Tangelder G J, Slaaf D W, Arts T, Reneman R S
Department of Physiology, University of Limburg, Maastricht, The Netherlands.
Am J Physiol. 1988 Jun;254(6 Pt 2):H1059-64. doi: 10.1152/ajpheart.1988.254.6.H1059.
Velocity profiles, as determined in vivo in rabbit mesenteric arterioles with fluorescently labeled platelets as natural flow markers, were used to calculate least estimates of the actual wall shear rate in these microvessels (17-32 micron diam). The fit of the velocity data points described the profile as close to the wall as 0.5 micron. To satisfy the no-slip condition, a thin layer of fluid with a steep velocity gradient near the wall was assumed. Least estimates of wall shear rate, as calculated from the fitted platelet-velocity profiles and using the mean velocity gradient in this layer of fluid, ranged from 472 to 4,712 s-1 with a median value of 1,700 s-1. Red blood cell center-line velocities varied between 1.3 and 14.4 mm/s (median 3.4). The wall shear rates were at least 1.46-3.94 (median 2.12) times higher than expected on the basis of a parabolic velocity distribution but with the same volume flow in the vessel. Considerable spatial differences in wall shear rate might exist even within a short segment of a vessel.
利用以荧光标记血小板作为自然流动标志物在兔肠系膜小动脉体内测定的速度剖面，来计算这些微血管（直径17 - 32微米）中实际壁面切应力的最小估计值。速度数据点的拟合将靠近壁面至0.5微米处的剖面描述出来。为满足无滑移条件，假定在壁面附近存在一层具有陡峭速度梯度的薄流体层。根据拟合的血小板速度剖面并利用该流体层中的平均速度梯度计算得到的壁面切应力最小估计值范围为472至4712 s⁻¹，中位数为1700 s⁻¹。红细胞中心线速度在1.3至14.4毫米/秒之间变化（中位数为3.4）。壁面切应力比基于抛物线速度分布且血管内体积流量相同情况下预期的至少高1.46 - 3.94倍（中位数为2.12）。即使在血管的一小段内，壁面切应力也可能存在相当大的空间差异。
