Microstructure of trabecular bone in a mouse model for down syndrome

Down syndrome (DS) is caused by trisomy of human chromosome 21 (Hsa21) and results in a suite of dysmorphic phenotypes, including effects on the postcranial skeleton and the skull. We have previously demonstrated parallels in the patterns of craniofacial dysmorphology in DS and in the Ts65Dn mouse model for DS. The specific mechanisms underlying the production of these changes in craniofacial shape remain unknown. High‐resolution computed tomography scan data were collected for the presphenoid bone of euploid and aneuploid mice. Three‐dimensional morphometric parameters of trabecular bone were quantified and compared between euploid and aneuploid mice using nonparametric statistical tests. Aneuploid presphenoid bones were smaller than those of their euploid littermates and had lower bone volume fraction and fewer, more rod‐like trabeculae. The differences in cancellous bone structure suggest that bone development, perhaps including bone modeling and remodeling, is affected by aneuploidy. These differences may contribute to the observed dysmorphology of skull and postcranial skeletal phenotypes in DS. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.     

骨质疏松与骨关节炎患者松质骨的显微结构

目的:通过显微计算机断层扫描(micro-computed tomography,Micro-CT)检测股骨头松质骨显微结构,研究骨质疏松与骨关节炎的关系。方法:绝经后妇女骨质疏松性股骨颈骨折和原发性髋关节骨关节炎患者各20名,以Micro-CT扫描检测股骨头软骨下松质骨标本,对2组患者的松质骨显微结构参数进行比较。结果:骨质疏松与骨关节炎松质骨显微结构参数:骨体积分数(bone volume fraction,BV/TV)、骨表面积体积比(bone surface/bone volume,BS/BV)、骨小梁厚度(trabecular thickness,Tb.Th)、骨小梁间距(trabecular separation,Tb.Sp)、结构模型指数(structure model index,SMI)、连接密度(connectivity density,Conn.D)比较差异有统计学意义,BV/TV,SMI与Tb.N,TbTh,BS/BV,Tb.Sp呈相关关系。结论:骨质疏松与骨关节炎的显微结构存在差异,这些差异可能导致相反的骨缺陷;BV/TV,SMI是评价显微结构参数的2个重要指标。     

Examination of osteoarthritis and subchondral bone alterations within the stifle joint of an ovariectomised ovine model

The exact relationship between osteoporosis and osteoarthritis is still a matter for debate for many. The ovariectomised ewe is frequently used as a model for osteoporosis, resulting in significant alterations in bone morphometry and turnover in both trabecular and subchondral bone after 1 year. This study examines whether ovariectomy has any impact on development of osteoarthritis within the ovine stifle joint at the same time point. In addition, we investigate whether there are any significant correlations present between articular cartilage degeneration and alterations in microstructural parameters or turnover rates in the underlying bone. Twenty‐two sheep were examined in this study; 10 of the sheep underwent ovariectomy and 12 were kept as controls. Five distinctive fluorochrome dyes were administered intravenously at 12‐week intervals to both groups, to label sites of bone turnover. All animals were then sacrificed 12 months postoperatively. Although most specimens showed some evidence of osteoarthritis, no measurable difference between the two study groups was detected. Osteoarthritis was associated with a thinning of the subchondral plate, specifically the subchondral cortical bone; however, whereas previous studies have suggested a link between trabecular thinning and osteoarthritis, this was not confirmed. No correlation was found between osteoarthritis and bone turnover rates of either the subchondral trabecular bone or bone plate. In conclusion, despite the fact that ovariectomy results in marked morphological and structural changes in the ovine stifle joint at 1‐year postoperatively, no evidence was found to suggest that it plays a direct role in the aetiology of osteoarthritis.     

Subchondral bone changes and chondrogenic capacity of progenitor cells from subchondral bone in the collagenase-induced temporomandibular joints osteoarthritis rabbit model

Purpose: The goals of this study were to characterize subchondral bone changes, and to determine biological activity characteristics of progenitor cell populations from subchondral bone in the collagenase-induced temporomandibular joint osteoarthritis (TMJOA) rabbit model. Greater understanding of such pathological changes occurring in TMJOA samples is critical in the future treatment modalities regarding cartilage protection and repair. Furthermore, the use of progenitor cell populations in various cartilage regeneration strategies proves to be a fruitful avenue for research and clinical applications. Materials and methods: Bone remodeling and anabolic activity of subchondral bone was evaluated by hematoxylin-eosin (H&E), Alcian blue-periodic acid-Schiff (AB-PAS) staining and immuohistochemical staining. The biological activity characteristics of progenitor cells were assessed by expressions of collagen type II, CD44, SOX-9 and MMP-9 by immunohistochemistry and Western blot analysis. Results: In most of the specimens, cartilage of the digested area displayed a reaction characterized by thickening of the cartilage cellular structure with retraction structure formation in the subchondral bone. Most of the specimens focuses on chondroid metaplasia were observed in the subchondral bone, promoting its remodeling, which could develop to endochondral ossification and increasing subchondral bone size. Meanwhile, immunohistochemistry analysis revealed that CD44 expressions in subchondral bone were most significantly increased in TMJOA at 2 weeks group (P < 0.01). And, at 4, 6 and 8 weeks groups, the osteochondral junction had completely disappeared by active subchondral bone remodeling, and collagen type II, CD44, SOX-9 and MMP-9 expressions in active subchondral bone region were significantly increased in TMJOA (P < 0.05). In addition, western blot analysis revealed that CD44 expression significantly emerged in subchondral bone region at 2 weeks group (P < 0.01). Meanwhile, SOX-9 expression emerged in all group, and the intensity was increased in the experimental groups (P < 0.05). Conclusion: Our results suggest that the beneficial activation of progenitor cells and bone marrow stem cells in subchondral bone at early stage of TMJOA played an important role on renovation and remodeling of subchondral bone.     

Subchondral bone morphology in the metacarpus of racehorses in training changes with distance from the articular surface but not with age

The repetitive large loads generated during high‐speed training and racing commonly cause subchondral bone injuries in the metacarpal condyles of racehorses. Adaptive bone modelling leads to focal sclerosis at the site of highest loading in the palmar aspect of the metacarpal condyles. Information on whether and how adaptive modelling of subchondral bone changes during the career of a racehorse is sparse. The aim of this cross‐sectional study was to describe the changes in subchondral bone micromorphology in the area of highest loading in the palmar aspect of the metacarpal condyle in thoroughbred racehorses as a function of age and training. Bone morphology parameters derived from micro‐CT images were evaluated using principal component analysis and mixed‐effects linear regression models. The largest differences in micromorphology were observed in untrained horses between the age of 16 and 20 months. Age and duration of a training period had no influence on tissue mineral density, bone volume fraction or number and area of closed pores to a depth of 5.1 mm from the articular surface in 2‐ to 4‐year‐old racehorses in training. Horses with subchondral bone injuries had more pores in cross‐section compared with horses without subchondral bone injuries. Differences in bone volume fraction were due to the volume of less mineralised bone. Tissue mineral density increased and bone volume fraction decreased with increasing distance from the articular surface up to 5.1 mm from the articular surface. Further research is required to elucidate the biomechanical and pathophysiological consequences of these gradients of micromorphological parameters in the subchondral bone.     

Recent advances in the understanding of molecular mechanisms of cartilage degeneration,synovitis and subchondral bone changes in osteoarthritis

Osteoarthritis (OA), the most common form of degenerative joint disease, is linked to high morbidity. It is predicted to be the single greatest cause of disability in the general population by 2030. The development of disease-modifying therapy for OA currently face great obstacle mainly because the onset and development of the disease involve complex molecular mechanisms. In this review, we will comprehensively summarize biological and pathological mechanisms of three key aspects: degeneration of articular cartilage, synovial immunopathogenesis, and changes in subchondral bone. For each tissue, we will focus on the molecular receptors, cytokines, peptidases, related cell, and signal pathways. Agents that specifically block mechanisms involved in synovial inflammation, degeneration of articular cartilage, and subchondral bone remodeling can potentially be exploited to produce targeted therapy for OA. Such new comprehensive agents will benefit affected patients and bring exciting new hope for the treatment of OA.     

膝骨性关节炎患者胫骨软骨下骨超微结构改变的CT评价

文题释义： 膝骨性关节炎：是一种以渐进性的关节损伤为主要特征,并最终导致患者关节疼痛甚至残疾,极大地降低患者生活质量。 CT：利用精确准直的X射线束、γ射线、超声波等,与灵敏度极高的探测器一同围绕人体的某一部位作一个接一个的断面扫描,具有扫描时间快、图像清晰等特点。 背景：软骨下骨的改变在膝骨性关节炎的作用得到了越来越多的重视,但是既往研究主要以动物为观察对象,由于动物与人存在差异,因而直接在人体关节内获得相关数据是非常必要的。 目的：通过CT技术评价非膝骨性关节炎患者与膝骨性关节炎患者软骨下骨板及软骨下骨超微结构的区别,来探讨软骨下骨在膝骨性关节炎疾病的发生和发展中的作用。 方法：于2016年7月至2018年7月在郑州市骨科医院影像科就诊患者中,收集30例膝骨性关节炎患者(膝骨性关节炎组)及30例非膝骨性关节炎患者(非膝骨性关节炎组)的CT扫描数据,使用MIMICS软件比较2组胫骨平台内外侧软骨下骨板以及软骨下骨小梁超微结构。试验于2016-06-10经郑州市骨科医院伦理委员会审批通过,审批号为2016医院伦审第004号。 结果与结论：①与非膝骨性关节炎组相比,膝骨性关节炎组软骨下骨板在外侧部位和内侧部位骨密度都明显增加,孔隙率则出现显著的下降,而软骨下骨板厚度内侧部分较非膝骨性关节炎组显著增厚;②膝骨性关节炎软骨下骨小梁同样存在明显变化,表现为膝骨性关节炎组内外侧软骨下骨骨小梁厚度较非膝骨性关节炎组均明显增加,同时内侧松质骨分离度也较非膝骨性关节炎组低;膝骨性关节炎组结构模型指数和连接密度值低于非膝骨性关节炎组;③结果表明,膝骨性关节炎患者胫骨软骨下骨板及软骨下骨松质骨的改变主要在于超微结构稳态的破坏,这一改变可能是膝骨性关节炎发病原因之一。 ORCID: 0000-0002-9805-3084(白玉) 中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程     

Contrast-enhanced micro-computed tomography of compartment and time-dependent changes in femoral cartilage and subchondral plate in a murine model of osteoarthritis

A lack of understanding of the mechanisms underlying osteoarthritis (OA) progression limits the development of effective long-term treatments. Quantitatively tracking spatiotemporal patterns of cartilage and bone degeneration is critical for assessment of more appropriately targeted OA therapies. In this study, we use contrast-enhanced micro-computed tomography (μCT) to establish a timeline of subchondral plate (SCP) and cartilage changes in the murine femur after destabilization of the medial meniscus (DMM). We performed DMM or sham surgery in 10–12-week-old male C57Bl/6J mice. Femora were imaged using μCT after 0, 2, 4, or 8 weeks. Cartilage-optimized scans were performed after immersion in contrast agent CA4+. Bone mineral density distribution (BMDD), cartilage attenuation, SCP, and cartilage thickness and volume were measured, including lateral and medial femoral condyle and patellar groove compartments. As early as 2 weeks post-DMM, cartilage thickness significantly increased and cartilage attenuation, SCP volume, and BMDD mean significantly decreased. Trends in cartilage and SCP metrics within each joint compartment reflected those seen in global measurements, and both BMDD and SCP thickness were consistently greater in the lateral and medial condyles than the patellar groove. Sham surgery also resulted in significant changes to SCP and cartilage metrics, highlighting a potential limitation of using surgical models to study tissue morphology or composition changes during OA progression. Contrast-enhanced μCT analysis is an effective tool to monitor changes in morphology and composition of cartilage, and when combined with bone-optimized μCT, can be used to assess the progression of degenerative changes after joint injury.     

Microstructural changes in cartilage and bone related to repetitive overloading in an equine athlete model

The palmar aspect of the third metacarpal (MC3) condyle of equine athletes is known to be subjected to repetitive overloading that can lead to the accumulation of joint tissue damage, degeneration, and stress fractures, some of which result in catastrophic failure. However, there is still a need to understand at a detailed microstructural level how this damage progresses in the context of the wider joint tissue complex, i.e. the articular surface, the hyaline and calcified cartilage, and the subchondral bone. MC3 bones from non‐fractured joints were obtained from the right forelimbs of 16 Thoroughbred racehorses varying in age between 3 and 8 years, with documented histories of active race training. Detailed microstructural analysis of two clinically important sites, the parasagittal grooves and the mid‐condylar regions, identified extensive levels of microdamage in the calcified cartilage and subchondral bone concealed beneath outwardly intact hyaline cartilage. The study shows a progression in microdamage severity, commencing with mild hard‐tissue microcracking in younger animals and escalating to severe subchondral bone collapse and lesion formation in the hyaline cartilage with increasing age and thus athletic activity. The presence of a clearly distinguishable fibrous tissue layer at the articular surface immediately above sites of severe subchondral collapse suggested a limited reparative response in the hyaline cartilage.     

Age-related mineralization heterogeneity changes in trabecular bone of the proximal femur

Although there is extensive documentation in the literature regarding the importance of trabecular bone for proximal femoral integrity and fracture resistance, there remain gaps in our understanding of the basic mineral changes that may occur in trabecular bone attributable to aging. It is unclear what age-related changes take place in the trabecular bone of the proximal femur, a common fracture site in the elderly. It has been suggested that some explanation for conflicting reports on cancellous bone may be found at a microscopic level. The goal of this study was to document age-related changes in micromineralization in the proximal femur of Caucasian females using backscattered electron imaging technology. Proximal femurs were obtained from 11 young and 11 elderly females. Sections of bone from the superior and inferior neck and superior and inferior trochanter were analyzed in a scanning electron microscope using the backscatter technique to determine ash percent. Mean ash percent did not change with age in any of the four regions (P > 0.05). However, while the mean ash percent did not change, there was a dramatic increase in variability elderly age group and loss of mineral heterogeneity. This indicates that there are subpopulations with higher or lower ash percents than the mean in the elderly study group in this investigation. While variance changed dramatically, variance within individuals did not change significantly with age (P > 0.05). The results of this study suggest that changes in micromineralization may occur within an individual, adding a possible new dimension to our understanding of fracture risk in the elderly. Future studies should examine a longer population base to confirm this observation.     

股骨近端主张力骨小梁生物力学特性

目的 研究股骨近端主张力骨小梁的生物力学性能,为解释股骨颈骨折后股骨头坏死的发生原因提供实验依据.方法 取8个正常国人(45 ～60岁)尸体股骨,排除畸形、骨折等病变.将近端主张力骨小梁系统从外侧到内侧分成3个区,在每个区内沿主张力小梁方向及与其垂直方向切取骨小梁试件,并分别在EnduraTEC ELF3200生物力学...     

Development of a microcomputed tomography scoring system to characterize disease progression in the Hartley guinea pig model of spontaneous osteoarthritis

Aim: There is potential discrepancy between human and laboratory animal studies of osteoarthritis (OA), as radiographic assessment is the hallmark of the former and histopathology the standard for the latter. This suggests a need to evaluate OA in animal models in a manner similar to that utilized in people. Our study aimed to develop a whole joint grading scheme for microcomputed tomography (microCT) images in Hartley guinea pigs, a strain that recapitulates joint changes highlighted in human spontaneous OA. Materials and Methods: Knees from animals aged 2, 3, 5, 9, and 15 months were evaluated via whole joint microCT and standard histologic scoring. Quantitative microCT parameters, such as bone volume/total volume were also collected. Results: Both whole joint microCT and histologic scores increased with advancing age and showed strong correlation (r = 0.89. p < 0.0001). Histologic scores, which focus on cartilage changes, increased progressively with age. Whole joint microCT scores, which characterize bony changes, followed a stepwise pattern: scores increased between 3 and 5 months of age, stayed consistent between 5 and 9 months, and worsened again between 9 and 15 months. Conclusions: This work provides data that advocates the use of a whole joint microCT scoring system in guinea pig studies of OA, as it provides important information regarding bony changes that occur at a different rate than articular cartilage changes. This grading scheme, in conjunction with histology and quantitative microCT measurements, may enhance the translational value of this animal model as it pertains to human work.     

股骨近端主压力骨小梁生物力学特性

目的股骨头坏死是一种常见病,导致其发病的原因有很多,其中股骨颈骨折后股骨头坏死的原因尚不清楚,机制不明,由于其局部解剖结构特殊,根据其内部结构特点,对骨小梁结构进行研究,为解释股骨颈骨折后股骨头坏死的发生原因提供实验依据。方法对正常中国人(45～60岁)尸体股骨近端主压力骨小梁系统从上到下分成3个区,分别在Endura TEC ELF3200生物力学材料动态力学性能测试系统上,从主压力骨小梁方向及与其垂直方向上进行拉伸、压缩性能实验研究。结果得出了股骨近端主压力骨小梁系统3个区在主压力骨小梁系统方向及与其垂直方向的压缩、拉伸屈服强度、极限强度、弹性模量等测试指标的实验结果。从上到下3个区的弹性模量等生物力学性能依次递增,主压力方向的压缩生物力学性能要明显高于拉伸生物力学性能,并且生物力学性能在主压力系统方向及与其垂直方向有明显差异。结论股骨近端主压力骨小梁的主要力学性能是承受压应力,并且具有明显的各向异性。     

The phytoestrogen genistein prevents trabecular bone loss and affects thyroid follicular cells in a male rat model of osteoporosis

As a major phytoestrogen of soy, genistein effectively prevents bone loss in both humans and rat models of osteoporosis. However, although the bone‐sparing effects of genistein are achieved directly through estrogen receptors, its mode of action on bone by modulation of other endocrine functions is not entirely clear. Thus, thyroid hormones and calcitonin (CT ) have an essential influence on bone metabolism. Besides its action on bones, in this study we examined the effect of genistein on the activity of two different endocrine cell populations, thyroid follicular and C‐cells. Fifteen‐month‐old Wistar rats were either bilaterally orchidectomized (Orx) or sham‐operated (SO ). Two weeks after surgery, half of the Orx rats were treated chronically with 30 mg kg^?1 b.w. genistein (Orx + G) subcutaneously (s.c.) every day for 3 weeks, while the remaining Orx rats and the SO rats were given the same volume of sterile olive oil to serve as controls. For histomorphometrical analysis of the trabecular bone microarchitecture an ImageJ public domain image processing programme was used. Thyroid sections were analysed histologically and stereologically after visualization of follicular and C‐cells by immunohistochemical staining for thyroglobulin and CT . Thyroid follicular epithelium, interstitium, colloid and CT ‐immunopositive C‐cells were examined morphometrically. Serum concentrations of osteocalcin (OC ), triiodothyronine (T₃), thyroxine (T₄) and CT were determined as well as urinary calcium (Ca²⁺) concentrations. Genistein treatment significantly increased cancellous bone area (B.Ar), trabecular thickness (TbTh) and trabecular number (TbN) (P  < 0.05), but trabecular separation (Tb.Sp) was decreased (P  < 0.05) compared with control Orx rats. In the thyroid, genistein treatment significantly elevated the relative volume density (Vv) of the follicular cells (P  < 0.05) compared with Orx, whereas Vv of the colloid was lower (P  < 0.05) than in the Orx. Evaluation of the biochemical parameters showed significant reductions in serum OC , T₃, T₄ and urinary Ca²⁺ concentrations (P  < 0.05), compared with Orx rats. These data indicate that genistein treatment improves the trabecular microarchitecture of proximal tibia, induces histomorphometrical changes in thyroid glands, and decreases circulating thyroid hormone levels in orchidectomized rat model of male osteoporosis.     

淫羊藿苷治疗骨性关节炎过程中对关节软骨、软骨下骨、滑膜等影响的机制

文题释义： 淫羊藿苷：为淫羊藿干燥茎叶的提取物,呈淡黄色针状结晶粉末, 相对分子质量为676.65, 属黄铜类化合物,现代药理学研究发现其具有很强的生物活性, 对骨组织、免疫系统、肿瘤组织、神经系统、生殖系统、内分泌系统和心血管系统等具有显著作用。 滑膜：是关节囊的内层。滑膜呈淡红色,平滑闪光,薄而柔润,由疏松结缔组织组成,其功能是制造和调节滑液等。滑膜直接附着于关节软骨的边缘并向内贴附在关节囊内的非关节区域,覆盖在关节囊、关节内韧带、骨与肌腱表面。滑膜分泌滑液,在关节活动中起重要作用。背景：淫羊藿苷是具有补肾强筋健骨功效的淫羊藿的主要有效成分,近年来大量的研究发现淫羊藿苷在治疗骨性关节炎方面有着显著作用。 目的：综述淫羊藿苷治疗骨性关节炎的分子机制研究进展。 方法：第一作者应用计算机以“Icariin、Osteoarthritis、Cartilage、Subchondral bone、Synovial membrane 、Synovium、Inflammation”及“淫羊藿苷、骨关节炎、骨性关节炎、软骨、软骨下骨、滑膜、炎症”作为主题词检索PubMed、中国知网、万方、维普等数据库相关文献,按入选标准及排除标准进行筛选,最终纳入42篇文献进行分析。 结果与结论：淫羊藿苷通过促进骨髓间充质干细胞的成软骨分化及增强软骨细胞和成骨细胞的增殖,抑制软骨细胞外基质的降解、降低破骨细胞的活性和减轻炎症因子所致的滑膜炎症反应来有效的治疗骨性关节炎。但其最佳有效剂量及浓度安全性仍需要大量实验研究,目前绝大部分实验仍停留在动物及组织细胞等基础实验,尚需要大量临床研究,继续完善其具体机制,以期为淫羊藿苷治疗骨关节炎提供循证医学证据。ORCID:0000-0002-2013-743X(余绍涌)中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

骨关节炎软骨下骨中视网膜母细胞瘤RB1-诱导卷曲蛋白1的表达及作用

文题释义：视网膜母细胞瘤RB1-诱导卷曲蛋白1(RB1-inducible coiled-coil 1,RB1CC1)：是一种相对分子质量为200的FAK家族相互作用蛋白,最初通过酵母双杂交筛选鉴定为Pyk2相互作用蛋白,并可作为RB1基因的潜在调节因子,参与肿瘤细胞的周期调控。RB1CC1多在心脏、睾丸、肌肉骨骼以及小鼠胚胎等组织中大量表达,对细胞的生长、分化、凋亡和自噬起到重要的调控作用。 骨涎蛋白：是一种由成骨细胞、破骨细胞合成的磷酸化糖蛋白,相对分子质量为75,含有约300个氨基酸。在骨组织中大量表达,可特异性定位于矿化的骨组织内,参与成骨细胞和破骨细胞的骨代谢活动,是成骨细胞矿化成熟的标志。骨涎蛋白的RGD序列基因可与血管内皮细胞的整合素结合,从而引导软骨组织内血管形成。 背景：骨关节炎以关节软骨的退变和软骨下骨的重建为主要病理特征。骨关节炎的具体发病机制目前仍未清楚,大部分研究以软骨与软骨下骨为主要切入点,探索疾病过程中的分子机制和信号通路变化,为骨关节炎的诊断与治疗提供新的生物靶点和研究方向。 目的：探讨在骨关节炎进程中软骨下骨RB1CC1的表达情况。 方法：8周龄C57小鼠随机分为实验组和假手术组,实验组又随机分为4周和8周2个亚组。实验组小鼠行右侧膝关节内侧半月板胫骨韧带切除,游离内侧半月板,诱导骨关节炎;假手术组小鼠则仅切开关节囊而不行内侧韧带切除和半月板游离。实验方案于2017-12-13经南方医科大学第三附属医院动物实验伦理委员会批准,批准号为No.44007200038731。 结果与结论：与假手术组相比,实验组骨关节炎RSI评分均显著升高,关节软骨面Ⅱ型胶原表达降低,软骨下骨中的RB1CC1表达逐渐升高,RB1CC1与成骨相关指标BSP2的表达趋势有一致性;提示随着骨关节炎进程的发展,软骨下骨的RB1CC1表达逐渐增多,可能与促进软骨下骨增生及重塑有关。 ORCID: 0000-0002-2838-3707(蔡道章) 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

Ontogenetic structural and material variations in ovine calcanei: A model for interpreting bone adaptation

Experimental models are needed for resolving relative influences of genetic, epigenetic, and nonheritable functionally induced (extragenetic) factors in the emergence of developmental adaptations in limb bones of larger mammals. We examined regional/ontogenetic morphologic variations in sheep calcanei, which exhibit marked heterogeneity in structural and material organization by skeletal maturity. Cross‐sections and lateral radiographs of an ontogenetic series of domesticated sheep calcanei (fetal to adult) were examined for variations in biomechanically important structural (cortical thickness and trabecular architecture) and material (percent ash and predominant collagen fiber orientation) characteristics. Results showed delayed development of variations in cortical thickness and collagen fiber orientation, which correlate with extragenetic factors, including compression/tension strains of habitual bending in respective dorsal/plantar cortices and load‐related thresholds for modeling/remodeling activities. In contrast, the appearance of trabecular arches in utero suggests strong genetic/epigenetic influences. These stark spatial/temporal variations in sheep calcanei provide a compelling model for investigating causal mechanisms that mediate this construction. In view of these findings, it is also suggested that the conventional distinction between genetic and epigenetic factors in limb bone development be expanded into three categories: genetic, epigenetic, and extragenetic factors. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.     

软骨下骨局部注射常山酮抑制转化生长因子β1信号通路缓解犬骨关节炎

文题释义： Micro-CT：即微型计算机断层扫描,遵循的是与用于医疗的计算机断层扫描相同的原理,但可提供更高分辨率,Micro-CT和高分辨率外周定量计算机断层扫描系统是目前最有用的且拥有高分辨率的骨小梁和皮质骨超微结构成像,目前用于评估骨形态特征,作为传统组织学分析的补充替代方案。 X型胶原蛋白α1链(COL10A1)：为X型胶原蛋白的特异性裂解片段,X型胶原蛋白是软骨细胞肥大分化的典型标志,在骨关节炎进展过程中,软骨细胞肥大及其合成的促炎细胞因子助软骨破坏。 背景：研究表明随着破骨细胞骨吸收的增加,过度激活了的转化生长因子β1使骨吸收和骨形成解偶联,最终导致骨关节炎动物模型中软骨下骨的硬化表型,且可通过抑制转化生长因子β1信号传导减弱骨关节炎的进展。 目的：检测前十字韧带横切比格犬骨关节炎模型中局部注射常山酮是否可以延缓骨关节炎进展。 方法：将18只雄性比格犬分为假手术(对照组)、骨性关节炎组及治疗组,后两组通过前十字韧带横切构建骨关节炎模型,治疗组造模后于软骨下骨局部注射常山酮37.8 ng。在造模术后4,8,12,16周纵向测量血清Ⅱ型胶原C端肽(CTX-Ⅱ)和X型胶原蛋白α1链血清标志物的水平;术后16周Micro-CT扫描观察软骨下骨微结构;番红固绿染色及OARSI-Modified Manking评分评估关节软骨退变程度;免疫组织化学染色对比转化生长因子β1、基质金属蛋白酶13的表达情况。实验方案经新疆医科大学第一附属医院动物实验伦理委员会批准(批准号为IACUC20160304-07)。 结果与结论：①造模后8,12周,骨关节炎组X型胶原蛋白α1链水平高于治疗组和对照组(均P < 0.01);②造模后8,12,16周,骨关节炎组CTX-Ⅱ水平均高于对照组和治疗组(均P < 0.05);③骨关节炎组软骨下骨的骨体积分数较治疗组和对照组增加,骨小梁分离度降低,骨小梁模式因子减小(均P < 0.05);④骨关节炎组OARSI-Modified Manking评分较对照组和治疗组更高(均P < 0.01);⑤骨关节炎组基质金属蛋白酶13及转化生长因子β1的表达量较对照组和治疗组更高(均P < 0.01);⑥对照组与治疗组上述各指标比较差异均无显著性意义(均P > 0.05);⑦结果说明,局部注射常山酮可通过抑制软骨下骨中异常升高的转化生长因子β1,阻断异常骨重塑来减轻前十字韧带横切诱导的骨关节炎,表明这可能是骨关节炎的一种新的治疗选择。 ORCID: 0000-0003-1388-5541(任姜栋) 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程