Bubble-induced platelet aggregation in a rat model of decompression sickness

Pontier JM, Vallee N, Bourdon L. Bubble-induced platelet aggregation in a rat model of decompression sickness. J Appl Physiol 107: 1825-1829, 2009. First published October 22, 2009; doi:10.1152/japplphysiol.91644.2008.-Previous studies have highlighted that bubble-induced platelet aggregation is a predictor index of decompression sickness (DCS) severity in animals and bubble formation after a single air dive in humans. The present study attempted to investigate plasmatic indexes of the coagulation system and platelet activation in our rat model of DCS. Male Sprague-Dawley rats were assigned to one experimental group with a hyperbaric exposure and one control group maintained at atmospheric pressure. Rats were compressed to 1,000 kPa (90 m saltwater) for 45 min while breathing air. The onset of death time and DCS symptoms were recorded during a 30-min observed period after rats had surfaced. Plasmatic indexes were platelet factor 4 (PF4) for platelet activation, soluble glycoprotein V (sGPV) for thrombin generation, and thrombin-antithrombin complexes for the coagulation system. Blood samples for a platelet count and markers were taken 3 wk before the experimental protocol and within the 30 min after rats had surfaced. We confirmed a correlation between the percent fall in platelet count and DCS severity. Plasmatic levels of sGPV and PF4 were significantly increased after the hyperbaric exposure, with no change in the control group. The present study confirms platelet consumption as a potential index for evaluating decompression stress and DCS severity. The results point to the participation of thrombin generation in the coagulation cascade and platelet activation in bubble-induced platelet aggregation. In our animal model of DCS, the results cannot prejudge the mechanisms of platelet activation between bubble-induced vessel wall injury and bubble-blood component interactions.