title: Imaging of the closed-chest mouse pulmonary circulation using synchrotron radiation microangiography.
abstract: Structural and functional changes of pulmonary circulation related to pathophysiology of pulmonary arterial hypertension (PAH) remain to be fully elucidated. Angiographic visualization in in vivo animals provided a powerful tool for assessing the major indexes associated with the pathogenesis of PAH. In this study, we have exploited the full potential of synchrotron radiation (SR) microangiography to show the ability to visualize pulmonary hemodynamics in a closed-chest mouse. Male adult mice were anesthetized and cannulated with a customized 24-gauge catheter into the right ventricle via the jugular vein for administering iodine contrast agent. The microangiography was performed on the left lung. We measured dynamic changes in vessel diameter in response to acetylcholine (ACh) and acute exposure to hypoxic gas (10% O(2)). Moreover, the pulmonary transit time was estimated by the time of contrast agent circulating. We were able to visualize the pulmonary arteries from the left pulmonary artery (LPA) to the third generation of branching (inner diameter <100 μm). ACh and acute hypoxia induced vascular responses chiefly in the second and third branching vessels rather than the LPA and the first branching vessels. The transit time was only 0.83 s. These results demonstrate the effectiveness of SR for visualizing the pulmonary circulation in a closed-chest mouse. Future studies using SR microangiography on specific gene-targeted knockout and transgenic mice will provide new insights into the pathophysiology of pulmonary dysfunction and functional adaptation to survive in hypoxic condition.
authors.affiliation: Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Sonobe
authors.forename: Daryl O
authors.initials: DO
authors.lastname: Schwenke
authors.forename: James T
authors.initials: JT
authors.lastname: Pearson
authors.forename: Misa
authors.initials: M
authors.lastname: Yoshimoto
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Fujii
authors.forename: Keiji
authors.initials: K
authors.lastname: Umetani
authors.forename: Mikiyasu
authors.initials: M
authors.lastname: Shirai
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000792:Angiography / Q000379:methods*; D000818:Animals; D001783:Blood Flow Velocity; D003287:Contrast Media; D000860:Hypoxia / Q000000981:diagnostic imaging / Q000503:physiopathology; D008168:Lung / Q000098:blood supply*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008833:Microcirculation / Q000187:drug effects; D011651:Pulmonary Artery / Q000000981:diagnostic imaging* / Q000187:drug effects; D011652:Pulmonary Circulation / Q000187:drug effects; D012039:Regional Blood Flow; D017356:Synchrotrons; D013997:Time Factors; D014661:Vasoconstriction; D014664:Vasodilation; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D003287:Contrast Media; D014665:Vasodilator Agents; D000109:Acetylcholine