Hebden R A, Nathan H J
Division of Cardiac Anaesthesia, University of Ottawa Heart Institute, Ottawa Civic Hospital, Ontario.
Can J Cardiol. 1994 May;10(4):477-83.
To investigate the cardioprotective effect of both the amino terminal of bovine parathyroid hormone (bPTH-[1-34]) and human parathyroid hormone (hPTH-[1-84]) following coronary artery occlusion.
Animals were randomly assigned to one of three treatment groups following circumflex coronary artery occlusion.
Experiments were performed using 19 mongrel dogs of either sex. As four animals died during experimentation, data are shown for 15 dogs (n = 5 for each treatment group).
Animals received saline, bPTH-(1-34) or hPTH-(1-84) following occlusion of the circumflex coronary artery. Peptides were given at 0.008 nmol/kg/min. All treatments were infused directly into the coronary circulation. Infusion rate was 1 mL/min for 10 mins at 30 min intervals until the end of the experiment (480 mins after onset of occlusion). Hemodynamic variables were monitored throughout the experiment. Radioactive microspheres were injected 10 mins before, and 30, 240 and 480 mins following, occlusion of the coronary vessel to determine regional myocardial blood-flows. At the end of the experiment, area at risk and infarct size were measured by simultaneous infusion of Evans blue dye and triphenyl tetrazolium chloride stain.
Neither bPTH-(1-34) nor hPTH-(1-84) significantly reduced area of risk or infarct size as a percentage of area at risk compared with controls. These results were corroborated by regional blood-flows measured using radioactive microspheres. There was no significant difference in hemodynamic variables among the groups except that left atrial pressure was consistently lower following treatment with hPTH-(1-84).
No evidence was found that either bPTH-(1-34) or hPTH-(1-84) salvaged ischemic myocardium in a canine model of myocardial infarction. Treatment with hPTH-(1-84) was associated with a reduction in left atrial pressure. This latter phenomenon may constitute a beneficial effect of this peptide on diastolic myocardial function.
研究牛甲状旁腺激素氨基末端（bPTH-[1-34]）和人甲状旁腺激素（hPTH-[1-84]）在冠状动脉闭塞后的心脏保护作用。
在冠状动脉回旋支闭塞后，将动物随机分为三个治疗组之一。
使用19只雌雄不限的杂种犬进行实验。由于4只动物在实验过程中死亡，因此给出了15只犬的数据（每个治疗组n = 5）。
在冠状动脉回旋支闭塞后，动物接受生理盐水、bPTH-(1-34)或hPTH-(1-84)。肽以0.008 nmol/kg/min的剂量给药。所有治疗均直接注入冠状动脉循环。输注速率为1 mL/min，持续10分钟，每隔30分钟重复一次，直至实验结束（闭塞开始后480分钟）。在整个实验过程中监测血流动力学变量。在冠状动脉闭塞前10分钟以及闭塞后30、240和480分钟注射放射性微球，以确定局部心肌血流量。实验结束时，通过同时注入伊文思蓝染料和氯化三苯基四氮唑染色来测量危险区域面积和梗死面积。
与对照组相比，bPTH-(1-34)和hPTH-(1-84)均未显著降低危险区域面积或梗死面积占危险区域面积的百分比。使用放射性微球测量的局部血流量证实了这些结果。除了用hPTH-(1-84)治疗后左心房压力持续较低外，各组之间的血流动力学变量没有显著差异。
在犬心肌梗死模型中，未发现bPTH-(1-34)或hPTH-(1-84)挽救缺血心肌的证据。hPTH-(1-84)治疗与左心房压力降低有关。后一种现象可能构成该肽对舒张期心肌功能的有益作用。
