Ganey T M, Ogden J A, Sasse J, Neame P J, Hilbelink D R
Shriners Hospital for Crippled Children, Tampa Unit, USA.
Anat Rec. 1995 Mar;241(3):425-37. doi: 10.1002/ar.1092410318.
Cartilage canals are perichondral invaginations of blood vessels and connective tissue that are found within the epiphyses of most mammalian long bones. Functionally, they provide a means of transport of nutrients to the hyaline cartilage, a mechanism for removal of metabolic wastes, and a conduit for stem cells that are capable of initiating and sustaining ossification of the chondroepiphysis. Morphological and biomolecular changes of the chondroepiphyses appear to potentiate ossification within the chondroepiphyses of developing bones.
As both cell migration and vascular invasion are anchorage dependent processes, antibodies to laminin and Type IV collagen were used to assess compositional changes in the basement membrane of cartilage canals accompanying epiphyseal ossification.
Differences in chronological appearance, as well as, in distribution between the two components were noted in the chondroepiphysis. Laminin was distributed throughout the connective tissue of cartilage canal at all stages of development, and not limited to an association with the vascular lumen. Type IV collagen was not present during the initial perichondral invagination. Although staining for Type IV collagen was later acquired, its distribution was restricted to a discontinuous rimming of the periphery of the canal, and a diffuse presence within the intra-canalicular mesenchyme.
Concurrent with chondrocyte hypertrophy and mineralization of the hyaline matrix, rapid changes in both the morphology of the vessel and distribution of the antibodies were detected. In addition to the presence of laminin at the interface of the endothelium and the hyaline matrix, a wide distribution within the connective tissue components of the newly ossifying matrix of epiphyseal bone could be detected. Type IV collagen remained closely associated with the lumens of the intra-canalicular vessels throughout the transition. Following ossification of the secondary center, staining for Type IV collagen could then be detected in the bone-forming regions of transforming matrix as well, clearly delineating the individual vessels within the newly formed marrow spaces. This suggests that bone formation is intimately related to vessel staining for collagen type IV, and that acquired vessel competence is a facet of endochondral bone formation that results from provisional matrix changes. Furthermore, the data suggests that during bone formation under tension, basement membrane deposition can be demonstrated without an intermediary hyaline matrix hypertrophic chondrocyte phase. This data was interpreted to suggest that chondrocyte hypertrophy at the growth plate may be a reaction to vascular invasion, that in turn, stimulates adjacent chondrocyte proliferation.
软骨管是血管和结缔组织的软骨膜内陷，存在于大多数哺乳动物长骨的骨骺中。在功能上，它们为透明软骨提供营养物质运输的途径、代谢废物清除的机制，以及干细胞的通道，这些干细胞能够启动和维持软骨骨骺的骨化。软骨骨骺的形态学和生物分子变化似乎会增强发育中骨骼软骨骨骺内的骨化。
由于细胞迁移和血管侵入都是锚定依赖性过程，因此使用层粘连蛋白和IV型胶原抗体来评估伴随骨骺骨化的软骨管基底膜的成分变化。
在软骨骨骺中观察到这两种成分在出现时间和分布上的差异。层粘连蛋白在发育的各个阶段都分布于软骨管的结缔组织中，并不局限于与血管腔相关联。在最初的软骨膜内陷阶段不存在IV型胶原。尽管后来获得了IV型胶原的染色，但它的分布仅限于软骨管周边的不连续边缘，以及管内间充质中的弥漫性存在。
与软骨细胞肥大和透明基质矿化同时发生的是，检测到血管形态和抗体分布的快速变化。除了在内皮细胞和透明基质的界面存在层粘连蛋白外，还能在骨骺骨新骨化基质的结缔组织成分中检测到其广泛分布。在整个转变过程中，IV型胶原始终与管内血管腔紧密相关。在次级骨化中心骨化后，在转化基质的成骨区域也能检测到IV型胶原的染色，清晰地勾勒出新形成的骨髓腔内的各个血管。这表明骨形成与IV型胶原的血管染色密切相关，并且获得的血管能力是软骨内骨形成的一个方面，是由临时基质变化导致的。此外，数据表明在张力下的骨形成过程中，无需中间的透明基质肥大软骨细胞阶段即可证明基底膜沉积。这些数据被解释为表明生长板处的软骨细胞肥大可能是对血管侵入的反应，而血管侵入反过来又刺激相邻软骨细胞增殖。
