Effect of transforming growth factor-beta 1 (TGF-ß1) released from a scaffold on chondrogenesis in an osteochondral defect model in the rabbit
AbstractArticular cartilage repair might be stimulated by the controlled delivery of therapeutic factors. We tested the hypotheses whether TGF-ß1 can be released from a polymeric scaffold over a prolonged period of time in vitro and whether its transplantation modulates cartilage repair in vivo. Unloaded control or TGF-ß1 poly(ether-ester) copolymeric scaffolds were applied to osteochondral defects in the knee joints of rabbits. In vitro, a cumulative dose of 9 ng TGF-ß1 was released over 4 weeks. In vivo, there were no adverse effects on the synovial membrane. Defects treated with TGF-ß1 scaffolds showed no significant difference in individual parameters of chondrogenesis and in the average cartilage repair score after 3 weeks. There was a trend towards a smaller area (42.5 %) of the repair tissue that stained positive for safranin O in defects receiving TGF-ß1 scaffolds. The data indicate that TGF-ß1 is released from emulsion-coated scaffolds over a prolonged period of time in vitro and that application of these scaffolds does not significantly modulate cartilage repair after 3 weeks in vivo. Future studies need to address the importance of TGF-ß1 dose and release rate to modulate chondrogenesis.