High organoprotective properties of a carbon monoxide (CO)–oxygen (O 2 ) gas mixture were confirmed after prolonged (24-h) preservation of the papillary muscle and an isolated rat heart at 4°C. Hypothermic preservation in the high-pressure gas mixture (6 atm) provided efficient restoration of the contractile activity of the isolated rat heart after 24-h storage at 4°C. The isolated retrograde-perfused Langendorff heart performed physically relevant mechanical work, which was similar in duration to that of an intact control heart. Staining with triphenyltetrazolium chloride did not detect infarcted regions in the myocardium. After preservation, the heart tissue was highly capable of performing its function in a test for electrically stimulated contractile activity of papillary muscles. In the test group, The frequency–intensity relationship, the potentiation effect induced by a pause, and the response to stimulation with isoproterenol of test hearts generally corresponded to the parameters of a normal rat myocardium. A sheep heart, which is comparable in size and weight to a human heart, was for the first time successfully preserved using the gas mixture. Normal heartbeat was spontaneously restored after the start of perfusion in all experiments. Histology did not detect a significant difference between test and control sheep hearts. The normal tissue structure of the myocardium was preserved in the test hearts. The 24-h preservation achieved in the study was four times longer than the maximum allowable preservation time of standard static cold storage. The results obtained with the large laboratory animal heart model showed that the hypothermic preservation protocol is promising for prolonged storage of human hearts.

中文翻译：

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在加压一氧化碳-氧气混合物中长时间低温保存24小时后大鼠心肌和离体羊心脏的状况

在 4°C 下长时间（24 小时）保存乳头肌和离体的大鼠心脏后，证实了一氧化碳 (CO)-氧气 (O 2 ) 气体混合物的高器官保护特性。在 4°C 下储存 24 小时后，在高压气体混合物 (6 atm) 中低温保存可有效恢复离体大鼠心脏的收缩活性。孤立的逆行灌注 Langendorff 心脏执行物理相关的机械工作，其持续时间与完整对照心脏的持续时间相似。用三苯基四唑氯化物染色未检测到心肌中的梗塞区域。保存后，心脏组织在电刺激乳头肌收缩活动的测试中非常有能力发挥其功能。在测试组中，频率-强度关系，由暂停引起的增强效应和对受试心脏的异丙肾上腺素刺激的反应通常与正常大鼠心肌的参数相对应。在大小和重量上与人心脏相当的绵羊心脏首次使用这种气体混合物成功保存。所有实验开始灌注后，心跳均自发恢复。组织学未检测到测试和对照羊心脏之间的显着差异。心肌的正常组织结构保留在测试心脏中。研究中实现的 24 小时保存时间是标准静态冷库最大允许保存时间的四倍。