Establishment of a rat model of decompression sickness induced by simulated deep fast buoyancy ascent of submariners

Abstract

Objective To establish a rat model of decompression sickness induced by simulated deep fast buoyancy ascent of submariners.Methods Eighty male SD rats were randomly divided into 4 groups,each consisting of 20 animals:the control group,the 2-min exposure group,the 4-min exposure group,and the 8-min exposure group.The latter 3 groups were compressed to 150 m at an exponential rate of 2 t/8s in the air chamber,stayed at the said pressure respectively for 2,4 and 8 mins.Then,they were decompressed to atmospheric pressure at a linear speed of 3 m/s.Behavior and pathological changes in lungs,brain,spinal cord of all the animal groups were closely observed.Results After they came out of the chamber,the animals of all the groups displayed the following behaviors:hair erection,scratching and slow reaction.Pathological examination indicated that there were edema and hemorrhage in the alveolar and pulmonary interstitial tissue,and in the spinal cord as well.However,no significant pathological changes in the brain tissue could be noted.Mobidity of 2,4,8-min profile SD rats were 20.07％,55.0％ and 10.0％,respectiuely,At the same time,mortality of which were 0,20.0％ and 85.0％,respectively.Significant differences could also be seen in the morbidity and mortality of the animals in various exposure groups with different exposure time(P＜0.01).As the exposure time of the 8-min profile was too long,mortality 3 of the developed rat model was relatively higher,when they came out of the chamber.Nevertheless,the exposure time of the 2-min profile was obviously inadequate,morbidity of the developed rat model was relatively lower.Thus,the 4-min profile with a low mortality and high morbidity of decompression sickness might be appropriate for submarine escape.Conclusions The experiment has successfully established 4-min exposure profile was the animal model of decompression sickness induced by deep fast buoyancy ascent of submariners. Key words: Fast buoyancy ascent escape; Decompression sickness; Animal model