脊髓缺血损伤动物模型的建立

1、脊髓缺血损伤动物模型的建立 作者：管玉龙，刘锋，董培青，万彩红，杨璟 【摘要】 目的本研究拟建立胸降主动脉手术脊髓缺血动物模型，为脊髓保护策略和药物干预研究提供基础。方法实验中采用6只北京农大小型猪。经左侧第五肋间开胸，常温条件下在锁骨下动脉以远阻断降主动脉，30min后阻断开放。动物复苏后，对其下肢行为学临床评分每日进行观察。7日后处死动物取材，进行损伤区域脊髓超微结构观察。结果术中血液动力学平稳。血气结果均维持在正常范围。复苏后1只动物术后每天肌力均为IV 级，7天后处死时肌力IVV级；其余5只动物术后下肢肌力0 I级。电子显微镜超微结构观察显示脊髓较严重的损伤性改变。结论应用小型猪为动物

2、模型，在常温条件下胸降主动脉阻断30min，可以建立急性脊髓缺血术后截瘫模型。 【关键词】 脊髓；缺血；胸主动脉The Establishment of Porcine Model of Spinal Cord Ischemic InjuryAbstract: OBJECTIVE This study was designed to establish a porcine model of spinal cord ischemic injury produced by descending thoracic aorta occlusion and provide basis for strat

3、egy of spinal protection and pharmaceutical intervention. METHODSSix piglets were used in the experiments supplied by the Beijing College of Agriculture. A standard left thoracotomy was made through the fifth intercostals space. The descending aorta was clamped distal to left subclavian artery at no

4、rmothermia. Thirty minutes later, the clamps were released. The trachea was extubated once the animals recovered breathing spontaneously. The animals were evaluated daily according to a quantitative behavioral score. On postoperative seventh day the animals were sacrificed and histological analysis

5、for the injury of spinal cord was made. RESULTSHemodynamic data showed all animals were stable before, during and after the procedure. The results of behavioral scoring for each animal demonstrated one animal with paraparesis and other 5 animals with paraplegia. The injury of spinal cord was also de

6、monstrated by ultrastructural measurement.CONCLUSIONA porcine model of spinal cord ischemic injury can be established by descending thoracic aortic clamping thirty minutes at normothermia.Key words：Spinal cord；Ischemia；Thoracic aorta胸主动脉疾病实施外科治疗期间，围术期多种因素可能引起脊髓缺血，术后脊髓并发症一旦发生，直接影响手术效果和患者的生存质量。根据文献报告，

7、多以单纯阻断降主动脉30min为临床界定的安全时限。本研究对实验动物进行胸降主动脉阻断30min后随访观察，建立了脊髓缺血动物模型，可为进一步的脊髓保护策略和药物干预提供基础。1材料与方法1.1实验动物6只北京农大小型猪，体重20 kg25.9 kg，雌性，在实验前12 h禁食，4 h禁水。1.2麻醉基础1.3手术方法动物右侧卧位，经肩胛骨下方第五肋间隙横行皮肤切口，切口长度约15cm。逐层切开皮下组织，暴露胸腔。探查降主动脉的部位，并仔细分离锁骨下动脉以远0.5cm1cm区域降主动脉外膜，4.0手术线缝置荷包，分离其下方远心端0.5cm区域降主动脉，套阻断带作为第一阻断平面。在降主动脉第一阻

8、断平面部位以远4cm5cm 处进行第二处分离，同样套阻断带和缝置荷包，作为第二阻断平面。在第一荷包和第二荷包分别插套管针，连接三通，进行压力测定和取血。待第一、第二阻断平面阻断带放置完成后，体内给肝素150IU/kg。首先在第一阻断平面使用阻断钳阻断降主动脉血流，阻断期间密切观察血压变化，必要时给予一定的扩血管药物。继续使用第二把阻断钳阻断第二平面降主动脉血流（见图1）。阻断30min后开放阻断钳，顺序是先开放远心端阻断钳，后开放近心端阻断钳。鱼精蛋白中和体内肝素（比例11）。1.4监测指标2结果2.1血液动力学术中血液动力学平稳，阻断前血压维持在100120 mm Hg，心率120140次/min。在阻断后近心端血压明显上升，心率先加快后减慢，给予药物降压处理维持在90100次/min。远心端血压20 mm Hg。开放后血压较术前有一定的下降，但没有统计学意义。2.2血细胞手术期间动物血细胞压积和血色素轻度下降，7天后处死时基本恢复正常。2.3温度手术期间肛温变化不明显，术前为36.537，阻断期间肛温35.536，手术结束时肛温3636.5。2.4下肢行为学动物术前上下肢肌力均为V级，阻断30 min术后动物顺利清醒拔除气管插管，上肢肌力恢复