Calcification of Intervertebral Discs in the Dachshund: A Radiographic Study of 115 Dogs at 1 and 5 Years of Age

The vertebral columns of 115 dachshunds were x-rayed at 1 and 5 years of age. This sample represented 5.7% of all dachshunds registered with the Norwegian Kennel Club in the period 1986-1988. All dogs were clinically normal at the commencement of the study. At 1 year of age calcified intervertebral discs were identified in 34 (29.6%) of the dogs and the number of calcified discs in each individual varied from 1 to 7 with a mean of 2.7. At 5 years of age calcified discs were identified in 66 (57.4%) of the dogs and the number of calcified discs in each individual varied from 1 to 11 with a mean of 3.2. Of all dogs in which calcified discs were identified at 1 year of age, 33 (97.1%) were found to have calcified discs also at 5 years of age. Of 92 calcified discs identified in the dogs at 1 year of age, 29 (31.5%) were not calcified 4 years later. Of 211 calcified discs identified in the dogs at 5 years of age, 148 (70.1%) were not calcified 4 years before. From 1 to 5 years of age, signs of spinal disease were registered in 12 (35.3%) of the dogs in which calcified discs were identified at 1 year of age, and in 7 (8.6%) of the dogs in which calcified discs were not identified at 1 year of age. Of all dogs in which one or more calcified discs had disappeared during the study-period, signs of spinal disease were registered in 9 (75.0%).     

Calcification of Intervertebral Discs in the Dachshund: An Estimation of Heritability

The heritability of calcified intervertebral discs in the dachshund was estimated using data gathered from a radiographic study. Radiographs of the vertebral columns of 274 clinically normal, 12 to 18 months old dachshunds, were examined. The dogs were offspring from 75 different sires, representing the same number of half sib groups. There were 2 to 14 offspring in each half-sib group. The number of full sib groups was 81. Calcified intervertebral discs were identified in 20.4 % of the dogs. An analysis of variance that used the data as a continuous and as an either/or-variable estimated the heritability of calcified discs to be 0.22 and 0.15 respectively. A genetic factor was found to be essential for the occurrence of calcified discs in a dog while a common environmental factor presumably resulting from non-genetic causes was significant in determining the number of discs to undergo calcification in affected dogs.     

Calcification of the Intervertebral Discs and Curvature of the Radius and Ulna: A Radiographic Survey of Finnish Miniature Dachshunds

The vertebral column of 124 randomly selected miniature dachshunds, representing 4.5% of the population registered by the Finnish Kennel Club during the years 1988 to 1996, were radiographed. The front legs were also radiographed in order to evaluate the curvature of the radius and ulna. Calcified discs were found in 75.9% of the longhaired miniature dachshunds and in 86.7% of the wirehaired ones. The occurrence of signs associated with IDD was 16.5% in longhaired and 15.6% in wirehaired miniature dachshunds. The occurrence of signs of IDD in dogs with calcified discs was 20.0% and 17.9% in long-haired and wirehaired miniature dachshunds, respectively. In dogs without calcifications only one dog showed signs of IDD. The curvature of the radius and the ulna did not differ between the dogs with signs of IDD and the healthy ones, or between the dogs with and without intervertebral calcifications. Our results indicate that radiographic eradication based on the presence of intervertebral calcifications is not suitable for breeding purposes for the Finnish miniature dachshund population because the percentage of dogs without calcifications is small.     

Modeling The Nutrientsbehavior in Intervertebral Discs: A Boundary Integral Simulation

It is a well-known fact that computational biomechanics and mechanobiology have deserved great attention by the numerical-methods community. Many efforts and works can be found in technical literature. This work deals with the modeling of nutrients and their effects on the behavior of intervertebral discs. The numerical modeling was carried out using the Boundary ELement Method (BEM) and an axisymmetric model of the disc. Concentration and production of lactate and oxygen are modeled with the BEM. Results agree well enough with those obtained using finite elements. The numerical efforts in the domain and boundary discretizations are minimized using the BEM. Also, the effect of the calcification of the disc that causes the vascularization loss has been studied. The glucose, oxygen and lactate components behavior has been analyzed applying a mixed loading-unloading process, then allowing the study of the disc-height variations due to the degradation of the disc.     

Preparation of Intact Bovine Tail Intervertebral Discs for Organ Culture

The intervertebral disc (IVD) is the joint of the spine connecting vertebra to vertebra. It functions to transmit loading of the spine and give flexibility to the spine. It composes of three compartments: the innermost nucleus pulposus (NP) encompassing by the annulus fibrosus (AF), and two cartilaginous endplates connecting the NP and AF to the vertebral body on both sides. Discogenic pain possibly caused by degenerative intervertebral disc disease (DDD) and disc herniations has been identified as a major problem in our modern society. To study possible mechanisms of IVD degeneration, in vitro organ culture systems with live disc cells are highly appealing. The in vitro culture of intact bovine coccygeal IVDs has advanced to a relevant model system, which allows the study of mechano-biological aspects in a well-controlled physiological and mechanical environment. Bovine tail IVDs can be obtained relatively easy in higher numbers and are very similar to the human lumbar IVDs with respect to cell density, cell population and dimensions. However, previous bovine caudal IVD harvesting techniques retaining cartilaginous endplates and bony endplates failed after 1-2 days of culture since the nutrition pathways were obviously blocked by clotted blood. IVDs are the biggest avascular organs, thus, the nutrients to the cells in the NP are solely dependent on diffusion via the capillary buds from the adjacent vertebral body. Presence of bone debris and clotted blood on the endplate surfaces can hinder nutrient diffusion into the center of the disc and compromise cell viability. Our group established a relatively quick protocol to "crack"-out the IVDs from the tail with a low risk for contamination. We are able to permeabilize the freshly-cut bony endplate surfaces by using a surgical jet lavage system, which removes the blood clots and cutting debris and very efficiently reopens the nutrition diffusion pathway to the center of the IVD. The presence of growth plates on both sides of the vertebral bone has to be avoided and to be removed prior to culture. In this video, we outline the crucial steps during preparation and demonstrate the key to a successful organ culture maintaining high cell viability for 14 days under free swelling culture. The culture time could be extended when appropriate mechanical environment can be maintained by using mechanical loading bioreactor. The technique demonstrated here can be extended to other animal species such as porcine, ovine and leporine caudal and lumbar IVD isolation.     

持久脊柱负荷与椎间盘组织中MMP-2表达关系的研究

目的：建立一压力可控型椎间盘退变模型,并探讨持久的脊柱负荷对椎间盘MMP-2表达的影响。方法：选用54只成年Wistar大鼠随机分为三组,分别模拟人类在站立（A组1.12N）、坐位直立（B组1.68N）、坐位前屈（C组3.08N）三种状态下椎间盘内的负荷情况,给予大鼠尾椎Co9/10椎间盘恒定压力加压,以相邻Co8/9椎间盘不加压作为对照（D组）。三组分别在3、7、14天后取受压及对照椎间盘标本,进行HE染色组织学观察及免疫组织化学分析,观察椎间盘退变情况及MMP-2在椎间盘组织中的含量变化。结果：随时间与压力的增加,椎间盘组织学评分与MMP-2表达增高（P〈0.05）,MMP-2表达与椎间盘退变程度成正相关（r=0.870,P〈0.05）。结论：持久的脊柱负荷可引起椎间盘退变及MMP-2表达增加,MMP-2可能在椎间盘退变的过程中发挥重要作用。     

持久脊柱负荷与椎间盘组织中MMP-2 表达关系的研究

目的:建立一压力可控型椎间盘退变模型,并探讨持久的脊柱负荷对椎间盘MMP-2表达的影响.方法:选用54只成年Wistar大鼠随机分为三组,分别模拟人类在站立(A组1.12N)、坐位直立(B组1.68N)、坐位前屈(C组3.08N)三种状态下椎间盘内的负荷情况,给予大鼠尾椎Co9/10椎间盘恒定压力加压,以相邻Co8/9椎间盘不加压作为对照(D组).三组分别在3、7、14天后取受压及对照椎间盘标本,进行HE染色组织学观察及免疫组织化学分析,观察椎间盘退变情况及MMP-2在椎间盘组织中的含量变化.结果:随时间与压力的增加,椎间盘组织学评分与MMP-2表达增高(P＜0.05),MMP-2表达与椎间盘退变程度成正相关(r=.870,P＜0.05).结论:持久的脊柱负荷可引起椎间盘退变及MMP-2表达增加,MMP-2可能在椎间盘退变的过程中发挥重要作用.     

Collagen II Is Essential for the Removal of the Notochord and the Formation of Intervertebral Discs

Collagen II is a fibril-forming collagen that is mainly expressed in cartilage. Collagen II–deficient mice produce structurally abnormal cartilage that lacks growth plates in long bones, and as a result these mice develop a skeleton without endochondral bone formation. Here, we report that Col2a1-null mice are unable to dismantle the notochord. This defect is associated with the inability to develop intervertebral discs (IVDs). During normal embryogenesis, the nucleus pulposus of future IVDs forms from regional expansion of the notochord, which is simultaneously dismantled in the region of the developing vertebral bodies. However, in Col2a1-null mice, the notochord is not removed in the vertebral bodies and persists as a rod-like structure until birth. It has been suggested that this regional notochordal degeneration results from changes in cell death and proliferation. Our experiments with wild-type mice showed that differential proliferation and apoptosis play no role in notochordal reorganization. An alternative hypothesis is that the cartilage matrix exerts mechanical forces that induce notochord removal. Several of our findings support this hypothesis. Immunohistological analyses, in situ hybridization, and biochemical analyses demonstrate that collagens I and III are ectopically expressed in Col2a1-null cartilage. Assembly of the abnormal collagens into a mature insoluble matrix is retarded and collagen fibrils are sparse, disorganized, and irregular. We propose that this disorganized abnormal cartilage collagen matrix is structurally weakened and is unable to constrain proteoglycan-induced osmotic swelling pressure. The accumulation of fluid leads to tissue enlargement and a reduction in the internal swelling pressure. These changes may be responsible for the abnormal notochord removal in Col2a1-null mice.Our studies also show that chondrocytes do not need a collagen II environment to express cartilage-specific matrix components and to hypertrophy. Furthermore, biochemical analysis of collagen XI in mutant cartilage showed that α1(XI) and α2 (XI) chains form unstable collagen XI molecules, demonstrating that the α3(XI) chain, which is an alternative, posttranslationally modified form of the Col2a1 gene, is essential for assembly and stability of triple helical collagen XI.     

哈萨克族成人腰稚间盘高度的放射学测量及其临床意义

目的：为人工椎间盘的设计提供形态学依据。方法：对56例哈萨克族成人腰椎（L）间盘高度进行放射学测量。结果：56例哈萨克族L1-2椎间盘高度男女性之间差异无统计学意义（P〉0．05）,L3-5椎间盘高度男、女性之间差异有统计学意L（P〈0．005-0．001）;哈萨克族与汉族腰椎间盘高度之间差异均有统计学意义（P〈0．005）。结论：哈萨克族腰椎间盘高度均大于汉族,临床上可通过对腰椎间盘间高度的测量,为人工椎间盘假体设计提供参数．     

Genetic and Functional Studies of the Intervertebral Disc: A Novel Murine Intervertebral Disc Model

Intervertebral disc (IVD) homeostasis is mediated through a combination of micro-environmental and biomechanical factors, all of which are subject to genetic influences. The aim of this study is to develop and characterize a genetically tractable, ex vivo organ culture model that can be used to further elucidate mechanisms of intervertebral disc disease. Specifically, we demonstrate that IVD disc explants (1) maintain their native phenotype in prolonged culture, (2) are responsive to exogenous stimuli, and (3) that relevant homeostatic regulatory mechanisms can be modulated through ex-vivo genetic recombination. We present a novel technique for isolation of murine IVD explants with demonstration of explant viability (CMFDA/propidium iodide staining), disc anatomy (H&E), maintenance of extracellular matrix (ECM) (Alcian Blue staining), and native expression profile (qRT-PCR) as well as ex vivo genetic recombination (mT/mG reporter mice; AdCre) following 14 days of culture in DMEM media containing 10% fetal bovine serum, 1% L-glutamine, and 1% penicillin/streptomycin. IVD explants maintained their micro-anatomic integrity, ECM proteoglycan content, viability, and gene expression profile consistent with a homeostatic drive in culture. Treatment of genetically engineered explants with cre-expressing adenovirus efficaciously induced ex vivo genetic recombination in a variety of genetically engineered mouse models. Exogenous administration of IL-1ß and TGF-ß3 resulted in predicted catabolic and anabolic responses, respectively. Genetic recombination of TGFBR1^fl/fl explants resulted in constitutively active TGF-ß signaling that matched that of exogenously administered TGF-ß3. Our results illustrate the utility of the murine intervertebral disc explant to investigate mechanisms of intervertebral disc degeneration.