目的 评价长时间深低温低流量体外循环(cardiopulmonary bypass, CPB)心脏手术对幼猪未成熟脑的影响及其机制。方法 北京长白幼猪15例，按随机数字表法分为实验组（10只）和对照组（5只）。实验组麻醉后正中开胸，常规建立CPB，体温降至25 ℃后，开始低流量循环（50 ml•kg-1•min-1），主动脉阻断120 min后开放，停机后观察120 min取脑海马组织；对照组麻醉后开胸，取脑海马组织。实验组分别在麻醉诱导后即刻（T1）、停机后5 min（T2）、120 min（T3）取静脉血，酶联免疫吸附法（ELISA）检测白细胞介素-6（interleukin-6, IL-6）、肿瘤坏死因子-α（tumor necrosis factor-α, TNF-α）。实验组、对照组脑海马组织行HE染色病理检查；ELISA法测海马神经元特异性烯醇化酶（neuron-specific enolase, NSE）、S100蛋白β亚型（S100 protein beta subtypes, S100β）。结果 实验组1只死于CPB停机后心脏骤停，余9只和对照组5只完成至实验结束。与T1比较，实验组T2的IL-6、TNF-α分别升高7.01%（P <0.05）、3.52%（P <0.05）；T3的IL-6、TNF-α分别升高5.10%（P <0.05）、1.47%（P >0.05）。与对照组比较，实验组可见脑损伤病理学改变，NSE、S100β分别升高40.08%（P <0.05）、29.66%（P<0.05）。结论 深低温低流量CPB心脏手术可造成幼猪脑组织损伤，并证实炎症反应是脑损伤的可能机制之一。
Objective To evaluate the effect and mechanisms of prolonged deep hypothermic low-flow cardiopulmonary bypass (CPB) cardiac surgery to the immature brain on piglets. Methods 15 Beijing Landrace piglets were divided into study group (n=10) and control group (n=5). Routine CPB was established after median thoracotomy in study group under anesthesia. Low-flow CPB（50 ml•kg-1•min-1）was started when the temperature of the animal dropped down to 25 ℃. The aorta was reopened after 120 min cross-clamping. Brain hippocampus tissues were harvested after 120 min following CPB ceased. In control group, hippocampus tissues were harvested after median thoracotomy under anesthesia. In study group, venous blood samples were taken immediately after anesthesia induction (T1), 5 min (T2) and 120 min (T3) after the CPB shutdown, and interleukin (IL)-6, tumor necrosis factor (TNF)-α were tested through enzyme-linked immunosorbent assay (ELISA). In both groups, HE staining for pathological examination of brain hippocampus tissues was adopted; and hippocampus tissues homogenates, contents of neuron-specific enolase (NSE), S100 protein β subtypes (S100β) were detected by ELISA method. Results 1 piglet from study group was died by heart arrest after CPB; the other 9 piglets in study group and all 5 in control group completed to the end of the experiment. In study group, compared with T1, IL-6, TNF-α were increased by 7.01%(P <0.05),3.52%(P <0.05)in T2, and by 5.10%(P <0.05)、1.47%(P >0.05)in T3. Compared with control group, study group showed pathological changes of brain damage, and NSE, S100β were also increased by 40.08%(P <0.05)、29.66%(P <0.05). Conclusions Deep hypothermic low-flow CPB would result in brain injury on piglets and its key mechanism might be inflammatory injury.
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