Carotid artery occlusion and collateral circulation in C57Black/6J mice detected by synchrotron radiation microangiography.

Using monochromatic synchrotron radiation, we performed microangiography in C57BL/6J mice and investigated their vasculature after unilateral and bilateral carotid artery occlusion. Bilateral occlusion of the carotid artery was made by a ligation of the left common carotid artery followed by a ligation of the right internal carotid artery (ICA) two days later (n=12). Five days after the second surgery, angiography was performed. Unilateral occlusion was made by clipping the right ICA and then angiography was performed immediately (n=5). The control mice did not undergo any occlusion (n=5). We removed the brain of the bilateral occlusion mice after angiography and examined the infarction area. The cerebral microvessels in all animals were clearly visualized. In the control mice, the posterior communicating artery (Pcom) was not visualized. In the unilateral occlusion mice, the anastomosis of the pterygopalatine artery (PPA) and the external carotid artery (ECA) were recognized. The PPA is thus considered to play a role in the collateral vessel between the ICA and the ECA. The Pcom was not visualized. In the bilateral occlusion mice, the Pcom was observed either unilaterally (n=5) or bilaterally (n=5). The Pcom supplied blood flow to the anterior circulation from the vertebrobasilar arteries. The bilateral occlusion mice that had at least one visualized Pcom did not have any infarction. We could successfully visualize the cerebral vasculature of normal mice and carotid artery occluded mice in an in vivo study. Microangiography can demonstrate the development of vasculature and the blood flow dynamics in mice.