Bio-compatibility of type I/III collagen matrix for peripheral nerve reconstruction

Nerve gaps are usually bridged by autografts. With improving technical methods biocompatible conduits may become an alternative graft to reconstruct nerves. Non-neural conduits fail to support regeneration over larger gaps due to lacking viable Schwann cells. Thus, tissue engineering of nerves is focusing on implantation of viable Schwann cells into suitable scaffolds. In this study, we tested collagen type I/III tubes as a potential nerve guiding matrix. Revascularization, foreign body reaction, biodegradation and Schwann cell settlement were evaluated by immunocytochemistry, light, fluorescence and scanning electron microscopy, after different implantation times. The conduits were completely revascularized between day 5 and 7 post-operatively and well integrated into the host tissue. Host response was characterized by a moderate invasion of ED1/ED2-positive macrophages. Biodegradation of the tubes was slowly enough to maintain a stable support structure for extended regeneration processes. Implanted Schwann cells adhered, survived and proliferated on the inner surface of the conduits and were able to form nerve guiding columns of Büngner. From this results, we conclude that collagen-type I/III can serve as template to design "living" nerve conduits, which may be able to ensure nerve regeneration through extended nerve gaps.