Enhancement of periosteal chondrogenesis in vitro. Dose-response for transforming growth factor-beta 1 (TGF-beta 1)

Transforming growth factor-beta 1 (TGF-beta 1) has been shown to stimulate chondrogenesis in periosteal explants cultured in agarose suspension. In this study, the dose-response curve for such enhancement was measured. Periosteal explants and fascia lata were harvested from two-month-old rabbits, cultured for six weeks with 0, 0.1, 1, 5, 10, 50, or 100 ng/mL TGF-beta 1 in agarose suspension, then analyzed by histomorphometry and quantitative collagen typing. Cartilage was produced by seven of 11 (64%) of the control periosteal explants cultured in agarose suspension without TGF-beta 1. Transforming growth factor-beta 1 enhanced chondrogenesis in a dose-dependent manner in the range 0.1-100 ng/mL. It was most effective at 50 ng/mL. At very high doses (50 and 100 ng/mL) of TGF-beta 1, even fascia lata control explants exhibited chondrogenesis. These data indicate that TGF-beta 1 can induce differentiation toward cartilage production as well as enhance it once it has been initiated.