Hyperbaric oxygen treatment after rat peroneal nerve transection and entubulation.

Rat peroneal nerves were transected and entubulated with a Silastic channel. The experimental group was treated with hyperbaric oxygen to evaluate changes in acute edema, functional recovery, and histology. Hyperbaric oxygen was administered with 100% O2 at 2.5 atmospheres absolute for 90 minutes twice a day for 1 week and then four times a day for 1 week. Acute edema changes based on nerve water weight and transfascicular area measurements were greater in injured than in uninjured nerves but demonstrated no differences between hyperbaric oxygen-treated and -untreated groups 2, 8 and 16 days after surgery. Functional evaluation with gait analysis demonstrated significant changes between injured and uninjured group 1, 3, 7, and 13 weeks after injury but no differences between hyperbaric oxygen-treated and -untreated groups. Thirteen weeks after the initial injury, elicited muscle force measurements demonstrated no significant improvement from hyperbaric oxygen treatment of injured nerves. Histologic evaluation of nerve area, myelinated axon number, myelinated axon area, myelin thickness, and blood vessel number and area revealed no significant differences between hyperbaric oxygen-treated and -untreated groups. Hyperbaric oxygen was not associated with improvement of nerve regeneration with any of the outcome variables in this model.