a cellular approach to cartilage repair and regeneration; regulation of articular chondrocyte markers by tgf-β at high density cell culture

This research aimed to investigate the role of different isomers of transforming growth factor-β (tgf-β) in the up/downregulation of chondrocyte markers. the monolayer culture of the chondrocyte resulted in the dedifferentiation of cells and the production of stress fibers, which was prevented by high-density and 3d chondrocyte culture. this work demonstrated a successful and typical cell engineering of chondrocyte monolayers with our model using isolated primary rat articular chondrocytes (rac) through cell seeding, 2d cell expansion, and differentiation in vitro, without the use of a bioreactor. therefore, the same model can be used for the isolation of human articular chondrocytes (hac) from clinically approved human biopsies for autologous chondrocyte implantation and/or monolayer production (e.g., cytotoxicity tests). our model can also be used for the direct expansion of the limited number of chondrocytes obtained from rac or hac, reaching higher densities similar to those used in conventional cartilage tissue engineering based on cells expanded by 2d cultures. our results indicated that the combination of transforming growth factorbeta (tgf-β), including tgf-β1, 2, and 3, increased the production of collagen type-ii. additionally, manipulated tgf-β1, 2, and 3 negatively regulated cell proliferation. the amount of chondroitin sulfate proteoglycan (cspg) and laminin were reduced by all three isomers of tgf-β and their manipulated forms, but the expression of fibronectin and s-100 proteins was not significantly affected by tgf-β isomers. our results suggest that tgf-β1 and 2 could be utilized in the fabrication of biodegradable scaffolds for 3d chondrocyte culture due to their ability to induce cell proliferation.