Effects of growth factors on meniscal fibrochondrocytes

To tissue engineer the knee meniscus, our laboratory follows a paradigm that includes biomaterial scaffolding, mechanical stimulation, and growth factor addition. The aim of this study was to study extracellular matrix (ECM) component uptake by meniscal fibrochondrocytes when stimulated with platelet-derived growth factor AB, transforming growth factor beta(1) (TGF-beta(1)), insulin-like growth factor type I, and basic fibroblast growth factor at various concentrations (low, medium, and high levels for each). Growth factors were applied to monolayer cultures for 3 weeks in a soluble form as part of the culture medium. Radiolabeling with [3H]proline and [(35)S]sulfate was performed to indicate collagen and glycosaminoglycan production, respectively. TGF-beta(1) is the only growth factor that increased the uptake of both components. It showed the most consistent behavior and the highest response. There is no conclusive evidence whether the high concentration of TGF-beta(1) (100 ng/mL) is better than the medium concentration (10 ng/mL). Therefore the results of this study demonstrate that TGF-beta(1) at either 10 or 100 ng/mL can be used to upregulate ECM production in monolayer cultures of meniscal fibrochondrocytes.