脊髓缺血損傷動物模型的建立

1、脊髓缺血損傷動物模型的建立 作者：管玉龍，劉鋒，董培青，萬彩紅，楊璟 【摘要】 目的本研究擬建立胸降主動脈手術脊髓缺血動物模型，為脊髓保護策略和藥物干預研究提供基礎。方法實驗中采用6只北京農(nóng)大小型豬。經(jīng)左側第五肋間開胸，常溫條件下在鎖骨下動脈以遠阻斷降主動脈，30min后阻斷開放。動物復蘇后，對其下肢行為學臨床評分每日進行觀察。7日后處死動物取材，進行損傷區(qū)域脊髓超微結構觀察。結果術中血液動力學平穩(wěn)。血氣結果均維持在正常范圍。復蘇后1只動物術后每天肌力均為IV 級，7天后處死時肌力IVV級；其余5只動物術后下肢肌力0 I級。電子顯微鏡超微結構觀察顯示脊髓較嚴重的損傷性改變。結論應用小型豬為動物

2、模型，在常溫條件下胸降主動脈阻斷30min，可以建立急性脊髓缺血術后截癱模型。 【關鍵詞】 脊髓；缺血；胸主動脈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胸主動脈疾病實施外科治療期間，圍術期多種因素可能引起脊髓缺血，術后脊髓并發(fā)癥一旦發(fā)生，直接影響手術效果和患者的生存質量。根據(jù)文獻報告，

7、多以單純阻斷降主動脈30min為臨床界定的安全時限。本研究對實驗動物進行胸降主動脈阻斷30min后隨訪觀察，建立了脊髓缺血動物模型，可為進一步的脊髓保護策略和藥物干預提供基礎。1材料與方法1.1實驗動物6只北京農(nóng)大小型豬，體重20 kg25.9 kg，雌性，在實驗前12 h禁食，4 h禁水。1.2麻醉基礎1.3手術方法動物右側臥位，經(jīng)肩胛骨下方第五肋間隙橫行皮膚切口，切口長度約15cm。逐層切開皮下組織，暴露胸腔。探查降主動脈的部位，并仔細分離鎖骨下動脈以遠0.5cm1cm區(qū)域降主動脈外膜，4.0手術線縫置荷包，分離其下方遠心端0.5cm區(qū)域降主動脈，套阻斷帶作為第一阻斷平面。在降主動脈第一阻

8、斷平面部位以遠4cm5cm 處進行第二處分離，同樣套阻斷帶和縫置荷包，作為第二阻斷平面。在第一荷包和第二荷包分別插套管針，連接三通，進行壓力測定和取血。待第一、第二阻斷平面阻斷帶放置完成后，體內給肝素150IU/kg。首先在第一阻斷平面使用阻斷鉗阻斷降主動脈血流，阻斷期間密切觀察血壓變化，必要時給予一定的擴血管藥物。繼續(xù)使用第二把阻斷鉗阻斷第二平面降主動脈血流（見圖1）。阻斷30min后開放阻斷鉗，順序是先開放遠心端阻斷鉗，后開放近心端阻斷鉗。魚精蛋白中和體內肝素（比例11）。1.4監(jiān)測指標2結果2.1血液動力學術中血液動力學平穩(wěn)，阻斷前血壓維持在100120 mm Hg，心率120140次/min。在阻斷后近心端血壓明顯上升，心率先加快后減慢，給予藥物降壓處理維持在90100次/min。遠心端血壓20 mm Hg。開放后血壓較術前有一定的下降，但沒有統(tǒng)計學意義。2.2血細胞手術期間動物血細胞壓積和血色素輕度下降，7天后處死時基本恢復正常。2.3溫度手術期間肛溫變化不明顯，術前為36.537，阻斷期間肛溫35.536，手術結束時肛溫3636.5。2.4下肢行為學動物術前上下肢肌力均為V級，阻斷30 min術后動物順利清醒拔除氣管插管，上肢肌力恢復