Changes in macrovessel pulmonary blood flow distribution following chronic hypoxia: assessed using synchrotron radiation microangiography
Changes in macrovessel pulmonary blood flow distribution following chronic hypoxia: assessed using synchrotron radiation microangiography
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DOI：
10.1152/japplphysiol.00610.2007
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发表时间：
2008-01-01
影响因子：
3.3
通讯作者：
Shirai, Mikiyasu
中科院分区：
文献类型：
--
作者：
Schwenke, Daryl O.;Pearson, James T.;Shirai, Mikiyasu
肺循环的结构和功能变化，特别是在肺动脉高压（PAH）的发病机制，仍有待充分阐明。在这项研究中，我们利用单色同步辐射（SR）微血管造影评估肺小动脉血流的变化，在完整的胸部大鼠慢性缺氧后4周。将Sprague-Dawley大鼠暴露于常氧（N-大鼠）或慢性缺氧（10%O-2; CH-大鼠）28天。麻醉大鼠，在左肺上进行微血管造影术，以评估1）肺小动脉血流（内径>80 μ m）的分支分布和2）在急性低氧（8%O-2，4分钟）肺血管收缩（HPV）期间在阻断β-肾上腺素受体（2 mg/kg，iv心得安）之前和之后血管腔直径的动态变化。使用SR血管造影术，我们观察到CH-大鼠的不透明第三和第四代血管（100-300 μ m）的数量明显少于N-大鼠的数量。CH-大鼠和N-大鼠之间HPV的大小没有差异。β-肾上腺素受体阻断剂加重了CH-大鼠200- 300 μ m血管中的HPV，但在N-大鼠中更是如此。然而，在CH大鼠中，β-肾上腺素受体阻断剂也加重了100- 200 μ m血管中的HPV。总之，我们利用SR来评估总体血流变化和功能变化（即，HPV）的肺循环。这些结果突出了SR用于评估肺循环病理的益处。特别重要的是，SR的未来使用将为评估PAH的潜在治疗提供一种有效的方法。
Structural and functional changes of the pulmonary circulation, particularly during the pathogenesis of pulmonary arterial hypertension (PAH), remain to be fully elucidated. In this study, we utilized monochromatic synchrotron radiation (SR) microangiography to assess changes in pulmonary arteriole blood flow in the intact-chest rat after 4 wk of chronic hypoxia. Sprague-Dawley rats were exposed to normoxia (N-rats) or chronic hypoxia (10% O-2; CH-rats) for 28 days. Rats were anesthetized, and microangiography was performed on the left lung to assess 1) the branching distribution of pulmonary arteriole blood flow (internal diameter >80 mu m) and 2) dynamic changes in vessel lumen diameter during acute hypoxic (8% O-2 for 4 min) pulmonary vasoconstriction (HPV) before and after beta-adrenoceptor blockade (2 mg/kg iv propranolol). Using SR angiography, we observed that the number of opaque third-and fourth-generation vessels (100-300 mu m) for CH-rats was significantly fewer than the number for N-rats. The magnitude of HPV was not different between CH-rats and N-rats. beta-Adrenoceptor blockade accentuated the HPV in 200- to 300-mu m vessels for CH-rats, but even more so in N-rats. However, in CH-rats, beta-adrenoceptor blockade also accentuated the HPV in 100- to 200-mu m vessels. In summary, we utilized SR to assess gross blood flow changes and functional changes (i.e., HPV) of the pulmonary circulation in PAH. These results highlight the benefits of SR for assessing pulmonary circulatory pathology. Of particular importance, future use of SR will provide an effective method for assessing potential therapeutic treatments for PAH.