Two-component collagen nerve guides support axonal regeneration in the rat peripheral nerve injury model.

Progress in material development has enabled the production of nerve guides that increasingly resemble the characteristics of an autologous nerve graft. In the present study, 20 mm adult rat sciatic nerve defects were bridged with the collagen-based, two-component nerve guide 'Neuromaix', the commercially available NeuraGen® nerve tube or an autologous nerve graft. Neuromaix was able to support structural as well as functional regeneration across this gap. The majority of the axons grew across the scaffold into the distal nerve segment and retrograde tracing confirmed that these axons were of somatosensory and motor origin. Histomorphology revealed that axons regenerating through Neuromaix exhibited reduced myelin sheath thickness, whereas axon diameter and axon density were comparable to those of the autograft. Neuromaix implantation resulted in reinnervation of the gastrocnemius muscle to a level that was not significantly different from that supported by the autograft, as demonstrated by electrophysiology. Our findings show that the use of the Neuromaix scaffold not only allowed axonal regeneration across large nerve gaps, but that the regenerating axons were also able to functionally reinnervate the muscles. These data provide a promising perspective for the first in human application of the materials.