胸主动脉阻断联合主动脉旁路循环技术建立大鼠脊髓缺血损伤模型

目的 改良大鼠脊髓缺血损伤动物模型。方法 大鼠分为3组：实验组，阻断胸主动脉（T4-T11）+主动脉旁路循环（胸主动脉起始部-胸主动脉近膈肌部），阻断20 min；对照组，阻断胸主动脉（T4）20 min；假手术组，只开胸不阻断胸主动脉。术中采用经颅运动诱发电位（Tc-MEP）监测脊髓功能，术后7 d观察脊髓切片病理改变；采用BBB评分评估脊髓功能，28 d分析大鼠生存曲线。结果 实验组Tc-MEP波形6 min后消失，对照组8 min后Tc-MEP波形消失，直至手术结束。脊髓切片显示实验组神经元大量变性坏死，对照组多个神经元坏死。实验组比对照组BBB评分下降明显；28 d生存率差异有统计学意义（P <0.05）。结论 胸主动脉阻断+主动脉旁路循环方法，对比传统的胸主动脉阻断方法，效果确切，存活率高。

Establishment of Spinal Cord Ischemia Injury Model in Rats by Thoracic Aorta Occlusion Combined with Aortic Bypass

  Objective  To modify the rat model of spinal cord ischemia injury.   Methods  The rats were divided into three groups. In experimental group, thoracic aorta was cross-clamped between T4 and T11, and aortic bypass circulation was established from proximal thoracic aorta to proximal diaphragmatic aorta. The interval of clamping was 20 minutes. In control group, the thoracic aorta （T4） was cross-clamped for 20 minutes.In the sham operation group, only thoracotomy was performed without thoracic aorta cross-clamping. Thefunction of spinal cord was monitored by transcranial motor evoked potential （TC-MEP）. The pathology of spinal cord were observed 7 days after surgery. The locomotor function of spinal cord was evaluated by BBB score at multiple postoperative time. The survival curves were analyzed 28 days after operation.   Results  The TC-MEP waveform of the experimental group disappeared after 6 minutes, and that of the control group disappeared after 8 minutes until the end of surgery. The slices of spinal cord showed a large number of degeneration and necrosis of neurons in the experimental group. Multiple neurons were necrotic in the control group. The BBB score of the experimental group decreased more obviously than that of the control group. There was a significant difference in the 28-day survival rate between the experimental group and the control group, and （P < 0.05）.   Conclusion  Thoracic aortic cross-clamping plus aortic bypass is an effective method, with high long-term survival rate.