PLGA artificial nerve conduits with dental pulp cells promote facial nerve regeneration.

A number of recent studies have shown the effectiveness of tubulation, using neural progenitor cells or Schwann cells, for promoting nerve regeneration. However, the use of neural cells from other neural donor tissues has potentially serious clinical complications. Therefore, we focused on dental pulp as a new cell source for use in such artificial conditions. Previously, we showed that silicone tubes filled with dental pulp cells (DPCs) promoted facial nerve regeneration in rats. However, the use of silicone tubes requires a secondary removal operation because they may give rise to chronic inflammation and pain. Therefore, to avoid this procedure, a new artificial device was prepared from a degradable poly-DL-lactide-co-glycolide (PLGA) tube containing DPCs, and its effectiveness for repairing gaps in the facial nerves of rats was investigated. A PLGA tube containing rat DPCs embedded in a collagen gel was transplanted into a gap in a rat facial nerve. Five days after transplantation, the facial nerves connected by the PLGA tubes containing DPCs were repaired more quickly than the control nerves. The PLGA tubes were resorbed in vivo and nerve regeneration was observed 2 months after the transplantation. Immunostaining showed that Tuj1-positive axons were present in the regenerated nerves 2 months after transplantation, and osmium-toluidine blue staining showed no mineralization of the regenerated nerves in those tubes containing myelinated fibres after 9 weeks. PLGA tubes filled with DPCs promoted nerve regeneration and were readily resorbed in vivo.