Department of Mechanical Engineering, University of Rochester, Rochester, United States.
Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, United States.
Elife. 2021 Mar 9;10:e65958. doi: 10.7554/eLife.65958.
Cerebrospinal fluid (CSF) flowing through periarterial spaces is integral to the brain's mechanism for clearing metabolic waste products. Experiments that track tracer particles injected into the cisterna magna (CM) of mouse brains have shown evidence of pulsatile CSF flow in perivascular spaces surrounding pial arteries, with a bulk flow in the same direction as blood flow. However, the driving mechanism remains elusive. Several studies have suggested that the bulk flow might be an artifact, driven by the injection itself. Here, we address this hypothesis with new in vivo experiments where tracer particles are injected into the CM using a dual-syringe system, with simultaneous injection and withdrawal of equal amounts of fluid. This method produces no net increase in CSF volume and no significant increase in intracranial pressure. Yet, particle-tracking reveals flows that are consistent in all respects with the flows observed in earlier experiments with single-syringe injection.
脑脊液（CSF）在动脉周围空间流动，这是大脑清除代谢废物的机制的重要组成部分。将示踪粒子注入小鼠脑的蛛网膜下腔（CM）的实验表明，在围绕软脑膜动脉的血管周围空间中存在脉动 CSF 流动的证据，其流动方向与血流相同。然而，驱动机制仍然难以捉摸。几项研究表明，这种整体流动可能是一种假象，是由注射本身驱动的。在这里，我们使用双注射器系统将示踪粒子注入 CM，同时等量注入和抽出液体，从而解决了这一假设。这种方法不会导致 CSF 体积的净增加，也不会导致颅内压的显著增加。然而，示踪粒子追踪揭示了与以前使用单注射器注射的实验中观察到的流动在所有方面都一致的流动。
