Ye J, Yang L, Del Bigio M R, Filgueiras C L, Ede M, Summers R, Salerno T A, Deslauriers R
Institute for Biodiagnostics, National Research Council of Canada, Winnipeg, Manitoba, Canada.
Ann Thorac Surg. 1996 May;61(5):1316-22. doi: 10.1016/0003-4975(96)00076-8.
Antegrade and retrograde cerebral perfusion during hypothermic circulatory arrest (HCA) has been reported to provide better brain protection during operation than hypothermic circulatory arrest alone. However, the efficacy of these techniques remains to be fully determined, especially when used for prolonged periods. We used a pig model to evaluate the histopathologic consequences of HCA and the potential benefit of cerebral perfusion during HCA.
Twenty-two pigs were divided into four groups and exposed to either anesthesia alone, 120 minutes of HCA (15 degrees C), 120 minutes of retrograde cerebral perfusion at 15 degrees C during HCA, or 120 minutes of antegrade cerebral perfusion at 15 degrees C during HCA, and then reperfused for 60 minutes under cardiopulmonary bypass at 37 degrees C. The brains were perfusion fixed at the end of the experiments and examined by light microscopy.
There were no morphologic changes in any areas of the brains in the anesthesia group, and very minor changes in some areas of the brains in the antegrade cerebral perfusion. group. Varying severity of neuronal damage was found in the brains of all the pigs in the HCA and retrograde cerebral perfusion groups. The severity of ischemic damage in the brain showed the following descending order: hippocampus (CA4), caudate nucleus, cerebral cortex, putamen, thalamus, Purkinje cells of the cerebellum, pons, and mesencephalic gray matter. In the hippocampus the order of damage was CA4, CA3, polymorphous layer of the dentate gyrus, prosubiculum, CA2, CA1, and granule cell layer of the dentate gyrus. The damage in the retrograde cerebral perfusion group was less severe relative to the HCA group in many areas (no significance except mesencephalic gray matter).
These results demonstrate that the pattern of neuronal damage in pigs subjected to HCA and retrograde cerebral perfusion differs from the traditional pattern in that the caudate nucleus and hippocampal CA4 region are the most vulnerable to ischemia-hypoxia. Our results also suggest that antegrade cerebral perfusion prevented ischemic damage to the brain and retrograde cerebral perfusion provided some protection but moderately severe damage occurred.
据报道，在低温循环停搏（HCA）期间进行顺行性和逆行性脑灌注，相比于单纯的低温循环停搏，在手术过程中能提供更好的脑保护。然而，这些技术的疗效仍有待充分确定，尤其是在长时间使用时。我们使用猪模型来评估HCA的组织病理学后果以及HCA期间脑灌注的潜在益处。
22头猪被分为四组，分别接受单纯麻醉、120分钟的HCA（15摄氏度）、HCA期间在15摄氏度下进行120分钟的逆行性脑灌注或HCA期间在15摄氏度下进行120分钟的顺行性脑灌注，然后在37摄氏度的体外循环下再灌注60分钟。实验结束时对大脑进行灌注固定，并通过光学显微镜检查。
麻醉组大脑的任何区域均未出现形态学变化，顺行性脑灌注组大脑的某些区域有非常轻微的变化。在HCA组和逆行性脑灌注组的所有猪的大脑中均发现了不同程度的神经元损伤。脑缺血损伤的严重程度呈以下降序排列：海马体（CA4）、尾状核、大脑皮层、壳核、丘脑、小脑浦肯野细胞、脑桥和中脑灰质。在海马体中，损伤顺序为CA4、CA3、齿状回多形层、前下托、CA2、CA1和齿状回颗粒细胞层。在许多区域，逆行性脑灌注组的损伤相对于HCA组较轻（除中脑灰质外无显著性差异）。
这些结果表明，接受HCA和逆行性脑灌注的猪的神经元损伤模式与传统模式不同，尾状核和海马体CA4区域最易受到缺血缺氧的影响。我们的结果还表明，顺行性脑灌注可预防脑缺血损伤，逆行性脑灌注提供了一定的保护作用，但仍发生了中度严重的损伤。
