The effect of different application timings of hyperbaric oxygen treatment on nerve regeneration in rats

Background The aim of the study was to determine the effect of different application timings of hyperbaric oxygen treatment (HBO) on nerve regeneration in rats. Materials and Methods A total of forty 12‐week‐old female Wistar albino rats were used. The sciatic nerve was transected. The nerve ends were then realigned and repaired using standard microsurgical techniques. Animals were randomly assigned to four groups: 1) No hyperbaric oxygen, sectioned and repaired; 2) HBO started at postoperative first hour, sectioned and repaired; 3) HBO started at postoperative first week, sectioned, and repaired; and 4) HBO started at postoperative second week, sectioned, and repaired. All rats in all groups were evaluated with gait analysis at 8 and 16 weeks postoperatively. Sciatic function index was calculated. Sciatic nerve samples were taken after gait analysis at 16th week. Foreign body reaction, the intensity of the inflammatory cells and types, repair‐associated vascular proliferation in the field, axonal vacuolar degeneration of the fibers from the cut line transition density and switching layout, and myelinization density with perineural sheath were evaluated histopathologically. Results At the 16th week, group 2 demonstrated the best gait analysis results. Gait analysis was better for group 3 than groups 1 and 4 (P 0.05). Fibrosis was statistically less in group 2 than that in other groups (P 0.05). Conclusions Our results suggest that initiating HBO early after nerve repair will make a positive impact on recovery. © 2016 Wiley Periodicals, Inc. Microsurgery 36:586–592, 2016.