BMC Cardiovasc Disord. 2013 Jul 28;13:53. doi: 10.1186/1471-2261-13-53.
Ectonucleotidase plays an important role in the regulation of cardiac function by controlling extracellular levels of adenine nucleotides and adenosine. To determine the influence of ischemia-reperfusion injury on ectonucleotidase activity in coronary vascular bed, we compared the metabolic profile of adenine nucleotides during the coronary circulation in pre- and post-ischemic heart.
Langendorff-perfused rat hearts were used to assess the intracoronary metabolism of adenine nucleotides. The effects of ischemia on the adenine nucleotide metabolism were examined after 30 min of ischemia and 30 min of reperfusion. Adenine nucleotide metabolites were measured by high performance liquid chromatography.
ATP, ADP and AMP were rapidly metabolized to adenosine and inosine during the coronary circulation. After ischemia, ectonucleotidase activity of the coronary vascular bed was significantly decreased. In addition, the perfusate from the ischemic heart contained a considerable amount of enzymes degrading ATP, AMP and adenosine. Immunoblot analysis revealed that the perfusate from the ischemic heart dominantly contained ectonucleoside triphosphate diphosphohydrolase 1, and, to a lesser extent, ecto-5'-nucleotidase. The leakage of nucleotide metabolizing enzymes from the coronary vascular bed by ischemia-reperfusion was more remarkable in aged rats, in which post-ischemic cardiac dysfunction was more serious.
Ectonucleotidases were liberated from the coronary vascular bed by ischemia-reperfusion, resulting in an overall decrease in ectonucleotidase activity in the post-ischemic coronary vascular bed. These results suggest that decreased ectonucleotidase activity by ischemia may exacerbate subsequent reperfusion injury, and that levels of circulating ectonucleotidase may reflect the severity of ischemic vascular injury.
核苷酸酶在调节心脏功能方面起着重要作用，可控制细胞外腺嘌呤核苷酸和腺苷的水平。为了确定缺血再灌注损伤对冠状血管床中核苷酸酶活性的影响，我们比较了缺血前后心脏冠状动脉循环中腺嘌呤核苷酸的代谢谱。
使用 Langendorff 灌流的大鼠心脏来评估腺嘌呤核苷酸的冠状动脉内代谢。在缺血 30 分钟和再灌注 30 分钟后，检查了缺血对腺嘌呤核苷酸代谢的影响。通过高效液相色谱法测量腺嘌呤核苷酸代谢物。
在冠状动脉循环中，ATP、ADP 和 AMP 迅速代谢为腺苷和肌苷。缺血后，冠状血管床的核苷酸酶活性显著降低。此外，缺血心脏的灌流液中含有大量降解 ATP、AMP 和腺苷的酶。免疫印迹分析显示，缺血心脏的灌流液主要含有核苷酸三磷酸二磷酸水解酶 1，其次是外切 5'-核苷酸酶。缺血再灌注引起的冠状血管床中核苷酸代谢酶的渗漏在老年大鼠中更为明显，其中缺血后心脏功能障碍更为严重。
缺血再灌注导致冠状血管床中核苷酸酶的释放，导致缺血后冠状血管床中核苷酸酶活性整体降低。这些结果表明，缺血引起的核苷酸酶活性降低可能加重随后的再灌注损伤，而循环中核苷酸酶的水平可能反映缺血性血管损伤的严重程度。
