A Novel Scaffold with Longitudinally Oriented Microchannels Promotes Peripheral Nerve Regeneration

Longitudinally oriented microstructures are essential for a nerve scaffold to promote significant regeneration of injured peripheral axons across nerve gaps. Extensive attention has been devoted to develop scaffolds with inner structures mimicking the nerve-guiding basal lamina microchannels in autografts. However, to date, little information has been obtained about scaffolds with similar inner microstructures, and the efficacy of such scaffolds in bridging peripheral nerve gaps in vivo has never been examined. In the present study, we describe a novel nerve-guiding collagen-chitosan (CCH) scaffold with inner dimensions resembling the basal lamina microchannels of normal nerves. The scaffold has a number of structural advantages, including longitudinally orientated microchannels and extensive interconnected pores between the parallel microchannels. We evaluated the efficacy of the CCH scaffold to bridge a 15-mm-long sciatic nerve defect in rats using a combination of morphological and functional techniques. The in vivo animal study showed that the CCH scaffold achieved nerve regeneration and functional recovery equivalent to that of an autograft, without the exogenous delivery of regenerative agents or cell transplantation. These findings demonstrate that CCH scaffolds may be used as alternatives to nerve autografts for peripheral nerve regeneration.