RESUMEN
PURPOSE: The aim of the present study was to determine the clinical, histologic, and histomorphometric influence of stem cells on the regeneration of facial nerves in rats submitted to neurotmesis with 5-mm defects. MATERIALS AND METHODS: Thirty-six male Wistar rats were submitted to neurotmesis. In group 1 (n = 18), the 2 extremities of the nerve trunk were sutured in a polyethylene tube containing a protein matrix (Matrigel; Invitrogen, BD Biosciences, Franklin Lakes, NJ). Group 2 (n = 18) underwent the same procedures with the incorporation of stem cells in the tube. The groups were subdivided by the day of euthanasia (30, 60, and 90 days). Evaluations of the central portion and distal extremity of the tubes were performed in both groups. RESULTS: During the functional evaluation, group 2 exhibited better closing of the eyelids at 30 and 60 days. The histomorphometric analyses revealed a significant reduction in the area of the nerve fibers in group 1 compared with group 2 at all 3 evaluation (P = .031). In group 2, the area of the nerve fibers was significantly greater (P = .031), and the thickness of the myelin sheath was significantly greater in the center (P = .002) and distal (P = .019) extremity of the tube at 30 days compared with the findings in group 1. CONCLUSIONS: The present findings suggest that the use of stem cells in nerve injuries will result in faster, more effective regeneration within the intervals analyzed.
