EFFECT OF HYPERBARIC OXYGENATION ON PERIPHERAL-NERVE REGENERATION IN ADULT MALE RABBITS

Oxygen environments were used to study the regenerative effects of hyp erbaric oxygen on crushed sciatic nerves in 30 adult male rabbits. Six different oxygen environments were used, and treatments were initiate d 4 days post injury. Transmission electron microscopy and light micro scopy were used to evaluate the regenerative morphology of crushed ner ves. The morphology of crushed nerves after 7 wk of treatment with com pressed oxygen at 202, 242, and 303 kPa resembled normal uncrushed ner ves, with nerve fibers uniformly distributed throughout the section. T he treatment groups receiving 202 kPa compressed air, 100% normobaric oxygen, or ambient air did not display morphologies similar to normal uncrushed nerve. The nerves in these animals were edematous and contai ned disarrayed nerve fibers. Myelination in the animals receiving 100% O-2 at high pressures resembled undamaged nerves. Collagen and blood vessels were more evident in the lower pressure/oxygen tension treatme nts than in the animals receiving 100% O-2 at higher pressures. The ne urofilamentous material inside the crushed control axons was dense, wh ereas in the axons of animals treated with compressed O-2 it was loose ly packed. These differences in morphology suggest that treatments con sisting of 100% O-2, under pressure can accelerate a peripheral nerve' s recovery from a crush injury.