Adipocyte-derived and dedifferentiated fat cells promoting facial nerve regeneration in a rat model

Background: Dedifferentiated fat cells, obtained from the ex vivo ceiling culture of mature adipocytes of mammals, have a high proliferative potential and pluripotency. The authors transplanted dedifferentiated fat cells into a nerve defect created in rat facial nerve and evaluated nerve regeneration ability. Methods: The buccal branch of the facial nerve of rats was exposed, and a 7-mm nerve defect was created. Green fluorescent protein-positive dedifferentiated fat cells prepared from adipocytes were mixed with type 1 collagen scaffold and infused into a silicone tube, which was then transplanted into the nerve defect in a green fluorescent protein-negative rat (the dedifferentiated fat group). Regenerated nerves were excised at 13 weeks after transplantation and examined histologically and physiologically. The findings were compared with those of autografts and silicone tubes loaded with collagen gel alone (the control group) transplanted similarly. Results: Axon diameter of regenerated nerve increased significantly in the dedifferentiated fat group compared with the control group, whereas no significant difference was found between the dedifferentiated fat and autograft groups. Myelin thickness was found to be largest in the autograft group, followed by the dedifferentiated fat and the control groups, showing significant differences between all pairs of groups. Evaluation of physiologic function of nerves by compound muscle action potential revealed a significantly better result in the dedifferentiated fat group than in the control group. The regenerated nerves in the dedifferentiated fat group had S100 and green fluorescent protein-double-positive Schwann-like supportive cells. Conclusion: After being transplanted into a facial nerve defect, dedifferentiated fat cells promoted the maturation of the regenerated nerve.