Cartilage comprises chondrocytes and extracellular matrix. The matrix contains different collagens, proteoglycans, and growth factors produced by chondroprogenitor cells that differentiate from proliferating to hypertrophic chondrocytes. In vitro chondrocyte growth is challenging due to differences in behaviour between 2D and 3D cultures. Our aim is to establish a murine 3D spheroid culture method using chondrocytes to study the complex interaction of cells on the chondro-osseous border during enchondral ossification. Primary chondrocytes were isolated from the knee of WT new-born mice and used to form 10,000 cell number spheroids. We used the ATDC5-chondrocyte cell line as an alternative cell type. Spheroids were observed for 7, 14, and 21 days before embedding in paraffin for slicing. Alcian blue staining was performed to identify proteoglycan positive areas to prove the formation of extracellular matrix in spheroids. Collagen type 2, and Collagen type X expression were analyzed via quantitative real-time PCR and immunohistochemistry.Introduction
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