Analysis of gene expression pattern and extracellular environment of connective tissue growth factor (CCN2/CTGF) during secondary ossification center formation

CCN2/结缔组织生长因子(CCN2)是间充质组织发育的重要信号调节因子。本研究探讨了CCN2作为一种支持血管生成和软骨生成的因子在小鼠胫骨平台次级骨化中心发育过程中的定位和表达。免疫组织化学染色显示CCN2广泛分布于软骨细胞肥大、软骨管进入肥大团块的骨痂中央区的表达细胞周围。此外，在次级骨化中心发现金属蛋白酶9(MMP9)、硫酸乙酰肝素蛋白多糖(Perlecan)和CCN2的重叠分布。这些发现表明，CCN2参与了骨骺血管化和重塑的建立，这最终决定了发育中的骨痂软骨的次级骨化中心。

CCN2/connective tissue growth factor (CCN2) is a critical signaling modulator of mesenchymal tissue development. This study investigated the localization and expression of CCN2 as a factor supporting angiogenesis and chondrogenesis during development of secondary ossification centers in the mouse tibial epiphysis. Immunostaining showed that CCN2 was distributed broadly around the expressed cells located in the central region of the epiphysis, where the chondrocytes become hypertrophic and the cartilage canal enters into the hypertrophic mass. Furthermore, an overlapping distribution of metalloproteinase (MMP)9 and Heparan sulfate proteoglycan(Perlecan) and CCN2 was found in the secondary ossification center. These findings suggest that the CCN2 is involved in establishing epiphyseal vascularization and remodeling, which eventually determines the secondary ossification center in the developing epiphysial cartilage