Effects of hyperbaric oxygen therapy on facial nerve regeneration.
CONCLUSIONS
Hyperbaric oxygen treatment (HBOT) promoted an increase of the mean axonal diameter in the group evaluated 2 weeks after lesion induction, which suggests a more advanced regeneration process. However, the number of myelin nerve fibers of the facial nerve of the rabbits was similar when compared to the control and treatment groups, in both evaluation periods.


OBJECTIVE
To evaluate the effect of HBOT on the histological pattern of the facial nerve in rabbits exposed to a nerve crush injury.


METHODS
Twenty rabbits were exposed to facial nerve crush injury. Ten rabbits received HBOT, 10 rabbits comprised the control group. The rabbits were sacrificed 2 and 4 weeks after the trauma. Qualitative morphological analysis, measurement of the external axonal diameters and myelin fiber count were carried out in an area of 185 000 microm2.


RESULTS
There was an increase in the area of the axons and thicker myelin in the 2 weeks treatment group in comparison with the control group. The mean diameter of the axons was of 2.34 microm in the control group and of 2.81 microm in the HBOT group, with statistically significant differences. The 2 week control group had a mean number of myelin fibers of 1865.2 +/- 664, and the HBOT group had a mean number of 2026.3 +/- 302; this was not statistically significant. The 4 week control group presented a mean of 2495.1 +/- 479 fibers and the HBOT group presented a mean of 2359.9 +/- 473; this was not statistically significant.
Vilela
Daniela Salgado Alves
DS
Otorhinolaryngology Department, Santa Casa São Paulo, Faculty of Medical Sciences, São Paulo, Brazil. ceotorrino@santacasasp.org.br
Lazarini
Paulo Roberto
PR
Da Silva
Ciro Ferreira
CF
D000818:Animals; D001369:Axons / Q000473:pathology / Q000502:physiology; D005154:Facial Nerve / Q000473:pathology / Q000503:physiopathology; D020220:Facial Nerve Injuries / Q000473:pathology* / Q000503:physiopathology / Q000628:therapy*; D006931:Hyperbaric Oxygenation; D008297:Male; D009186:Myelin Sheath / Q000473:pathology / Q000502:physiology; D009409:Nerve Crush; D009416:Nerve Regeneration; D011817:Rabbits; D013997:Time Factors