减压病大鼠模型心脏血流动力学的改变

Changes of cardiac hemodynamics in rats with decompression sickness

目的探究减压病大鼠模型心脏血流动力学的变化。方法选择15只雄性SD大鼠,进舱前行心脏彩超检测作为正常对照数据。将动物置于加压舱内,以21/4指数方案快速加压至1.5 MPa后停留242 s,再以3 m/s的速度匀速减压50 s。出舱后观测动物减压病症状,统计减压病发病率及生存率。对存活动物进行心脏彩超检测后,取正常对照组、死亡组及减压后存活组动物的心肺组织进行病理分析。结果15只动物均出现呼吸急促、懒动等减压病症状,9只在减压后30 min内死亡。其中4只于出舱后1 min内死亡,未检测到数据。减压后死亡组大鼠肺组织呈现显著肺水肿、出血及结构破坏,心肌组织显示纤维断裂、水肿。而减压后存活组大鼠的心肺组织损伤明显减轻。与进舱前及减压后存活大鼠相比,减压病死亡大鼠左心室收缩末期容积显著增加,左心室射出分率显著降低(P<0.05),心腔及心肌细胞内可见大量气泡,肺水肿显著。减压后存活组大鼠左心室每搏输出量及每分输出量呈上升趋势,与死亡组相比明显增加(P<0.05),与正常组相比无统计学意义。结论心脏血流动力学障碍引起的心肺损伤是导致快速上浮脱险减压病大鼠死亡的重要原因。

Objective To explore the changes of cardiac hemodynamics in rats with decompression sickness.Methods Fifteen male SD rats were examined by color Doppler echocardiography before entering the cabin in order to obtain the normal control data.Rats were put in the pressurized cabin that was quickly pressurized to 1.5 MPa with 21/4 exponential scheme.These rats stayed in the cabin for 242 s before being decompressed to 0 m at 3 m/s.The total decompression time was 50 s.After the rats left the cabin,their morbidity was observed.Lung and heart tissues were collected,and the pathology was analyzed with HE staining.The survivors were detected by Doppler echocardiography.Results All the 15 rats developed symptoms of decompression sickness,such as shortness of breath and laziness.Nine died within 30 min after decompression.Four of them died within 1 min and no data was available.After decompression,the lung tissue of rats in the death group showed significant edema,hemorrhage,and structural damage.Myocardial tissue showed fiber breakage and edema.However,the cardiopulmonary tissue injury in the survival group was significantly less severe.Compared with the control data and data from the surviving rats,the left ventricular end-systolic volume of rats that died of decompression sickness was significantly increased(P<0.05).A large number of bubbles were observed in the cardiac cavity and in myocardial cells and left ventricular ejection fraction decreased significantly.Pulmonary edema was observed in the death group(P<0.05).Conclusion Cardiac hemodynamic disorder is an important cause of death in rats with rapid buoyancy and decompression sickness.