Mouse Coronary Angiograph Using Synchrotron Radiation Microangiography
Genetically engineered mice provide enormous potential to study the pathogenesis and treatment of atherosclerosis. However, most experimental designs to investigate mouse coronary atherosclerosis are limited to in vitro and ex vivo examinations. Technological advances in microangiography have facilitated the detailed study of microvessels ex vivo and in vivo; the development of synchrotron radiation (SR) microangiography has enabled us to study mouse coronary arteries in moving hearts. For high-resolution, real-time imaging (10×5 mm, 30 frames/second), a monochromatized x-ray obtained from the third generation SR facility (SPring-8, Japan) and a new x-ray SATICON camera (Hamamatsu Photonics) were used. Digital microangiography with 7-μm pixel sizes was performed.
First, we performed mouse coronary angiography using ex vivo working hearts under the Langendorff perfusion technique and detected coronary atherosclerotic lesions in 5-month-old, cholesterol-fed, apolipoprotein E knockout mice. We also performed in vivo mouse coronary angiography. C57BL/6 mice (25 to 28 g) were anesthetized with pentobarbital, and a SP-8 polyethylene tube (0.5 mm in diameter, Natsume Manufactory) was introduced into the aortic valve through the right carotid artery to infuse iodine contrast agents. As shown in the Figure and the accompanying cine images (can be found Online at http://www.circulationaha.org), use of this system provided us with serial examinations of coronary arteries in situ in genetically engineered mice. Consequently, this system is a powerful tool to study the pathophysiology of coronary artery disease.
Movie versions of the Figure can be found in a Data Supplement at http://www.circulationaha.org