The role of muscles in joint adaptation and degeneration

Background Muscles are the primary contributors to joint loading. Loading is typically associated with the onset and progression of joint degeneration, and in turn, joint degeneration is known to affect negatively the control of muscle forces and co-ordination patterns. Nevertheless, the role of muscles in joint adaptation and degeneration has been largely ignored. Here, we review some of our research on the in vivo changes in muscular forces and joint loading in animal models of osteoarthritis and in patients with joint injury and disease. We attempt to emphasize the close dependence of muscle forces, joint loading and degeneration and, vice versa, try to point out how joint degeneration affects muscle forces and joint loading.Material and methods We measured the forces and electromyographic signals in normal and anterior cruciate ligament transected feline knees and measured (1) a consistent decrease in the knee extensor and ankle extensor muscle forces for weeks following intervention; (2) a corresponding decrease in the static and dynamic external ground reaction forces; and (3) a change in the electromyographic signals (in terms of the firing patterns of individual muscles and of the co-ordination of extensors and flexors during locomotion). We introduced results on the biosynthetic response of articular cartilage to controlled, in vivo, loading and discuss preliminary results from an experimental animal model of muscle weakness. In contrast to much of the published literature, loading, in our case, is introduced by controlled nerve stimulation and the corresponding muscular forces that load the joint in its in vivo configuration.Results We found that short-term loading (30–60 min) in the cat knee produces distinct up-regulation of mRNA of specific metalloproteinases (MMPs) and some of the MMP inhibitors. In our newly developed muscle-weakness model, we confirmed that controlled Botox injections in the rabbit knee extensor muscles cause a 60–80% decrease in muscle force, and that these changes in muscle force are associated with changes in the external ground reaction forces, and most importantly, that muscle weakness seems to be associated with degeneration of the knee in the absence of joint instability or any other intervention.Conclusion From the results of our research, we conclude that muscle health and muscle rehabilitation are key components for the successful prevention of, and recovery from, joint injury and disease.     

退变兔椎间盘软骨终板细胞培养及其形态学和生物学特征

目的观察研究兔椎间盘软骨终板的细胞形态及表征,利用正常动物的体细胞传代培养发生功能退变的原理,制作软骨终板细胞体外培养的退变模型。方法酶消化法培养兔椎间盘软骨终板细胞,并用HE和甲苯蓝染色,进行光镜观察;使用免疫组织化学法检测特征性Ⅱ型胶原表达情况,与同种动物不同部位的软骨细胞做对照。结果镜下观察,HE染色见细胞呈多角形,核嗜碱性,圆形或椭圆形,有时见双核,胞浆内可见空泡,有弱嗜酸性。甲苯胺蓝染色可见胞浆有紫红色和红色异染出现。原代细胞与传代细胞之间,形态结构无明显差异,但多次传代后(4代),细胞则逐渐失去其原有形态,变为短梭型细胞,失去分化特性,表达Ⅱ型胶原的量逐渐减少。软骨关节细胞与终板细胞形态学相似。结论本研究提示(1)软骨终板细胞可表达其特征性产物蛋白多糖和Ⅱ型胶原;(2)软骨终板细胞在传代培养时有逐渐退变,失去分化特性的特点;(3)在应用平面培养体系时应选用前3代细胞进行实验。以上几点均为椎间盘软骨终板退变机理研究提供了细胞学基础。     

腰椎椎间盘退行性变动物模型建立方法的研究进展

腰痛是目前全球首位致残疾病,给患者、家庭和社会造成极大的痛苦和沉重的负担.与增龄有关的椎间盘退行性变(IDD)是腰痛的最主要原因.随着工作与生活节奏的加快,IDD 呈现年轻化的趋势.建立符合IDD 规律、成功率高、可重复性好、操作简单、成本低且适合医学研究的IDD 动物模型,对明确腰椎IDD 的发生机制及开展防治工作具...     

自噬在张力诱导终板软骨细胞退变过程中的变化

 目的 探讨自噬在张力诱导终板软骨细胞退变过程中的变化及作用。方法 取10只清洁级SD大鼠腰椎终板软骨进行细胞培养。对P1代终板软骨细胞分别加载间歇循环张力（10%伸长率,0.5 Hz）0 h、3 h、12 h、24 h、48 h。以倒置相差显微镜观察细胞形态学变化,实时PCR与蛋白印迹法检测软骨标志基因Ⅱ型胶原、转录因子SOX-9及蛋白多糖转录因子、Beclin-1和LC3基因表达的变化,以单丹磺酰戊二胺染色观察自噬小体。MTT（3-2,5-二苯基四氮唑溴盐染色）法检测3-甲基腺嘌呤（自噬抑制剂）刺激前后的细胞存活率。结果 间歇循环张力诱导后0 h组与3 h组为正常终板软骨细胞形态,呈多角形;12 h组略呈不规则形;24 h组和48 h组呈梭形改变。实时PCR显示24 h组和48 h组中Ⅱ型胶原、转录因子SOX-9及蛋白多糖的表达量降低;自噬相关基因LC3和Beclin-1表达量呈时间依赖性增加。单丹磺酰戊二胺染色显示24 h组和48 h组自噬发生率呈时间依赖性增加。MTT结果显示细胞存活率呈降低趋势;添加3-甲基腺嘌呤刺激后细胞活性减弱、存活率降低。结论 间歇循环张力刺激下终板软骨细胞表型逐渐丧失;自噬相关基因LC3与Beclin-1表达明显上调,但细胞活性降低;抑制自噬水平可降低细胞存活率,提示自噬参与了间歇循环张力诱导的终板软骨细胞退变过程。     

Detection and analysis of cartilage degeneration by spatially resolved streaming potentials.

Cartilage molecular changes in osteoarthritis are most commonly related to the degradation and loss of proteoglycan and collagen fibrils of the extracellular matrix, which directly influence tissue stiffness and compression-generated streaming potentials. In this study, we evaluated the potential of a new technique, spatially resolved mapping of streaming potentials, to non-destructively indicate cartilage health or degeneration. Matched pairs of bovine cartilage/bone explant disks were cultured for 11 days in a serum free medium with and without interleukin-lalpha (IL-1alpha). The electromechanical properties (static stiffness, dynamic stiffness and streaming potentials) of cartilage disks were measured during unconfined compression using a mechanical tester coupled with a linear array of eight 50 microm diameter platinum-iridium microelectrodes. After 11 days of culture, the proteoglycan content of IL-1alpha treated disks was significantly reduced and the denatured and cleaved collagen content was increased compared to control disks. These biochemical alterations were concomitant with the reductions in the amplitudes of the static stiffness, the dynamic stiffness and the streaming potential profile as well as changes in the shape of the streaming potential profile. We found that spatial mapping of streaming potentials presents several advantages for the development of a clinical instrument to evaluate the degeneration of articular cartilage.     

关节滑液3B3表位检测对软骨早期退变的诊断价值

[目的]骨性关节炎、髌骨软化症病人膝关节滑液中3B3表位含量是否与软骨退变程度相关。[方法]作者改良了竞争性ELISA检测关节滑液3B3表位的方法。抽吸71例膝骨关节炎、57例髌骨软化症病人及10例正常人志愿者的膝关节滑液，用该方法检测关节滑液中3B3表位含量，比较各组之间的差异。[结果]骨性关节炎组及髌骨软化组病人膝关节滑液中3B3表位均比正常人对照明显升高（P〈0．05），而且骨关节炎Ⅱ级关节软骨退变时关节滑液中3B3表位含量明显比Ⅳ级关节软骨退变增高（P〈0．01），而髌骨软骨软化患者Ⅱ、Ⅲ、Ⅳ级软骨退变各组间无明显差异（P〉0．05）。[结论]检测关节滑液中3B3表位含量具有诊断关节软骨退变的价值，尤其适用于骨性关节炎软骨早期退变（Ⅱ级）的诊断。     

Lateral ligament injury of the ankle and associated articular cartilage degeneration in the talocrural joint: anatomic study using elderly cadavers

We investigated degenerative changes (DCs) of the articular cartilage using 33 cadaveric talocrural joints with anterior talofibular ligament injuries. The control group (93 normal ankles) were age- and sex-matched with the injury group. The injured ligament carried unusual wavy collagen bundles with hyalinization (or elongation) or rupture with scar. In both groups, we found talar-side dominance of DCs, multifocus occurrence, and a high incidence of mirror-image DCs in the medial parts of the joint. However, the mirror-image lesion was multiple or large (or both) in the injury group in contrast to its restricted nature in the control. Thus, the averaged numbers of affected areas or sectors in the injury group were almost twice as large as in the controls. A significantly high incidence of DCs, especially of the mirror-image lesion, was found in the lateral malleolar facet in the injury group. Although initial DC lesions might be at a medial site in the joint, as hypothesized in the control group, the lateral ligament injury seemed to increase the dominance of DCs on the lateral site. Consequently, early evaluation and treatment for lateral ligament insufficiency is more necessary in elderly patients than in younger patients to avoid widespread development of osteoarthritis.     

Three‐dimensional imaging and analysis of human cartilage degeneration using Optical Coherence Tomography

Optical Coherence Tomography (OCT) is an evolving imaging technology allowing non‐destructive imaging of cartilage tissue at near‐histological resolution. This study investigated the diagnostic value of real time 3‐D OCT in comparison to conventional 2‐D OCT in the comprehensive grading of human cartilage degeneration. Fifty‐three human osteochondral samples were obtained from eight total knee arthroplasties. OCT imaging was performed by either obtaining a single two‐dimensional cross‐sectional image (2‐D OCT) or by collecting 100 consecutive parallel 2‐D OCT images to generate a volumetric data set of 8 × 8 mm (3‐D OCT). OCT images were assessed qualitatively according to a modified version of the DJD classification and quantitatively by algorithm‐based evaluation of surface irregularity, tissue homogeneity, and signal attenuation. Samples were graded according to the Outerbridge classification and statistically analyzed by one‐way ANOVA, Kruskal Wallis and Tukey's or Dunn's post‐hoc tests. Overall, the generation of 3‐D volumetric datasets and their multiple reconstructions such as rendering, surface topography, parametric, and cross‐sectional views proved to be of potential diagnostic value. With increasing distance to the mid‐sagittal plane and increasing degeneration, score deviations increased, too. In conclusion, 3‐D imaging of cartilage with image analysis algorithms adds considerable potential diagnostic value to conventional OCT diagnostics. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:651–659, 2015.     

大鼠尾椎间盘退变造模器械的研发与应用

目的:研制一种简便、微创、针刺深度可控的大鼠椎间盘退变模型的造模器械。方法 :自行设计一种新型针刺大鼠尾椎间盘退变的造模器械,由C型套环和针筒两部分构成。取3月龄雄性SD大鼠20只,分为针刺组(10只)和对照组(10只),将造模器械的C型套环套在鼠尾上,用21G针对针刺组的大鼠尾椎Co6/7、Co8/9椎间盘分别行横贯(10mm)和半横贯穿刺(5mm);对照组大鼠尾椎无任何处理。造模前和造模后4周时对两组大鼠的尾部行X线片和MRI检查,在X线片上测量椎间盘高度,计算目标椎间盘高度指数(DHI)比;在MRI T2像上采用Pfirrmann评分评价目标椎间盘退变情况。再处死大鼠取目标椎间盘固定切片后行番红O染色,观察椎间盘退变情况;对非针刺节段尾椎间盘内注射造影剂(碘海醇)后,X线下显影并用针抽吸髓核组织。结果:造模过程中大鼠无死亡,术后无感染等并发症。向大鼠椎间盘注射碘海醇后造影显影良好,可以抽取一定量的髓核组织。造模后4周,针刺组Co6/7和Co8/9的DHI比分别为0.65±0.07和0.73±0.09、Pfirrmann退变评分分别为4.3±0.82和3.5±0.71分,对照组分别...     

Hindlimb loading, morphology and biochemistry of articular cartilage in the ACL-deficient cat knee

The cat hindlimb is the best studied animal model of neuromuscular control, muscle mechanics/muscle morphology, and locomotor kinematics. Therefore, this model offers itself for intervention studies, where a musculoskeletal parameter is perturbed and the effects of this perturbation are compared with normal function. The objective of this study was to describe the effects of anterior cruciate ligament (ACL) transection in the cat knee and to correlate hindlimb loading with morphological and biochemical changes of articular cartilage. A distinct unloading of the deficient hindlimb was found when compared with the nonoperated hindlimb immediately after ACL transection, and persisted for about 16-18 weeks. Beyond about 18 weeks post-ACL transection, hindlimb loading returned to the symmetric pattern observed before surgery. In accordance with the expectations from the force-platform results, a decrease in muscle mass was found from muscles of the experimental hindlimb when compared to the mass of muscles from the contralateral hindlimb. This decrease of muscle mass was largest at 4 weeks and smallest at 35 weeks post-ACL transection. At 12 and 35 weeks post-ACL transection, cell density was increased and absolute amounts of hexuronic acid were elevated in the articular cartilage of the experimental knee compared with the corresponding values of the contralateral knee. Progressive changes of the articular cartilage towards osteoarthritis (OA) were not observed in the time frame of this experiment. The results suggest that anterior cruciate ligament transection in the cat produces initial changes in the knee that are similar to those observed previously in the dog and rabbit.     

Prevalence of articular cartilage degeneration in the ankle and knee joints of human organ donors

The prevalence of osteoarthritis (OA) is higher in some joints than in others. Fibrillation and full-thickness cartilage defects in the knee have been considered to be evidence of developing OA (pre-OA). While similar changes have been reported in the ankle (talocrural joint), the frequency of these changes is much higher than expected if the degeneration represents pre-OA. These observations suggest that in the ankle degenerative changes do not proceed to OA. The current study was to determine the prevalence of articular cartilage degeneration in ankles in a population of 470 bone donors with no history of joint disease. Knees from 50 donors were also available. Our data suggest that degeneration in the ankle cartilage does not appear to be a normal part of aging, was more frequent in men than women, increased with age, and occurred most often in both limbs with the same severity. In those donors with degeneration in the ankle, the knee also showed degenerative changes with an equal or higher grade. These data suggest that factors (such as altered mechanics) responsible for degeneration in one limb also cause changes in the contralateral limb and that factors affecting the ankle joints also appear to influence the knee joints. Received for publication on Dec. 2, 1998; accepted on April 22, 1999     

Modic改变与下腰椎三关节复合体退变相关性的回顾性分析

目的探讨Modic改变(modic changes,MCs)与下腰椎三关节复合体退变的相关性。方法选择2016年3月~2020年6月在本院住院治疗的231例腰椎间盘突出症(lumbar disc herniation,LDH)患者进行分析,观察MCs的发生率、椎间盘的Pfirmann分级和小关节退变分级(Weishaupt分级)的关系。结果MCs总发生率为45.31%(296/693),L_3-4、L_4-5、L₅-S₁节段MCs发生率分别为25.11%(58/231)、54.11%(125/231)和48.92%(113/231),组间差异存在统计学意义(P<0.05)。L_3-4、L_4-5和L₅-S₁节段MCsⅠ型、Ⅱ型和Ⅲ型病变节段的椎间盘退变程度均高于无MCs病变节段(P<0.05)。L_3-4节段MCsⅢ型与无MCs患者的小关节退变差异存在统计学意义(P<0.05)。L_4-5和L₅-S₁节段MCsⅡ型患者与无MCs患者的小关节退变差异存在统计学意义(P<0.05)。结论MCs与三关节复合体退变存在相关性,主要表现在MCs不同类型均与腰椎间盘退变分级相关,MCsⅡ型与腰椎小关节退行性病变相关。