Ethier C R, Coloma F M, Sit A J, Johnson M
Department of Mechanical Engineering and Ophthalmology, University of Toronto, Ontario, Canada.
Invest Ophthalmol Vis Sci. 1998 Oct;39(11):2041-8.
It has been reported that fixation conditions significantly influence the apparent pore density in the inner-wall endothelium of Schlemm's canal. In the present study, the manner in which fixation conditions affect the two subtypes of inner-wall pores, intracellular pores and intercellular (or border) pores, was investigated.
Outflow facility was measured in enucleated human eyes. Eyes were fixed under constant flow" or constant pressure conditions, microdissected to expose the inner wall of Schlemm's canal, and prepared for scanning electron microscopy. The density and diameter of the two subtypes of pores in the inner wall were measured.
Intracellular pore density decreased with increasing postmortem time (P < 0.001) and increased with increasing volume of fixative passed through the outflow pathway (P < 0.001), whereas border pore density showed no dependence on these parameters (P > 0.25 and P > 0.15, respectively). Border pore density increased with increasing fixation pressure (P < 0.005), even though intracellular pore density showed no such dependence (P > 0.4). No correlation was found between outflow facility and the predictions of Poiseuille's law, Sampson's law, or the funneling theory for the hydraulic conductivity of the intracellular pores (P > 0.35) or the border pores (P > 0.1).
The intracellular and border pores form two morphologically and functionally distinct populations in the inner wall of Schlemm's canal. The dependence of intracellular pore density on postmortem time and on volume of fixative passed through the outflow pathway suggests that these pores are artifacts of tissue fixation or processing conditions. That border pores do not depend on such conditions and that their presence is correlative with perfusion pressure suggests that this population may be nonartifactual. New histologic techniques for examining the inner wall of Schlemm's canal are necessary to determine the in vivo state of inner-wall pores and how they influence outflow facility.
据报道，固定条件会显著影响施莱姆管内壁内皮细胞的表观孔隙密度。在本研究中，研究了固定条件影响内壁两种孔隙亚型（细胞内孔隙和细胞间（或边界）孔隙）的方式。
在摘除的人眼中测量流出率。眼睛在恒流或恒压条件下固定，进行显微解剖以暴露施莱姆管内壁，并制备用于扫描电子显微镜检查。测量内壁两种孔隙亚型的密度和直径。
细胞内孔隙密度随死后时间增加而降低（P < 0.001），并随通过流出途径的固定剂体积增加而增加（P < 0.001），而边界孔隙密度与这些参数无关（分别为P > 0.25和P > 0.15）。边界孔隙密度随固定压力增加而增加（P < 0.005），尽管细胞内孔隙密度无此依赖性（P > 0.4）。未发现流出率与泊肃叶定律、桑普森定律或细胞内孔隙（P > 0.35）或边界孔隙（P > 0.1）水力传导率的漏斗理论预测之间存在相关性。
细胞内孔隙和边界孔隙在施莱姆管内壁形成两个形态和功能上不同的群体。细胞内孔隙密度对死后时间和通过流出途径的固定剂体积的依赖性表明，这些孔隙是组织固定或处理条件的人为产物。边界孔隙不依赖于此类条件，且其存在与灌注压力相关，这表明该群体可能不是人为的。需要新的组织学技术来检查施莱姆管内壁，以确定内壁孔隙的体内状态及其对流出率的影响。
