ± 4.2 years) participated in the study. Measurements were performed 16, 24, 36, 48, and 71 weeks after injury. At week 16, marked calcium homeostasis disturbance and a concomitant increase in bone resorption markers were observed, reflecting an intense bone degradation process. Resorption activity decreased continuously with time. Contrasting with the great rise in the resorption markers, the bone formation markers showed little variation. During the period of investigation, a loss in bone mineral density (BMD) was demonstrated for the total body (−4.3%), pelvis (−15.7%) and lower limbs (−15.2%), whereas BMD did not change at the lumbar spine, upper limbs, or skull. At all stages, SCI patients had lower serum RANKL levels and higher serum OPG levels than did AB controls, but no significant variation with time was observed for either cytokine. These findings suggest that bone resorption persisted long after SCI and specifically affected BMD at sublesional sites. The marked modification of serum OPG/RANKL levels in SCI patients suggests that this system is affected, in disuse osteoporosis. However, the precise biologic role of the OPG/RANKL system in the bone tissue of SCI patients has yet to be determined.