目的 研究高位脊髓损伤（spinal cord injury， SCI）后氯胺酮（ketamine， KT）对循环系统紊乱的保护作用。 方法 健康雄性SD大鼠20只，通过抽签将大鼠随机分为单纯SCI组（SCI组）、SCI后给予KT治疗组（SCI+KT组）、对照组（Sham组）和对照给予KT治疗组（Sham+KT组），每组5只。SCI大鼠采用改良Allens打击法建立脊髓胸4节段损伤动物模型，Sham组仅咬除椎板，未打击脊髓。SCI+KT组和Sham+KT组分别在手术处理后24 h开始给予KT腹腔注射1 mg·kg-1·d-1。观察处理前后1周~6周大鼠平均动脉压（mean arterial pressure， MAP）、心率（heat rate， HR）、24 h尿中去甲肾上腺素（noradenaline， NA）的变化，以及6周后大鼠左心室内压变化最大速率（left ventricular internal pressure maximum rate of change， ±dp/dtmax）和苏木精-伊红（hematoxylin and eosin， HE）心肌染色的变化。 结果 术后1周SCI组大鼠MAP为（90±4） mmHg（1 mmHg=0.133 kPa），较Sham组明显降低，同时伴有HR增至（518±11） 次/min、尿中NA减少、6周后左心室内压最大上升速率（left ventricular internal pressure maximum rising rate， +dp/dtmax）增大、心肌纤维化明显（P＜0.05）；SCI+KT组较SCI组MAP升高至（106±4） mmHg、HR下降到（459±10） 次/min、尿中NA增多、6周后+dp/dtmax减小、心肌纤维化程度明显减轻（P＜0.05）。 结论 SCI后使用KT可以改善血流动力学指标，从而改善大鼠心肌收缩力，减轻心肌细胞损伤，而这种作用可能是通过增加机体NA含量实现的。
Ｏｂｊｅｃｔｉｖｅ To study the protective effect of ketamine（KT） on circulatory system disorders after high-level spinal cord injury（SCI） in rats. Methods Twenty male 18-week-old SD rats weighing 290 g-310 g were randomly divided into 4 groups（n=5）： SCI group， SCI+KT group， Sham group and Sham+KT group. The animals in SCI and SCI+KT groups were subjected to SCI at T4 according to modified Allen′s method. The operations for Sham group and Sham+KT group were preformed without stroking spinal cord. Twenty-four hours after the operation， SCI+KT group and Sham+KT group were treated with ketamine 1 mg·kg-1·d-1， daily lasting 6 weeks. Mean arterial pressure（MAP）， heat rate（HR） and the level of noradenaline（NA） in urine were recorded once a week for 6 weeks. At the end of 6 weeks post operation， left ventricular internal pressure maximum rate of change（±dp/dtmax） were recorded and myocardial specimen was sampled from left ventricle to study myocardial histology with HE staining. Results In SCI group， the animal's MAP［（90±4） mmHg（1 mmHg=0.133 kPa）］ and NA level were significantly lower and HR［（518±11） bpm］ were significantly faster starting from 1 week post SCI compared with Sham group. Left ventricular internal pressure maximum rising rate（+dp/dtmax） were significantly increased 6 weeks post SCI. However， in SCI+KT group， the animals′ MAP increased to （106±4） mmHg， HR decreased to （459±10） bpm， and +dp/dtmax and NA lever changed significantly（P＜0.05）. Ultrastructure Of myocardial tissue presented abnormal changes in SCI groups，but the changes in SCI+KT group were milder． Conclusions High-level spinal cord injury could induce the disorders of circulatory system. Ketamine can increase NA lever and improve hemodynamics and myocardial function after SCI．
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