Yang X, Zhu Q, Layne J R, Claydon M, Hicks G L, Wang T
Department of Surgery, University of Rochester, New York 14642.
Cryobiology. 1993 Aug;30(4):366-75. doi: 10.1006/cryo.1993.1036.
We employed hyperosmotic concentrations of penetrating cryoprotective agents (CPA) to store the isolated rat hearts unfrozen at subzero temperatures. The effect of acute exposure to CPA was assessed by flushing the hearts with CP-14, a cardioplegic solution, containing methanol (MeOH), ethanol (EtOH), ethylene glycol (EG), or propylene glycol (PG) for 2 min and reperfusing immediately with Krebs-Henseleit buffer in a working-heart model. The maximal doses that did not cause irreversible suppression of heart function were: MeOH, 1.78 M; EtOH, 1.27 M; EG, 0.84 M; and PG, 0.87 M. For nonfreezing storage, the hearts were flushed with CP-14 containing the highest tolerable concentrations of MeOH, EtOH, EG, or PG, stored for 6 h at -3.7, -2.8, and -1.4 degrees C, respectively, and then reperfused. Control cardiac output (CO) was 76.2 +/- 1.8 ml/min. Post-reperfusional recovery of CO was 86% in MeOH hearts, 82% in EtOH hearts, 76% in EG hearts, and 79% in PG hearts. Thus MeOH offered not only the least cardiac-suppressing effect but the lowest nonfreezing storage temperature. When storage time was extended, recovery and myocardial ATP level decreased with time in hearts flushed with CP-14 + 1.78 M MeOH and stored at -3.7 degrees C. The decay of function was faster than the decay of ATP level, suggesting energy was better preserved than function. The low return of function, however, may be related to CPA toxicity, osmotic stress, and ischemia/reperfusion injury. Nonfreezing storage at subzero temperatures using these CPAs may provide a novel approach to long-term cardiac preservation.
我们采用高渗浓度的渗透性低温保护剂（CPA）在零下温度下非冷冻保存离体大鼠心脏。通过在工作心脏模型中用含有甲醇（MeOH）、乙醇（EtOH）、乙二醇（EG）或丙二醇（PG）的心脏停搏液CP - 14冲洗心脏2分钟，然后立即用克雷布斯 - 亨泽莱特缓冲液再灌注，来评估急性暴露于CPA的影响。不引起心脏功能不可逆抑制的最大剂量分别为：MeOH，1.78 M；EtOH，1.27 M；EG，0.84 M；PG，0.87 M。对于非冷冻保存，心脏用含有MeOH、EtOH、EG或PG最高耐受浓度的CP - 14冲洗，分别在-3.7、-2.8和-1.4℃下保存6小时，然后再灌注。对照心输出量（CO）为76.2±1.8 ml/分钟。再灌注后，MeOH组心脏的CO恢复率为86%，EtOH组为82%，EG组为76%，PG组为79%。因此，MeOH不仅对心脏的抑制作用最小，而且非冷冻保存温度最低。当延长保存时间时，用CP - 14 + 1.78 M MeOH冲洗并在-3.7℃下保存的心脏，其恢复率和心肌ATP水平随时间下降。功能衰退比ATP水平衰退更快，这表明能量比功能保存得更好。然而，功能恢复率低可能与CPA毒性、渗透压应激和缺血/再灌注损伤有关。使用这些CPA在零下温度下进行非冷冻保存可能为长期心脏保存提供一种新方法。
