Schunke Kathryn J, Toung Thomas K, Zhang Jian, Pathak Arvind P, Xu Jiadi, Zhang Jiangyang, Koehler Raymond C, Faraday Nauder
Department of Anesthesiology/Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
J Neurosci Methods. 2015 Jan 15;239:65-74. doi: 10.1016/j.jneumeth.2014.10.001. Epub 2014 Oct 12.
Most ischemic strokes in humans are caused by ruptured arterial atheroma, which activate platelets and produce thrombi that occlude cerebral vessels.
To simulate these events, we threaded a catheter through the internal carotid artery toward the middle cerebral artery (MCA) orifice and injected collagen directly into the cerebral circulation of male C57Bl/6 mice and Wistar rats.
Laser-Doppler flowmetry demonstrated reductions in cerebral blood flow (CBF) of ∼80% in mice and ∼60% in rats. CBF spontaneously increased but remained depressed after catheter withdrawal. Magnetic resonance imaging showed that ipsilateral CBF was reduced at 3h after collagen injection and markedly improved at 48 h. Micro-computed tomography revealed reduced blood vessel density in the ipsilateral MCA territory at 3 h. Gross examination of excised brains revealed thrombi within ipsilateral cerebral arteries at 3 h, but not 24 h, after collagen injection. Immunofluorescence microscopy confirmed that platelets and fibrinogen/fibrin were major components of these thrombi at both macrovascular and microvascular levels. Cerebral infarcts comprising ∼30% of hemispheric volume and neurobehavioral deficits were observed 48 h after ischemic injury in both mice and rats.
Collagen injection caused brain injury that was similar in magnitude and variability to mechanical MCA occlusion or injection of a pre-formed clot; however, alterations in CBF and the mechanism of vascular occlusion were more consistent with clinical ischemic stroke.
This novel rodent model of ischemic stroke has pathophysiologic characteristics consistent with clinical atherothrombotic stroke, is technically feasible, and creates reproducible brain injury.
人类大多数缺血性中风是由破裂的动脉粥样硬化斑块引起的，这些斑块会激活血小板并形成血栓，从而阻塞脑血管。
为了模拟这些事件，我们将一根导管经颈内动脉穿向大脑中动脉（MCA）开口处，并将胶原蛋白直接注入雄性C57Bl/6小鼠和Wistar大鼠的脑循环中。
激光多普勒血流仪显示，小鼠脑血流量（CBF）降低约80%，大鼠降低约60%。CBF在导管撤出后虽有自发增加，但仍处于较低水平。磁共振成像显示，注射胶原蛋白后3小时同侧CBF降低，48小时时明显改善。微型计算机断层扫描显示，注射后3小时同侧MCA区域血管密度降低。对切除大脑的大体检查显示，注射胶原蛋白后3小时同侧脑动脉内有血栓，但24小时时没有。免疫荧光显微镜检查证实，在大血管和微血管水平，血小板和纤维蛋白原/纤维蛋白都是这些血栓的主要成分。在小鼠和大鼠缺血损伤48小时后，观察到脑梗死占半球体积的约30%，并出现神经行为缺陷。
胶原蛋白注射导致的脑损伤在程度和变异性上与机械性MCA闭塞或注射预先形成的血栓相似；然而，CBF的变化和血管闭塞机制与临床缺血性中风更为一致。
这种新型的啮齿动物缺血性中风模型具有与临床动脉粥样硬化血栓形成性中风一致的病理生理特征，技术上可行，且能造成可重复的脑损伤。
