Protective effect and mechanism of low P50 haemoglobin oxygen carrier on isolated rat heart

The protection of the isolated heart is very important in heart transplantation surgery, meanwhile, the ischaemia/reperfusion (I/R) of the isolated heart is the main cause of its damage. A timely supply of oxygen can significantly improve the prevention of myocardial ischaemia, however, the cardioprotective solution does not have an oxygen supply function. Haemoglobin Based on Oxygen Carriers (HBOCs) is a kind of nano-oxygen drug, which can effectively and timely supply oxygen to hypoxic organs and tissues. However, the oxygen-carrying and releasing capacity (P50) is different with different HBOCs. The aim of our study was to investigate whether STS (a kind of cardioprotective solution, St Thomas Solution) +different P50 HBOCs provide superior myocardial protection and decrease myocardial injury compared to only STS in rats Langendorff isolated heart perfusion model. The results showed that STS + HBOCs can improve cardiac function at 37 °C for 35 min and 120 min, and reduce myocardial infarctions, pathological changes, and apoptosis of cardiomyocytes, and the STS + low P50 HBOCs is more effective than the other two higher P50 HBOCs. We further demonstrated the outstanding protective effect of STS + low P50 HBOCs on cardiac function, reducing myocardial infarctions and apoptosis of cardiomyocytes in rat Langendorff isolated heart perfusion model.

离体心脏保护在心脏移植手术中具有至关重要的意义，而离体心脏的缺血/再灌注（Ischaemia/Reperfusion, I/R）损伤是导致其功能受损的主要原因。及时供氧可显著改善心肌缺血的防治效果，但现有心脏保护液并不具备供氧功能。血红蛋白基氧载体（Haemoglobin-Based Oxygen Carriers, HBOCs）是一类纳米氧药物，能够高效且及时地向缺氧器官与组织递送氧气。不过，不同的血红蛋白基氧载体的氧结合与释放能力（P50）存在显著差异。本研究旨在探究：在大鼠Langendorff离体心脏灌注模型中，联合使用STS（一种心脏保护液，St Thomas Solution）与不同P50值的HBOCs，对比单纯使用STS，能否实现更优异的心肌保护效果并减轻心肌损伤。实验结果显示，37℃条件下，STS联合HBOCs可在灌注35分钟及120分钟时改善心脏功能，同时减少心肌梗死面积、病理损伤及心肌细胞凋亡；其中，STS联合低P50值HBOCs的保护效果优于另外两种高P50值HBOCs。本研究进一步证实，在大鼠Langendorff离体心脏灌注模型中，STS联合低P50值HBOCs可显著改善心脏功能，减轻心肌梗死与心肌细胞凋亡，展现出优异的心肌保护效能。