Weft-knitted silk-poly(lactide-co-glycolide) mesh scaffold combined with collagen matrix and seeded with mesenchymal stem cells for rabbit Achilles tendon repair

Natural silk fibroin fiber scaffolds have excellent mechanical properties, but degrade slowly. In this study, we used poly(lactide-co-glycolide) (PLGA, 10:90) fibers to adjust the overall degradation rate of the scaffolds and filled them with collagen to reserve space for cell growth. Silk fibroin-PLGA (36:64) mesh scaffolds were prepared using weft-knitting, filled with type I collagen, and incubated with rabbit autologous bone marrow-derived mesenchymal stem cells (MSCs). These scaffold–cells composites were implanted into rabbit Achilles tendon defects. At 16 weeks after implantation, morphological and histological observations showed formation of tendon-like tissues that expressed type I collagen mRNA and a uniformly dense distribution of collagen fibers. The maximum load of the regenerated Achilles tendon was 58.32% of normal Achilles tendon, which was significantly higher than control group without MSCs. These findings suggest that it is feasible to construct tissue engineered tendon using weft-knitted silk fibroin-PLGA fiber mesh/collagen matrix seeded with MSCs for rabbit Achilles tendon defect repair.