中文摘要：

目的：探讨海水淹溺性肺水肿与肺钠钾-ATP酶的关系及不同剂量地塞米松对其影响。方法：将40只家兔随机分为4组：对照组（CG）、海水淹溺组（SG）和不同剂量地塞米松治疗组（DG1：0.2mg/kg、DG2：1mg/kg）。SG组兔给予气管内灌注3ml/kg海水,DG1、DG2组在CG组的基础上分别静注0.2mg/kg、1mg/kg地塞米松。于淹溺前及淹溺后30min、60min、120min进行动脉血气分析,淹溺后120min测定肺湿/干重比、肺泡通透指数及钠钾-ATP酶,观察各组兔肺脏在治疗前后光镜、电镜下的改变并计算肺损伤病理评分。结果：与SG组比较,DG1、DG2组在淹溺后60min、120min PO2明显升高（P〈0.01）,在淹溺后120min肺湿/干重比、肺泡通透指数及肺损伤病理评分明显下降（P〈0.05）,但DG1组与DG2组之间比较无显著性差异（P〉0.05）。使用地塞米松干预后,DG1、DG2组钠钾-ATP酶活性明显增高,与CG及SG组比较均有明显差异（P〈0.05）。从形态学上观察,SG,DG1及DG2组动物均可见肺毛细血管淤血,肺泡型、型上皮细胞受损,但SG组动物损伤相对较重。结论：地塞米松可改善兔海水淹溺性肺水肿的缺氧及减轻肺水肿,但增加剂量（1mg/kg）并不能增加治疗效果,其机制可能与地塞米松上调肺组织钠-钾-ATP酶有关。

英文摘要：

Objective：To investigate the relationship between pulmonary edema of seawater drowning（PE-SWD）and Na＋-K＋-ATP ase in rabbits and the therapeutical effect of dexamethasone with different doses.Methods：40 rabbits were randomly divided into 4 groups：control group（CG）,seawater drowning group（SG）,dexamethasone groups（0.2mg/kg as DG1,1.0 mg/kg as DG2）,with 10 in each group.Seawater（3ml/kg body weight） were instilled into the lower trachea of rabbits in SG,DG1 and DG2.These rabbits were assigned randomly to receive injection of 2ml of saline（SG） or 0.2mg/kg（DG1）,1mg/kg（DG2） weight of dexamethasone.Arterial blood gas analysis were measured before and after 30min,60min and 120min seawater drowning.The ratio of lung wet/dry weight,lung permeability index and the Na＋-K＋-ATPase activity were determind by the end of the study.The patho-histological changes of lungs were investigated by microscope and electroscope.Results：Compared with SG,the PO2 in DG1 and DG2 increased significantly（P〈0.01）after 60min and 120min seawater drowning,while the contents of lung water and lung permeability index in DG1 and DG2 were decreased（P〈0.05）.There was no significant difference（P 0.05）between DG1 were DG2.After administration of dexamethasone,the Na＋-K＋-ATPase activity in DG1 and DG2 was significantly increased thanthose in CG and SG（P 0.05）.Morphological changes,such as the congestion of pulmonary capillary and damages of the pulmonary alveolar typesⅠandⅡcells,can be observed by microscope and electroscope.The morphological changes of lungs were more serious in SG.Conclusion： Dexamethasone can improve hypoxia of PE-SWD in rabbits and attenuate lung edema.However,high dose（1mg/kg）can not improve the treatment effect.The difference in therapeutic effect produced by different doses of dexamethasone may be associated with up-regulation of the Na＋-K＋-ATPase activity.