Vornehm S I, Dudhia J, Von der Mark K, Aigner T
Institute of Experimental Medicine and Connective Tissue Research, University of Erlangen-Nürnberg, Germany.
Matrix Biol. 1996 Jul;15(2):91-8. doi: 10.1016/s0945-053x(96)90150-x.
Coordinate differentiation of the chondrocytes plays a crucial role during skeletal development. In the cascade of endochondral bone formation, mature chondrocytes of the fetal growth plate represent metabolically highly active cells. They show high expression levels of the major cartilage matrix genes, collagen types II, IX, and XI, the major cartilage proteoglycan aggrecan, and proteoglycan link protein. The strongest signals are found in areas of maximal growth, the proliferative and upper hypertrophic zones. The major cartilage matrix components are co-expressed by the chondrocytes of the resting and proliferative zones. Type X collagen is restricted to lower hypertrophic chondrocytes. Interestingly, in the lower hypertrophic zone type IX collagen, but not type II and XI collagen, mRNA expression is downregulated, indicating a discoordinate expression of these collagen types in hypertrophic chondrocytes. The results of this study confirm the strict zonal differentiation pattern of chondrocytes in the developing fetal growth plate, which can be monitored by the expression patterns of its major expression products, the collagen subtypes and aggrecan and proteoglycan link protein.
软骨细胞的协调分化在骨骼发育过程中起着至关重要的作用。在软骨内成骨的级联反应中，胎儿生长板中的成熟软骨细胞是代谢高度活跃的细胞。它们显示出主要软骨基质基因、II型、IX型和XI型胶原蛋白、主要软骨蛋白聚糖聚集蛋白聚糖以及蛋白聚糖连接蛋白的高表达水平。最强的信号出现在最大生长区域，即增殖区和上肥大区。静止区和增殖区的软骨细胞共同表达主要的软骨基质成分。X型胶原蛋白仅限于下肥大软骨细胞。有趣的是，在较低的肥大区，IX型胶原蛋白的mRNA表达下调，而II型和XI型胶原蛋白则没有，这表明这些胶原蛋白类型在肥大软骨细胞中表达失调。这项研究的结果证实了发育中的胎儿生长板中软骨细胞严格的区域分化模式，这可以通过其主要表达产物、胶原蛋白亚型、聚集蛋白聚糖和蛋白聚糖连接蛋白的表达模式来监测。
