Histochemical evidences on the chronological alterations of the hypertrophic zone of mandibular condylar cartilage
Histochemical evidences on the chronological alterations of the hypertrophic zone of mandibular condylar cartilage
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DOI：
10.1002/jemt.20211
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发表时间：
2005-08-15
影响因子：
2.5
通讯作者：
Maeda, T
中科院分区：
文献类型：
--
作者：
Hossain, KS;Amizuka, N;Maeda, T
肥大的软骨细胞缺乏增殖能力，因此允许基质矿化以及下颌髁突和骺软骨中的骨血管侵入。本研究旨在验证小鼠下颌骨髁突发育过程中肥大软骨细胞的组织学形态是否处于稳定状态。X型胶原免疫组化明显区分了纤维层，如前所述的“关节区”，“关节层”，“休息区”从肥大区。有趣的是，X型胶原阳性肥大区在整个髁突的比例似乎在早期较高，但在后期下降。肥大区的一些明显致密的细胞显示增殖细胞核抗原（PCNA）免疫反应，表明细胞增殖的早期阶段的潜力。相反，随着小鼠的成熟，它们进一步增大并呈现肥大软骨细胞的典型特征。在早期肥大区也可观察到凋亡细胞，但在晚期则没有。与肥大软骨细胞的形态学结构一致，碱性磷酸酶、骨桥蛋白和I型胶原的免疫反应在后期突出，但在早期不突出。软骨基质在早期表现出分散的矿化斑块，但在后期其体积和连通性增加。因此，这些免疫反应以及凋亡的时空发生可能反映了肥大细胞在早期阶段的早熟，并暗示在下颌骨髁状突的早期发育过程中的生理相关性。
The hypertrophic chondrocytes lack the ability to proliferate, thus permitting matrix mineralization as well as vascular invasion from the bone in both the mandibular condyle and the epiphyseal cartilage. This study attempted to verify whether the histological appearance of the hypertrophic chondrocytes is in a steady state during postnatal development of the mouse mandibular condyle. Type X collagen immunohistochemistry apparently distinguished the fibrous layer described previously as the "articular zone," "articular layer," and "resting zone" from the hypertrophic zone. Interestingly, the ratio of the type X collagen-positive hypertrophic zone in the entire condyle seemed higher in the early stages but decreased in the later stages. Some apparently compacted cells in the hypertrophic zone showed proliferating cell nuclear antigen (PCNA) immunoreaction, indicating the potential for cell proliferation at the early stages. As the mice matured, in contrast, they further enlarged and assumed typical features of hypertrophic chondrocytes. Apoptotic cells were also discernible in the hypertrophic zone at the early but not later stages. Consistent with morphological configurations of hypertrophic chondrocytes, immunoreactions for alkaline phosphatase, osteopontin, and type I collagen were prominent at the later stage, but not the early stage. Cartilaginous matrices demonstrated scattered patches of mineralization at the early stage, but increased in their volume and connectivity at the later stage. Thus, the spatial and temporal occurrence of these immunoreactions as well as apoptosis likely reflect the prematurity of hypertrophying cells at the early stage, and imply a physiological relevance during the early development of the mandibular condyles.