Analysis of Blood Flow Dynamics in Cerebral Microvessels by a fiber-Optic Laser-Doppler Anemometer Microscope

光纤激光多普勒风速计显微镜分析脑微血管血流动力学

• 批准号: 08671627
• 负责人: SEKI Junji
• 金额: $ 1.41万
• 依托单位: National Cardiovascular Center Research Institute
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08671627/
• 关键词: Brain Pial Microvessels; Laser-Doppler Anemometer; Amplitude of Pulsation; Intravascular Pressure; Nitric Oxide; Wall Shear Stress; Vessel Wall Elasticity; Intracranial Pressure; Transmural Pressure; モデル解析

This research projecto was aimed to analyze the blood flow dynamics undr the various pathological conditions using our developed fiber-optic laser-Doppler anemometer microscope (FLDAM). In particular, effects of incresed intracranial pressure on the pulse wave propagation along the pial arteriolar network and effects of nitric oxide on the velocity distributions in the pial microvessels were studied.To observe the brain pial microcirculation, a closed cranial window was created on the parietal region of the rats. The red cell velocity in single pial microvessels was measured by the FLDAM.The internal pressure of the window, which is equal to the intracranial pressure, was changed between 0 and 50 mmHg. The red cell velocity in arterioles showed regular pulsatile waveforms synchronous with the systemic arterial pressure measured in the femoral artery. The amplitude of velocity pulsation was defined as the half of the difference between the maximum and minimum of the ensemble average vel … More ocity using the systemic pressure as a timing signal. The amplitude of velocity pulsation in the pial arterioles was 24 (]SY.+-。[) 9%, 29 (]SY.+-。[) 9% and 40 (]SY.+-。[) 11% at ICP = 5,30 and 50 mmHg, respectively. It increased gradually with ICP on the average. In individual arterioles, however, the amplitude of velocity pulsation showed a sharp increase at a certain critical value of ICP.The critical ICP ranged between 25 and 40 mmHg, increased with increasing vessel diameter and decreased from upstream to downstream along arteriolar trees. Theoretical calculations wereconducted based on a model assuming that the elastic modulus of arteriolar wall is a step function of transmural pressure and the network architecture is approximated by a porous tapered elastic tube. They suggest that the critical ICP corresponds to the internal pressure of the arteriole.Constant shear stress hypothesis has been introduced to explain the cubic dependence of the volumetric flow in arterioles on vessel diameter. The mechanism of the hypothesis is based on the flow dependent vasodilation mediated by nitric oxide (NO). However, our measurements by the FLDAM revealed that the flow rate in the rat pial arterioles is proportional to the 3.46 (]SY.+-。[) 0.18<@D2-@>D2th power of the diameter, which is significantly different from 3. To investigate the effects of NO on the velocity distribution, the red cell velocity was measured in the pial arterioles with diameter between 20 and 60 mum under the infusion of sodium nitoprusside (SNP,a potent NO donor). Both diamete and mean velocity increased by 14% on the average. The distributions of mean velocity and wall shear rate did not show significant changes compared to the control condition. Less

该研究项目的目的是使用我们开发的光纤激光多普勒（FLDAM）分析各种病理条件的血流动力学。特别是，令人难以置信的颅内压对沿着伴侣小动脉网络脉冲波传播的影响以及一氧化氮对pial微血管速度分布的影响。要观察大脑pial微循环，在大鼠壁区域产生了一个封闭的颅窗。单个PIE微血管中的红细胞速度通过FLDAM测量。窗户的内部压力等于颅内压，在0到50 mmHg之间更改。小动脉中的红细胞速度显示出常规的脉冲波形与股动脉中的全身动脉压同步。速度脉动的幅度定义为集合平均vel的最大值和最小值之间的一半……更多的城市使用全身压力作为定时信号。等级小动物中速度脉动的放大器为24（]SY。+ - 。[）9％，29（]SY。+ - 。[）9％和40（]SY。+ - 。[ICP = 5,30和50 mmHg的11％。随着ICP的平均值，它逐渐增加。然而，在单个小动脉中，速度搏动的放大器在ICP的一定临界值下显示出急剧增加。临界ICP在25至40 mmHg之间，随着血管直径的增加而增加，并且从上游到下游沿着小动脉树的下游降低。理论计算是基于模型进行的，假设小动脉壁的弹性模量是透明压力的步骤函数，并且网络结构由多孔锥形弹性管近似。他们认为临界ICP对应于小动脉的内部压力。已经引入了固定剪切应力假设，以解释小动脉直径对小动脉中的体积流量的立方依赖性。该假设的机制基于一氧化氮（NO）介导的流量依赖性血管舒张。但是，我们对FLDAM进行的测量表明，大鼠幼丘动脉中的流速与3.46（] Sy.+ - 。[）0.18 <@d2-@> d2-@> d2-d2th幂与3的效果与速度分布之间的影响相比，直径为3。氮钠钠（SNP，潜在的无供体）。直径和平均速度的平均值增加了14％。与对照条件相比，平均速度和壁剪率的分布没有显示出显着变化。较少的

项目成果

Seki, J., Sasaki, Y., Oyama, T., Yamamoto, J.: "Blood Flow Pulsation in the Brain Pial Microvessels in Rats Measured by Fiber-Optic LDA Microscope" Laser Anemometry - Advances and Applications. GALA e.V., Karlsruhe. 645-651 (1997)

Seki, J.、Sasaki, Y.、Oyama, T.、Yamamoto, J.：“通过光纤 LDA 显微镜测量大鼠脑软膜微血管中的血流脉动”激光风速测量 - 进展和应用。

Sasaki, Y., Seki, J., Giddings, J.C., and Yamamoto, J.: "Effects of NO-Donors on Thrombus Formation and Microcirculation in Cerebral Vesseil of the Rat" Thrombosis and Haemostasis. 76 (1). 111-117 (1996)

Sasaki, Y.、Seki, J.、Giddings, J.C. 和 Yamamoto, J.：“NO 供体对大鼠脑血管中血栓形成和微循环的影响”血栓形成和止血。

Seki,J.,Sasaki,Y.,Oyama,T.& Yamamoto,J.: "Fiber-Optic Laser-Doppler Anemometer Microscope Applied to the Cerebral Microcirculation in Rats" Biorheology. 33. 463-470 (1996)

关 J.、佐佐木 Y.、小山 T.

Yamamoto, J., Seki, J., et al.: "The Differential Involvement of von Willebrand Factor,Fibrinogen,and Fibronectin in Acute Experimental Thrombosis in Rat Cerebral and Mesenteric Microvessels." Jpn.J.Physiol.47(5). 431-441 (1997)

Yamamoto, J.、Seki, J. 等人：“血管性血友病因子、纤维蛋白原和纤连蛋白在大鼠脑和肠系膜微血管急性实验性血栓形成中的差异参与”。

Sasaki,Y.Taka,T.Yamamoto,J.,Seki,J.: "Nitric Oxide Affects Microcirculation and Thrombus Formation in Rat Pial Vessels" Microcirculation Annual 1996. 12. 113-114 (1996)

Sasaki,Y.Taka,T.Yamamoto,J.,Seki,J.：“一氧化氮影响大鼠软膜血管的微循环和血栓形成”微循环年鉴 1996. 12. 113-114 (1996)