Comparative Morphological and Biochemical Analysis of Hypertrophic, Non-Hypertrophic and L, 25(Oh)2d3 Treated Non-Hypertrophic Chondrocytes

A comparative study of Type X collagen expression, chondrocyte morphology, and the expression of two genes controlling chondrocyte morphology (β-actin and fibronectin) was carried out on chondrocytes derived from a tissue that remains as permanent hyaline cartilage in vivo (embryonic chicken caudal sterna), from a tissue that undergoes endochondral replacement (embryonic chicken ventral vertebrae) and caudal sternal chondrocytes treated with 1, 25(OH)2D3. Under identical in vitro growth conditions and times, sternal chondrocytes grew as rounded non-adherent cells, and vertebral chondrocytes grew as adherent polygonal cells. Upon treatment with 10−8 M l, 25(OH)2D3 over a twelve day period the sternal chondrocytes showed complete adherence and took on an identical appearance as the vertebral chondrocytes. Cellular adherence of both vertebral and 1, 25(OH)2D3 treated sternal chondrocytes was associated with 10 × increased β-actin, fibronectin and their corresponding mRNA's. Changes in connective tissue expre...