Abstract
Synovial membrane has been shown to contain mesenchymal stem cells. We hypothesized that an enriched population of synovial fibroblasts would undergo chondrogenic differentiation and secrete cartilage extracellular matrix to a greater extent than would a mixed synovial cell population (MSCP). The optimum doses of transforming growth factor beta 1 (TGF-beta1) and insulin-like growth factor 1 (IGF-1) for chondrogenesis were investigated. CD14-negative isolation was used to obtain a porcine cell population enriched in type-B synovial fibroblasts (SFB) from an MSCP. The positive cell surface markers in SFB were CD90, CD44, and cadherin-11. SFB and MSCP were cultured in the presence of 20 ng/mL TGF-beta1 for 7 days, and SFB were demonstrated to have higher chondrogenic potential. Further dose-response studies were carried out using the SFB cells and several doses of TGF-beta1 (2, 10, 20, and 40 ng/mL) and/or IGF-1 (1, 10, 100, and 500 ng/mL) for 14 days. TGF-beta1 supplementation was essential for chondrogenesis and prevention of cell death, whereas IGF-1 did not have a significant effect on the SFB cell number or glycosaminoglycan production. This study demonstrates that the CD14-negative isolation yields an enhanced cell population SFB that is more potent than MSCP as a cell source for cartilage tissue engineering.