Tissue engineering of cartilage using poly-ɛ-caprolactone nanofiber scaffolds seeded in vivo with periosteal cells

SummaryObjectiveTo determine the potential of periosteal cells to infiltrate poly-ɛ-caprolactone (PCL) nanofiber scaffolds in vivo and subsequently produce cartilage in vitro.DesignPCL nanofiber scaffolds, with or without chitosan-coating were implanted under periosteum in 6-month-old rabbits. Transforming growth factor-β1 (TGF-β1) or vehicle was injected into each implant site. After 1, 3, 5 or 7 days, scaffolds were removed, separated from the periosteum, and the scaffolds and periosteum were cultured separately for 6 weeks under chondrogenic conditions. Sulfated glycosaminoglycan (GAG), type II collagen, DNA content, cartilage yield, and calcium deposition were then analyzed.ResultsCell infiltration was observed in all scaffolds. Cartilage formation in the uncoated scaffolds increased with duration of implantation (maximum at 7 days). Cells in the uncoated scaffolds implanted for 7 days produced significantly higher levels of both GAG [560 (95% confidence interval (CI), 107–1013) vs 228 (95% CI, 177–278) μg GAG/μg DNA] and cartilage yield [9% (95% CI, 3–14%) vs 0.02% (95% CI, 0–0.22%)] compared to chitosan-coated scaffolds (P = 0.006 or less). There was no significant difference in GAG content or cartilage yield between the TGF-β1-injected and vehicle-injected scaffolds. However, significantly more mineral deposition was detected in TGF-β1-injected scaffolds compared to vehicle-injected scaffolds (P < 0.0001). Cartilage yield from the periosteum, moreover, was significantly increased by subperiosteal TGF-β1 injections (P < 0.001). However, this response was reduced when chitosan-coated scaffolds were implanted.ConclusionsThis study demonstrates that it is possible to seed PCL nanofiber scaffolds with periosteal cells in vivo and subsequently produce engineered cartilage in vitro.