Novel Approaches to Study Coronary Vasculature Development in Mice

Background: Coronary artery development is an intensely studied field. Mice are a popular genetic model for developmental studies, but there is no widely accepted protocol for high-throughput, high-resolution imaging of their developmental and adult coronary artery anatomy. Results: Using tissue-clearing protocols and confocal microscopy, we have analyzed embryonic and juvenile mouse hearts in Cx40:GFP knock-in models with a special focus on septal artery development. We found that the septal artery, which supplies the interventricular septum, was initially formed as an arterial plexus that connected to both the left and right coronary arteries. During development, the plexus was remodeled into a single tube, which then remained connected only to the right coronary artery. Since optical imaging became limited at postnatal stages, it was supplemented with injection techniques using India ink and Microfil; the latter was subsequently analyzed with micro-CT to visualize the anatomy of coronary vessels in 3D. Conclusions: The techniques described here enable us to study the finer details of coronary artery development in mice and can, therefore, be implemented to study the pathogenesis of coronary malformations in various mouse models. (C) 2018 Wiley Periodicals, Inc.