Hyperbaric oxygen pretreatment benefits on decompression sickness in Bama pigs

Abstract

Decompression sickness (DCS) occurs when ambient pressure severely reduces during diving and aviation. Hyperbaric oxygen (HBO) pretreatment has been proven to exert beneficial effects on DCS in rats via heat-shock proteins (HSPs). We hypothesize that HBO pretreatment will also reduce DCS via HSPs in swine models. In part 1, six swine were subjected to a session of HBO treatment. HSP 32, 60, 70 and 90 were detected, before and at 6, 12, 18, 24 and 30 h following exposure in lymphocytes. In part 2, another ten swine were randomly assigned into 2 groups, 5 in each. All swine were subjected to two simulated air dives in a hyperbaric chamber with an interval of 7 days. Eighteen hours before each dive, the swine were pretreated with HBO or air. Five swine in the first group received air pretreatment prior to the first dive and HBO pretreatment prior to the second. The other 5 swine in the second group pretreated with HBO first and then air. Bubble loads, skin lesions, inflammation and endothelial markers were detected after each dive. In lymphocytes, all HSPs increased significantly (P<0.05) with the greatest expression appearing at 18 h for HSP 32 and 70. HBO pretreatment reduced significantly all the determined changes compared with air pretreatment. The results demonstrate that a single exposure to HBO 18 h prior to diving effectively protects against DCS in the swine model, possibly via induction of HSPs.