Dentin sialophosphoprotein (DSPP), which expresses and synthesizes in odontoblasts of dental pulp, is a critical protein for normal teeth mineralization. Originally, DSPP was identified as a dentin-specific protein. In 2010, DSPP was also found in femoral head cartilage, and it is still unclear what roles DSPP play in femoral head cartilage formation, growth, and maintenance. To reveal biological functions of DSPP in the femoral head cartilage, we examined Dspp null mice compared with wild-type (WT) mice to observe DSPP expression as well as localization in WT mice and to uncover differences of femoral head cartilage, bone morphology, and structure between these two kinds of mice. Expression data demonstrated that DSPP had heterogeneous fragments, expressed in each layer of femoral head cartilage and subchondral bone of WT mice. Dspp null mice exhibited a significant reduction in the thickness of femoral head cartilage, with decreases in the amount of proliferating cartilage cells and increases in apoptotic cells. In addition, the subchondral bone mineralization decreased, and the expressions of vessel markers (vascular endothelial growth factor [VEGF] and CD31), osteoblast markers (Osterix and dentin matrix protein 1 [DMP1]), osteocyte marker (sclerostin [SOST]), and osteoclast marker (tartrate-resistant acid phosphatase [TRAP]) were remarkably altered. These indicate that DSPP deletion can affect the proliferation of cartilage cells in the femoral head cartilage and endochondral ossification in subchondral bone. Our data clearly demonstrate that DSPP plays essential roles in the femoral head cartilage growth and maintenance and subchondral biomineralization.

牙本质唾液酸磷蛋白 (DSPP) 在牙髓的成牙本质细胞中表达和合成，是正常牙齿矿化的关键蛋白质。最初，DSPP 被鉴定为牙本质特异性蛋白质。2010年，在股骨头软骨中也发现了DSPP，目前尚不清楚DSPP在股骨头软骨的形成、生长和维持中起什么作用。为了揭示 DSPP 在股骨头软骨中的生物学功能，我们检查了Dspp将 null 小鼠与野生型 (WT) 小鼠进行比较，以观察 WT 小鼠中的 DSPP 表达和定位，并揭示这两种小鼠之间股骨头软骨、骨形态和结构的差异。表达数据表明，DSPP 具有异质片段，在 WT 小鼠的股骨头软骨和软骨下骨的每一层中表达。数字信号处理器null 小鼠的股骨头软骨厚度显着减少，增殖软骨细胞数量减少，凋亡细胞增加。此外，软骨下骨矿化减少，血管标志物（血管内皮生长因子[VEGF]和CD31）、成骨细胞标志物（Osterix和牙本质基质蛋白1[DMP1]）、骨细胞标志物（硬化蛋白[SOST]）、和破骨细胞标记物（抗酒石酸酸性磷酸酶 [TRAP]）显着改变。这些表明DSPP缺失可以影响股骨头软骨中软骨细胞的增殖和软骨下骨中的软骨内骨化。我们的数据清楚地表明，DSPP 在股骨头软骨生长和维持以及软骨下生物矿化中起着至关重要的作用。