The effect of hyperbaric oxygenation and hypoxia on the blood-nerve barrier.

We measured the permeability coefficient--surface area product (PA) of peripheral nerve to [14C]sucrose in rat sciatic nerve in experimental chronic hypoxic hypoxia of up to 8 weeks and following hyperbaric oxygenation for 1 to 4 weeks. Chronic hypoxia caused an increase in PA presumably indicating impairment of the blood-nerve barrier at 4 weeks with restoration to normal by 8 weeks. Hyperbaric oxygenation (100% oxygen at 2.5 ata for 120 min/day 5 days per week) caused a mild but time dependent increase in PA reaching statistical significance by 4 weeks.