Development of Nanofiber Sponges-Containing Nerve Guidance Conduit for Peripheral Nerve Regeneration in Vivo

In the study of hollow nerve guidance conduit (NGC), the dispersion of regenerated axons always confused researchers. To address this problem, filler-containing NGC was prepared, which showed better effect in the application of nerve tissue engineering. In this study, nanofiber sponges with abundant macropores, high porosity, and superior compressive strength were fabricated by electrospinning and freeze-drying. Poly(l-lactic acid-co-ε-caprolactone)/silk fibroin (PLCL/SF) nanofiber sponges were used as filler to prepare three-dimensional nanofiber sponges-containing (NS-containing) NGC. In order to study the effect of fillers for nerve regeneration, hollow NGC was set as control. In vitro cell viability studies indicated that the NS-containing NGC could enhance the proliferation of Schwann cells (SCs) due to the macroporous structure. The results of hematoxylin-eosin (HE) and immunofluorescence staining confirmed that SCs infiltrated into the nanofiber sponges. Subsequently, the NS-containing NGC was implanted in a rat sciatic nerve defect model to evaluate the effect in vivo. NS-containing NGC group performed better in nerve function recovery than hollow NGC group. In consideration of the walking track and triceps weight analysis, NS-containing NGC was close to the autograft group. In addition, histological and morphological analyses with HE and toluidine blue (TB) staining, and transmission electron microscope (TEM) were conducted. Better nerve regeneration was observed on NS-containing NGC group both quantitatively and qualitatively. Furthermore, the results of three indexes' immuno-histochemistry and two indexes' immunofluorescence all indicated good nerve regeneration of NS-containing NGC as well, compared with hollow NGC. The results demonstrated NS-containing NGC had great potential in the application of peripheral nerve repair.