Bekker A Y, Ritter A B, Durán W N
Department of Physiology, UMDNJ-New Jersey Medical School, Newark 07103-2757.
Microvasc Res. 1989 Sep;38(2):200-16. doi: 10.1016/0026-2862(89)90028-9.
The dynamics of macromolecular transport across microvascular walls were studied in the hamster cheek pouch by intravital fluorescence microscopy. A graded series of fluorescein isothiocyanate-labeled dextrans (FITC-Dx) of 20,000-70,000 MW was used as macromolecular tracers. The time-dependent extravasation of FITC-Dxs was videotaped for about 2.5 hr to allow for tracer equilibration in the interstitial space. Permeation of macromolecules from individual microvessels was quantified by digital video-image processing. Histograms of the light intensity distributions for selected fields at various times were measured and used to construct integral optical density-time profiles of the extravasated fluorochromes for particular leaky sites. A nonlinear regression algorithm was employed to determine the effective microvascular permeability (P) for the macromolecules studied using a one-dimensional two-compartmental diffusion model and a step change in macromolecular concentration at the boundary. The calculated P's (X 10(-8) cm/sec) were 47.8 +/- 8.7 for FITC-Dx 20; 31.7 +/- 5.9 for FITC-Dx 40, and 17.5 +/- 4.1 for FITC-Dx 70. Our values are comparable to those obtained by whole organ techniques. The observed differences can be explained by explicit consideration of interstitial resistance in the calculations.
通过活体荧光显微镜术研究了仓鼠颊囊微血管壁上大分子转运的动力学。使用一系列分子量为20,000 - 70,000的异硫氰酸荧光素标记葡聚糖（FITC - Dx）作为大分子示踪剂。对FITC - Dx随时间的外渗情况进行了约2.5小时的录像，以使示踪剂在间质空间达到平衡。通过数字视频图像处理对单个微血管中大分子的渗透进行定量。测量了不同时间选定区域光强度分布的直方图，并用于构建特定渗漏部位外渗荧光染料的积分光密度 - 时间曲线。采用非线性回归算法，使用一维双室扩散模型和边界处大分子浓度的阶跃变化来确定所研究大分子的有效微血管通透性（P）。计算得到的FITC - Dx 20的P值（×10⁻⁸ cm/sec）为47.8 ± 8.7；FITC - Dx 40的为31.7 ± 5.9，FITC - Dx 70的为17.5 ± 4.1。我们的值与通过全器官技术获得的值相当。计算中明确考虑间质阻力可以解释观察到的差异。
