Microparticle-induced vascular injury in mice following decompression is inhibited by hyperbaric oxygen: effects on microparticles and interleukin-1β

Hyperbaric oxygen (HBO2) became a mainstay for treating decompression sickness (DCS) because bubbles are associated with the disorder. Inflammatory processes including production of circulating microparticles (MPs) have now been shown to occur with DCS, leading to questions regarding pathophysiology and the role for HBO2. We investigated effects of HBO2 on mice exposed to 790 kPa air pressure for 2 hours, which triggers elevations of MPs ladened with interleukin (IL)-1β that cause diffuse vascular injuries. Exposure to 283 kPa O2 (HBO2) inhibited MPs elevations at 2 hours post-decompression by 50% when applied either prophylactically or as treatment after decompression; and MPs number remained suppressed for 13 hours in the prophylactic group. Particle content of IL-1β at 2 hours post-decompression was 139.3 + 16.2 (mean + SE, n=11, p<0.05) pg/million MPs, versus 8.2 + 1.0 (n=15) in control mice; whereas it was 31.5 + 6.1 (n=6, not significant vs control [NS]) in mice exposed to HBO2 prophylactically, and...