A scaffold-free Bio 3D nerve conduit for repair of a 10-mm peripheral nerve defect in the rats

IntroductionA Bio 3D printed nerve conduit was reported to promote nerve regeneration in a 5mm nerve gap model. The purpose of this study was to fabricate Bio 3D nerve conduits suitable for a 10mm nerve gap and to evaluate their capacity for nerve regeneration in a rat sciatic nerve defect model. Materials and MethodsEighteen F344 rats with immune deficiency (9-10weeks old; weight, 200-250g) were divided into three groups: a Bio 3D nerve conduit group (Bio 3D, n = 6), a nerve graft group (NG, n = 6), and a silicon tube group (ST, n = 6). A 12-mm Bio 3D nerve conduit or silicon tube was transplanted into the 10-mm defect of the right sciatic nerve. In the nerve graft group, reverse autografting was performed with an excised 10-mm nerve segment. Assessments were performed at 8weeks after the surgery. ResultsIn the region distal to the suture site, the number of myelinated axons in the Bio 3D group were significantly larger compared with the silicon group (2,548 vs. 950, p<.05). The myelinated axon diameter (MAD) and the myelin thickness (MT) of the regenerated axons in the Bio 3D group were significantly larger compared with those of the ST group (MAD: 3.09 vs. 2.36 mu m; p<.01; MT: 0.59 vs. 0.40 mu m, p<.01). ConclusionsThis study indicates that a Bio 3D nerve conduit can enhance peripheral nerve regeneration even in a 10mm nerve defect model.