FLUORESCENCE VITAL-MICROSCOPIC STUDY FOR CAPILLARY PERMEABILITY OF MACROMOLECULES

扩散和对流可能被认为是骨骼肌中大分子跨毛细血管交换的主要驱动力。为了确定这些渗透性参数沿着一个单一的毛细管，我们新开发了一种荧光生命显微镜，其中一对定义良好的狭缝光束（28 μ m的宽度）被集中在一个选定的深度的组织区域，包括只有一个毛细管交叉。光束激发荧光示踪剂（FITC-葡聚糖，M.W.= 40，000、70，000和150，000）集中在由显微镜物镜的焦平面调节的交叉平面上。该显微镜用于独立地量化大分子跨毛细血管运动的扩散（P）和对流（V）分量。通过将该方法应用于血管舒张下的兔细肌，证实了对流在毛细血管的所有区域的大分子的跨毛细血管交换中占主导地位的扩散。此外，在这项研究中获得的P值表明，在微静脉端的毛细血管壁有大约40倍以上的亲和力，通过大分子比在真正的毛细血管。

Diffusion and convection may be considered to be the main driving forces for the transcapillary exchange of macromolecules in the skeletal muscle. To determine these permeability parameters along a single capillary, we have newly developed a fluorescence vital-microscope, in which a pair of well-defined slit beams (28mum in width) were focused to cross at a chosen depth of the tissue region including only a single capillary. The beams excite the fluorescent tracer (FITC-Dextran, M.W.=40,000, 70,000 and 150,000) intensively at the crossing plane which is adjusted by the focal plane of the objective of the microscope. This microscope was applied to quantify the diffusive (P) and convective (V) components of the transcapillary movement of macromolecules independently. By applying this method to rabbit tenuissimus muscle under vasodilation, it was confirmed that convection is dominant to diffusion in the transcapillary exchange of macromolecules at all regions of the capillary. Furthermore, P values obtained in this study suggest that the capillary wall at the venular end has approximately 40 times more affinity to pass macromolecules than that at the true capillary.