Department of Biophysics Program, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.
Brain Res. 2013 Nov 6;1537:350-5. doi: 10.1016/j.brainres.2013.09.023. Epub 2013 Sep 25.
Crossed cerebellar diaschisis (CCD) caused by contralateral supratentorial lesions can be considered a condition of neural deactivation, and hemodynamic changes in CCD were investigated with positron emission tomography (PET) in humans. In the present study, to investigate the effects of neural deactivation on hemodynamics, we developed a new mouse model of CCD, which was caused by middle cerebral artery occlusion (MCAO), and measured changes in cerebellar blood flow (CbBF), red blood cell (RBC) velocity and concentration due to CCD using laser-Doppler flowmetry (LDF) in awake mice. The ratio of the CCD side to the unaffected side in the cerebellum for CbBF 1 day after MCAO was decreased by -18% compared to baseline (before CCD). The ratio of the CCD side to the unaffected side for RBC concentration 1 day after MCAO was decreased by -23% compared to baseline. However, no significant changes in the ratio of the CCD side to the unaffected side were observed for RBC velocity. The present results indicate that the reduction of CbBF induced by neural deactivation was mainly caused by the decrease in RBC concentration. In contrast, our previous study showed that RBC velocity had a dominant role in the increase in cerebral blood flow (CBF) induced by neural activation. If RBC concentration can be considered an indicator of cerebral blood volume (CBV), hemodynamic changes due to neural activation and deactivation measured by LDF in mice might be in good agreement with human PET studies.
交叉性小脑失联络（CCD）是由对侧幕上病变引起的，可以被认为是一种神经失活状态，人类使用正电子发射断层扫描（PET）研究了 CCD 的血液动力学变化。在本研究中，为了研究神经失活对血液动力学的影响，我们开发了一种新的 MCAO 诱导的 CCD 小鼠模型，并使用激光多普勒血流仪（LDF）在清醒小鼠中测量 CCD 引起的小脑血流（CbBF）、红细胞（RBC）速度和浓度的变化。MCAO 后 1 天，小脑 CCD 侧与未受影响侧的 CbBF 比值与基线（CCD 前）相比降低了-18%。MCAO 后 1 天，小脑 CCD 侧与未受影响侧的 RBC 浓度比值与基线相比降低了-23%。然而，RBC 速度的 CCD 侧与未受影响侧的比值没有明显变化。这些结果表明，神经失活引起的 CbBF 减少主要是由于 RBC 浓度的降低。相比之下，我们之前的研究表明，在神经激活引起的大脑血液流量（CBF）增加中，RBC 速度起着主导作用。如果 RBC 浓度可以被认为是脑血容量（CBV）的指标，那么使用 LDF 在小鼠中测量的神经激活和失活引起的血液动力学变化可能与人的 PET 研究非常吻合。
