不同深低温停循环方法对脑组织S-100蛋白表达的影响

目的观察不同深低温停循环方法对脑组织S—100蛋白表达及组织结构的影响。方法将18只实验犬随机分为3组，深低温停循环（deep hypothermic circulatory arrest，DHCA组）组，深低温停循环结合逆行脑灌注（retrograde cerebral perfusion，RCP，DHCA＋RCP组）组，深低温停循环结合顺行性间断脑灌注（intermittent antegrade cerebral perfusion，IACP，DHCA＋IACP组）组。3组犬体外循环开始后将鼻咽温降至18℃，随后停循环90min，开放循环后复温至36℃，随后停机。在停循环前、停循环后45min、90min及开放循环后15min和30min由颈静脉插管留取血液标本进行S-100蛋白含量测定。手术结束时取脑海马组织作透射电子显微镜检查，观察脑组织及神经细胞超微结构的变化。结果3组犬在停循环前颈静脉血S-100蛋白含量差异无统计学意义（P〉0．05），停循环后DHCA组和DHCA＋RCP组S-100蛋白含量较停循环前显著升高（P〈0．01），DHCA＋IACP组S-100蛋白含量停循环前后无显著变化。结论DHCA时间较长时，脑组织会发生缺血缺氧性损伤；RCP对脑组织有一定的保护作用，但易发生脑组织及神经细胞水肿；IACP的脑保护效果较为理想。

The Influence of Various Methods of Cerebral Protection during Deep Hypothermic Circulatory Arrest on Expression of S-100 Protein

Objective To observe the influence of various methods of cerebral protection during deep hypothermic circulatory arrest （DHCA） on S-100 protein. Methods Eighteen dogs were randomly and equally divided into three groups： the deep hypothermic circulatory arrest （DHCA group）, the DHCA with retrograde cerebral perfusion （DHCA ＋ RCP group）, and the DHCA with intermittent antegrade cerebral perfusion （DHCA ＋ IACP group）. Upon interruption of cardiopulmonary bypass （CPB）, the nasopharyngeal temperature was slowly lowered to 18℃, before CPB was discontinued for 90 minutes, after 90 minutes, CPB was re-established and the body temperature was gradually restored to 36 ℃, then CPB was terminated. Before the circulatory arrest, 45min, 90min after the circulatory arrest and 15min,30min after re-established of CPB, blood samples were drawn from the jugular veins for assay of S -100 protein. Upon completion of surgery, the dogs was sacrificed and the hippocampus was removed from the brain, properly processed for examination by transmission electron microscope for changes in the ultrastructure of the brain and nerve cells. Results There was no significant difference in the content of S-100 protein before circulatory arrest among all three groups （P〉0.05）. After circulatory arrest, DHCA and DHCA＋ RCP group showed an significant increase in the content of S-100 protein（P〈0. 01）. There was no significant difference in the content of S-100 protein after circulatory arrest in DHCA＋IACP group. Conclusion Cerebral ischemic injuries would occur if the period of DHCA is prolonged. RCP during DHCA would provide protection for the brain to some extent, but it is more likely to cause dropsy in the brain and nerve cells. On the other hand IACP during DHCA appears to provide better brain protection.