Department of Neurology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
Brain Res. 2010 Mar 12;1320:69-73. doi: 10.1016/j.brainres.2010.01.032. Epub 2010 Jan 18.
Employing high-speed camera laser-scanning confocal microscopy with RBC-tracking software, we previously showed that RBC velocities in intraparenchymal capillaries of rat cerebral cortex are distributed over a wide range. In the present work, we measured RBC velocities in mice, whose body weights are less than one-tenth of that of rats. In an isoflurane-anesthetized mouse, a cranial window was opened in the left temporo-parietal region. Intravenously administered FITC-labeled RBCs were automatically recognized and tracked frame-by-frame at 500fps, and the velocities of all RBCs recognized were calculated with our Matlab-domain software, KEIO-IS2. Among 15241 RBCs detected in the ROI in 21 mice, 1655 were identified as flowing in capillaries. The velocities of these RBCs ranged from 0.15 to 8.6mm/s, with a mean of 2.03+/-1.42mm/s. A frequency distribution plot showed that RBC velocities were clustered at around 1.0mm/s, tailing up to 8.6mm/s, and 59% of the RBCs in capillaries showed velocities within the range of 0.5 to 2.0mm/s. Unexpectedly, these characteristics of RBC velocities in mice were very similar to those of rats, despite differences in RBC diameter (6.0 vs. 6.5microm), body size (25 vs. 327g), heart rate (461 vs. 319bpm) and arterial blood pressure (86 vs. 84mmHg). We speculate that physical factors relating to oxygen exchange may constrain general RBC velocity in capillaries to a certain range for optimum oxygen exchange, regardless of species.
利用高速相机激光共聚焦显微镜和 RBC 跟踪软件，我们之前曾表明，大鼠大脑皮质脑实质内毛细血管中的 RBC 速度分布范围很广。在本工作中，我们测量了体重不到大鼠十分之一的小鼠的 RBC 速度。在异氟烷麻醉的小鼠中，在左颞顶区域开颅窗。静脉注射 FITC 标记的 RBC 后，使用我们的 Matlab 域软件 KEIO-IS2 自动逐帧识别和跟踪，计算所有识别出的 RBC 速度。在 21 只小鼠的 ROI 中检测到的 15241 个 RBC 中，有 1655 个被鉴定为在毛细血管中流动。这些 RBC 的速度范围从 0.15 到 8.6mm/s，平均为 2.03+/-1.42mm/s。频率分布图显示，RBC 速度聚集在 1.0mm/s 左右，一直延伸到 8.6mm/s，59%的毛细血管中的 RBC 速度在 0.5 到 2.0mm/s 范围内。出乎意料的是，尽管 RBC 直径（6.0 与 6.5μm）、体型（25 与 327g）、心率（461 与 319bpm）和动脉血压（86 与 84mmHg）存在差异，但小鼠 RBC 速度的这些特征与大鼠非常相似。我们推测，与氧气交换有关的物理因素可能会将一般毛细血管中的 RBC 速度限制在一定范围内，以达到最佳的氧气交换效果，而与物种无关。
