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Microcirculatory hemodynamic changes in cererbral microvascular occusion

脑微血管堵塞时的微循环血流动力学变化

基本信息

批准号：
07457161
负责人：
NIIMI Hideyuki
金额：
$ 2.62万
依托单位：
National Cardiovascular Reseach Institute (NCVC)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

Cerebral microcirculatory hemodynamic changes were investigated during cerebral microvascular occlusion, based on an intravital microscopic observation of the pial microcirculation in cat and rats. The animals were anesthetized with pentobarbital sodium and mechanical ventilated. After craniotomy, a closed cranial window was prepared. We made a direct observation of the microcirculation on the cerebrocortical surface using a fluorescence videomicroscopic system. FITC-labeled red cells and RITC (Rhodamine-B) labeled dextran were used for visualzing microvessels and blood flow, respectively. As a model of microemboli, latex microsheres (diameter : around 40 mum), which were labeled with FITC,were injected into a common carotid artery. Based on RITC video-image, we measured internal diameter, length and network structure, of pial microvessels. Based on FITC videoimage, we measured red cell velocity, using a dual window technique. By scanning over an area of the cerebrocortical surface, we reconstructed the network structure of microvessels. The present fkuorescence videoimage showed that i) cerebrocortical microvessels (arterioles and venules) show an acrcading structure with arteriole-arteriole anastomoses ; ii) the arteriolar arcade proivides a multiple pathway for blood flow. Since the arteriolar arcade was like a rotary to connect main streams, blood flow was never stopped when a single arteriole was occluded with microspheres. Under microvascular occlusion due to microemboli, dypath flow-circuits may work to flow blood continuously in the cerebral microvascular network.

在活体显微镜下观察了猫和大鼠软膜微循环的变化，探讨了脑微血管阻塞时脑微循环血流动力学的变化。用戊巴比妥钠麻醉动物并进行机械通气。开颅手术后，准备一个闭合的颅窗。我们用荧光显微镜系统直接观察了大脑皮层表面的微循环。FITC标记的红细胞和RITC（罗丹明-B）标记的葡聚糖分别用于可视化微血管和血流。作为微栓子的模型，将用FITC标记的乳胶微粒（直径：约40 μ m）注射到颈总动脉中。利用RITC视频图像测量软脑膜微血管的内径、长度和网络结构。在FITC荧光图像的基础上，采用双窗技术测量红细胞运动速度。通过扫描大脑皮层表面的一个区域，我们重建了微血管的网络结构。目前的荧光视频图像显示：i）大脑皮质微血管（小动脉和小静脉）显示出小动脉-小动脉吻合的十字结构; ii）小动脉弓为血流提供了多条路径。由于微动脉拱廊像一个旋转的连接主流，当单个微动脉被微球阻塞时，血流不会停止。在由于微栓子引起的微血管闭塞下，dypath流动回路可以工作以使血液在脑微血管网络中连续流动。