Fujisawa T et al. - CCN family 2/connective tissue growth factor (CCN2/CTGF) may be a suitable agent for promoting differentiation and growth of auricular chondrocytes, while preventing mineralization and apoptosis, suggesting that it might be useful for the repair or reconstruction of elastic cartilage. Methods
A study to document that CCN2/CTGF promotes growth and differentiation of auricular chondrocytes
Isolated auricular chondrocytes were treated with human recombinant CCN2/CTGF or infected with adenovirus harboring the ccn2/ctgf gene
Cell proliferation was measured by [3H] thymidine incorporation and MTS assay
Changes in gene expression of auricular chondrocyte markers were monitored by RT-PCR, Northern hybridization, and histological analysis
For in vivo studies, auricular chondrocytes were cultured and implanted sc
Ectopically formed cartilage was subjected to histological analysis
Cell death was monitored by in situ TUNEL analysis
Results
CCN2/CTGF stimulated proliferation, differentiation and synthesis of elastin and proteoglycans in a dose-dependent manner
CCN2/CTGF caused a 2.5-fold increase in the expression of elastin resulting in enhanced deposition of elastin fibers
Mineralization was not induced
In contrast, CCN2/CTGF stimulated expression of matrix gla protein which is known to impair mineralization
Pretreatment of auricular chondrocytes with CCN2/CTGF and sc implantation enhanced the growth of ectopic auricular cartilage pieces expressing II and X collagen
Notably, chondrocyte apoptosis was impaired by CCN2/CTGF
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