Facial Nerve Regeneration in Immunodeficient Rats Using a Bio 3D Conduit Fabricated From Human Dental Pulp Stem Cells

Tumor surgery or trauma in the maxillofacial region may cause injuries to peripheral nerves, such as facial nerves. The gold standard of treatment for peripheral nerve injury has been autologous nerve grafting. Since new peripheral nerve regeneration technologies are required, three-dimensional (3D) structures fabricated only from cells by using Bio 3D printers are attracting attention. Dental pulp stem cells (DPSCs) are a promising option as a cell source because of their high clonogenic, proliferative, and multidifferentiation potentials. In this study, nerve conduits were fabricated from DPSCs using a Bio 3D printer, and their potential for nerve regeneration was evaluated in a rat facial nerve injury model. DPSCs were obtained from wisdomteeth of patients and cultured. A 5 mm Bio 3D conduit was fabricated by using a Bio 3D printer. Six F344 rnu-/rnu- rats with immune deficiency (10 weeks old, body weight: 190-240 g) were divided into two groups: a Bio 3D group (n = 3) and a silicone tube group (n = 3). The 5 mm Bio 3D conduits and silicone tubes were transplanted into 4 mm defects. Evaluation was performed at 12 weeks after the surgery. The whiskers of immunodeficient rats in both groups were moving. The number of myelinated axons was larger in the Bio 3D group than in the silicone group. Myelinated axon diameter (MAD) and myelin thickness (MT) of regenerated axons in the Bio 3D group were significantly greater than those in the silicone group (MAD: p  < 0.01, MT: p  < 0.05). In this study, we confirmed the nerve regeneration potential of Bio 3D structures fabricated from DPSCs that were transplanted into a rat model of facial nerve injury.