Mesenchymal Bone Marrow Stem Cells, Integrated in Neural Tissue 6 Weeks after Implantation within Polyglycolic Acid Tube, Improved Facial Nerve Regeneration

Introduction: This study highlighted the importance of good scaffolds to maintain implanted cells alive for a longer period, extending their beneficial effects in the place required. Autografts associated with high-quality scaffolds and cell implants have disclosed distinct experimental outcomes for facial nerve repair with tissue loss.

Objective: To evaluate the functional and histological effects of bone marrow stem cells (BMSC) combined with polyglycolic acid tube (PGAt) in autografted rat facial nerves.

Methods: After neurotmesis of the mandibular branch of the rat facial nerve, surgical repair consisted of nerve autografting (groups A-E) contained in PGAt (groups B-E), filled with basement membrane matrix (groups C-E) with undifferentiated BMSC (group D) or Schwann-like cells that had differentiated from BMSC (group E). Axon morphometrics and compound muscle action potentials (CMAP) analyses were conducted. Immunofluorescence assays were made with Schwann cell marker S100 and anti-B-galactosidase to label exogenous cells.

Results: Six weeks after surgery, animals from either cell-containing group had mean CMAP amplitudes significantly higher than control groups. Schwann-like cell implants had the highest mean axonal diameter in distal segments. We observed expression of the reporter gene lacZ in nerve cells in the graft and distally from it in groups D and E. Group E cells had lacZ co-expressed with S100.

Conclusion: Regeneration of the facial nerve was improved by BMSC within PGAt in rats, yet Schwann-like cells were associated with superior effects. Groups D and E had BMSC integrated in neural tissue with maintenance of former cell phenotype for 6 weeks.