Zaitseva Tatiana, Schears Gregory, Schultz Steven, Creed Jennifer, Antoni Diego, Wilson David F, Pastuszko Anna
Department of Biochemistry and Biophysics, School of Medicine, The University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Ann Thorac Surg. 2005 Jul;80(1):245-50. doi: 10.1016/j.athoracsur.2005.02.016.
The purpose of this study was to determine the effects of low-flow cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest followed by postbypass recovery on the phosphorylation state of transcription factor, cyclic adenosine 3', 5'-monophosphate response element-binding protein (CREB), in the striatum of neonatal brain.
Neonatal piglets (1.4 to 2.5 kg) anesthetized with isoflurane and fentanyl were put on CPB. The animals were cooled to 18 degrees C during a 20-minute period. The CPB circuit flow was then either reduced to 20 mL.kg(-1).min(-1) for 90 minutes (low-flow CPB) or turned off for 90 minutes (deep hypothermic circulatory arrest), following with a gradual increase in the flow and rewarming during a 30-minute period and a 2-hour recovery. At the end of the recovery period, the animals were rapidly euthanized, and the striata were removed and frozen for immunochemical analysis by Western blot technique using antibodies against phosphorylated and total CREB. The results are presented as mean +/- standard deviation (p < 0.05 was significant).
Deep hypothermic circulatory arrest did not result in alteration in either the level of CREB or its degree of phosphorylation in the piglet striatum whereas after low-flow CPB, CREB phosphorylation was significantly increased (p < 0.005) and there was also an increase in CREB expression (p < 0.01).
This study indicates that at 2 hours of recovery, low-flow CPB but not deep hypothermic circulatory arrest causes an increase in CREB phosphorylation and expression. Future studies will determine the degree to which the increase in CREB phosphorylation correlates with cell survival and neuronal injury after CPB.
本研究旨在确定低流量体外循环（CPB）及深低温循环停搏后体外循环恢复对新生仔猪脑纹状体中转录因子环磷腺苷反应元件结合蛋白（CREB）磷酸化状态的影响。
用异氟烷和芬太尼麻醉的新生仔猪（体重1.4至2.5千克）接受CPB。在20分钟内将动物体温降至18摄氏度。然后将CPB回路流量降至20 mL·kg⁻¹·min⁻¹持续90分钟（低流量CPB）或关闭90分钟（深低温循环停搏），随后在30分钟内逐渐增加流量并复温，再恢复2小时。在恢复期末，迅速对动物实施安乐死，取出纹状体并冷冻，采用针对磷酸化和总CREB的抗体，通过蛋白质免疫印迹技术进行免疫化学分析。结果以平均值±标准差表示（p < 0.05为有显著性差异）。
深低温循环停搏未导致仔猪纹状体中CREB水平及其磷酸化程度发生改变，而低流量CPB后，CREB磷酸化显著增加（p < 0.005），CREB表达也增加（p < 0.01）。
本研究表明，在恢复2小时时，低流量CPB而非深低温循环停搏会导致CREB磷酸化和表达增加。未来的研究将确定CPB后CREB磷酸化增加与细胞存活及神经元损伤的相关程度。
