Enhanced proliferation and chondrogenic differentiation of human synovium-derived stem cells expanded with basic fibroblast growth factor.

Synovium-derived stem cell (SDSC) is one of valuable sources for cartilage regeneration. Basic fibroblast growth factor (bFGF) was reported to augment the differentiation potential of mesenchymal stem cells originating from a variety of sources. In this study, we applied various concentrations of bFGF to monolayer cultures of SDSCs and evaluated its effects on proliferation and chondrogenesis. SDSCs expressed mRNAs of FGF receptor 1, 2, 3, and 4, but produced only FGF receptor 3 protein. The SDSCs were expanded as monolayer supplemented with various concentrations of bFGF (0, 0.1, 1, 10, and 100 ng/mL) before chondrogenesis. Cell shrinkage and increased actin expression was noted as well as enhanced proliferation by bFGF treatment in monolayer cultures. Cell surface marker CD34 and CD49a expression of SDSCs was decreased with 10 and 100 ng/mL of bFGF. In micromass pellet cultures, bFGF-treated SDSCs showed augmented sizes, weights, and glycosaminoglycan accumulation of pellets by bFGF supplementation. Messenger RNA and protein expression of type II and type X collagen were upregulated in pellets cultured bFGF. These results demonstrated that bFGF was an effective agent for the enhancement of SDSC proliferation and chondrogenesis. From the results in this study, we could elect the 10 ng/mL of bFGF as an optimal concentration for pretreatment of SDSCs before chondrogenic differentiation.