Effect of silk fibroin on degradation and in vivo biocompatibility of poly (L-lactic-co-ε-caprolactone) electronspun nanofibrous scaffolds

Objective To investigate the effect of silk fibroin(SF) on degradation and biocompatibility of poly(L-lactic acidco-e-caprolactone)(P[LLA-CL]) in vivo.Methods The scaffolds of P(LLA-CL)(w / w = 1 ∶ 1) blended with 25% of SF(SF / P[LLA-CL]) and P(LLA-CL) were prepared by electrospinning.Both kinds of scaffolds were subcutaneously implanted in 45 6-monthold rats for up to 6 months to evaluate their degradation and biocompatibility characteristics.Results Pathological sections showed P(LLA-CL) scaffold become swollen and began to separate into different layers after 3 months,and then become broken after 6 months;while SF / P(LLA-CL) scaffold largely maintained its structure after 6 months.Immunohistochemical staining showed a large number of macrophages on the surface and in P(LLA-CL) scaffolds 1 month after implantation,and they could still be found 3 months after implantation,accompanied by foreign body giant cells; while no obvious macrophages or foreign body giant cells were found in SF / P(LLA-CL) scaffolds at different time points.Examination of inflammatory gene expression showed that TNF-α and IL-10 expression in P(LLA-CL) scaffolds was significantly higher than that in SF / P(LLA-CL) scaffolds 1 week after implantation(P 0.05),the same was also true for TNF-α,IL-1β and IL-10 expression 1 month after implantation(P 0.05),for TNF-α and IL-10 expression 2 months after implantation(P 0.05),for TGF-β expression 3 months after implantation(P 0.05),and for IL-1β and TGF-β expression 6months after implantation(P 0.05).Conclusion SF incorporation can delay degradation,reduce inflammation,and improve the biocompatibility of P(LLA-CL) scaffolds,which may provide reference for scaffold design in tissue engineering.