FLUORESCENCE VITAL-MICROSCOPIC STUDY FOR CAPILLARY PERMEABILITY OF MACROMOLECULES

扩散和对流可以被认为是骨骼肌中大分子经毛细血管交换的主要驱动力。为了确定沿着单个毛细管的这些渗透性参数，我们新开发了一种荧光生命显微镜，其中一对明确定义的狭缝光束（宽度为28mum）被聚焦在仅包括单个毛细管的组织区域的选定深度交叉。光束在显微镜物镜焦平面调节的交叉平面上强烈激发荧光示踪剂（FITC-Dextran， M.W.= 40,70,150000）。应用该显微镜分别量化大分子经毛细血管运动的扩散(P)和对流(V)分量。将该方法应用于血管舒张状态下的兔腱肌，证实了在毛细血管各区域大分子的经毛细血管交换中对流优于扩散。此外，本研究获得的P值表明，静脉端毛细血管壁对大分子的亲和力比真毛细血管壁高约40倍。

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.