脑死亡状态巴马小型猪肺水含量及肺超微结构变化

Changes of lung water content and ultrastructure in bama miniature pigs under brain death status

目的：观察脑死亡状态下巴马小型猪肺水含量及肺组织常规及超微结构改变。方法：实验于2003-08/2004-12在河南省实验动物中心及河南省病理学重点实验室完成。选用健康巴马小型猪11只,采用随机数字表法随机分为2组,对照组5只,脑死亡组6只。对照组持续麻醉维持24h,不建立脑死亡模型,24h后撤除麻醉,动物苏醒后处死;脑死亡组6只,应用改进的缓慢间断颅内加压法建立脑死亡模型,判定脑死亡后通过呼吸、循环支持维持动物脑死亡状态24h,24h后撤除呼吸、循环支持,动物心肺死亡。维持脑死亡状态下巴马小型猪的生命体征达到脑死亡供体要求,即平均动脉压≥60mmHg（1mmHg=0.133kPa）,血氧饱和度≥95%,血氧分压≥100mmHg,体温≥35℃,中心静脉压≤10-12mmHg,血流动力学稳定。观察脑死亡组动物脑死亡24h后肺组织肺水含量、肺脏常规组织形态（光镜,苏木精-伊红染色）及超微结构变化（电镜）,并与对照组比较。结果：脑死亡组1只动物在脑死亡造模过程中因心肺死亡脱失。①两组动物肺水含量比较：脑死亡组肺水含量显著高于对照组[（0.83±0.00,0.76±0.02）g/g（P〈0.05）]。②两组动物肺脏常规组织形态及超微结构变化：脑死亡组动物肺组织光镜下见肺间质弥漫性水肿,肺泡间隔增宽,肺泡腔有渗出液,局灶性肺不张,肺毛细血管充血;电镜下可见肺泡Ⅱ型上皮细胞线粒体肿胀,线粒体嵴存在排列紊乱、消失,微绒毛缺失,板层小体数量减少、脱颗粒,结构有破坏。对照组光镜及电镜下未见明显的损伤性变化。结论：脑死亡状态可导致肺水含量增加,肺组织出现损伤性改变,可能对移植后肺组织功能造成一定影响。

AIM： To investigate the changes of lung water content, routine of lung tissues and ultrastructure in bama miniature pigs in the state of brain death. METHODS： The experiment was performed at the Henan Experimental Animal Center and Henan Key Laboratory of Pathology from August 2003 to December 2004. Totally 11 healthy bama miniature pigs were selected and randomly divided into 2 groups： control group （n =5） and brain death group （n =6）. Control group was maintained anesthesia for 24 hours, but not created brain death model. Twenty-four hours later, anesthesia was removed, and the animals were killed after analepsia. Six pigs in the brain death group were used to establish brain death models by modified slow intermittent intracranial pressure. Brain-death state was maintained for 24 hours by respiration and circulation support. The heart and lung were out of work after removing respiration and circulation support. When the mean artery pressure （MAP） ≥ 60 mm Hg （1 mm Hg=0.133 kPa）, saturation of blood oxygen （SPO2）≥ 95%, （partial pressure of oxygen） PaO2 ≥ 100 mm Hg, body temperature ≥ 35 ℃, central venous pressure （CVP） ≤ 10-12 mm Hg, and hemodynamic was stable, the brain-death models ware considered suitable as the brain-death donor. Twenty-four hours after the initial brain death, lung water content, routine morphology （light microscope, HE staining） and ultrastructure changes of lung tissues （electron microscope） were observed and compared with the control group. RESULTS： One in the brain death group was dropped out, because of the death of heart and lung in establishing models, and 10 pigs were involved in the result analysis, 5 in each group. ①Comparison of lung water content in the two groups： It was significantly higher in the brain death group than the control group [（0.83±0.00,0.76±0.02） gig （P 〈 0.05）]. ②Changes of routine morphology and ultrastructure changes of lung tissues in the two groups： In the brain death group by light microscope, interstitial diffuse pulmonary edema, broadened lung alveolar septum, effusion from alveolar space, focal atelectasis and engorgement of pulmonary capillary, under electron microscope mitochondria of the type-Ⅱ epithelial cells swelled, the mitochondria cristae fragmented and disappeared, microvilli deleted, lamellar bodies in alveolar type-Ⅱ epithelial cells reduced and was degranuled and their structures were destroyed. In the control group, lung tissues appearances ware normal under light microscope and electron microscope. CONCLUSION： Brain death may increase lung water content and injured change appears in lung tissues, which may have a certain effect on function of lung tissues after transplantation.