Effects of paracentesis on the blood-aqueous barrier: an electron microscope study on Macaca mulatta using horseradish peroxidase as a tracer.
Effects of paracentesis on the blood-aqueous barrier: an electron microscope study on Macaca mulatta using horseradish peroxidase as a tracer.
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腹腔穿刺术对血水屏障的影响：使用辣根过氧化物酶作为示踪剂对猕猴进行电子显微镜研究。
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发表时间：
1974
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通讯作者：
G. Raviola
中科院分区：
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作者：
G. Raviola
辣根过氧化物酶（分子量40，000; ac ^- 2.5 nm。0.5 GM.每公斤体重; HRPO）注射到恒河猴（Macacamulatta）的股静脉中，并研究了示踪剂在对照动物和穿刺后眼前段中的扩散。检查眼睛的以下区域：睫状体、虹膜、Schlemm管、下小管结缔组织和小梁网。在对照动物中，从睫状体基质的有孔血管中逃逸的示踪剂渗透到色素细胞之间的细胞间隙以及介于色素细胞和非色素细胞的相对顶点之间的细胞间隙;它最终被连接非色素细胞侧面的紧密连接所阻断。在虹膜中，血管壁对示踪剂是不可渗透的。Schlemm管，小管结缔组织，和。小梁网始终不含HRPO。穿刺后，继发性房水显示HRPO溶液的典型紫色。虹膜的睫状上皮和血管的渗透性是未修改的。Schlemm管的管腔被含示踪剂的血液侵入;通过管内壁的内皮衬里中新形成的间隙，示踪剂迅速扩散到jtixtacanalidar结缔组织、小梁网和前房中。因此提出了这样的观点，即在房水抽出时眼内压的突然下降导致血液从巩膜外静脉回流到Schlemm管，血浆蛋白迅速泄漏到前房中。在本实验的基础上，普遍认为浆状房水的血浆蛋白来源于睫状上皮或虹膜的观点不再被接受。穿刺术对代表血-房水屏障的形态学对应物的连接的渗透性特性没有影响。它打破了水动力学平衡，这种平衡确保了房水从后房到巩膜外静脉的单向流动。
Horseradish peroxidase (MW 40,000; ac ^— 2.5 nm.; 0.5 Gm. per kilogram of body weight; HRPO) ivas injected into the femoral vein of rhesus monkeys (Macaca mulatta) and the diffusion of the tracer was studied in the anterior segment of the eye in control animals and after paracentesis. The following regions of the eye were examined: ciliary body, iris, Schlemm's canal, juxtacanalicular connective tissue, and trabecular meshwork. In the control animals the tracer which escapes from the fenestrated vessels of the ciliary body stroma permeates the intercellular spaces between the pigmented cells and those intervening between the facing apices of the pigmented and nonpigmented cells; it is finally blocked by the tight junctions which connect the lateral surfaces of the nonpigmented cells. In the iris, the vessel wall is impermeable to the tracer. The Schlemm canal, juxtacanalicular connective tissue, and. trabecular meshwork are consistently free of HRPO. Following paracentesis, the secondary aqueous humor displays the typical purple color of HRPO in solution. The permeability properties of both the ciliary epithelium and vessels of the iris are unmodified. The lumen of the Schlemm canal is invaded by tracer-containing blood; through newly formed gaps in the endothelial lining of the inner wall of the canal, tracer rapidly diffuses into the jtixtacanalicidar connective tissue, trabecidar meshwork, and anterior chamber. The idea is therefore advanced that the sudden fall of the intraocular pressure upon aqueous humor withdrawal causes a reflux of blood from the episcleral veins itito the Schlemm canal and plasma proteins rapidly leak into the anterior chamber. On the basis of the present experiment, the widespread belief that the plasma proteins of the plasmoid aqueous humor originate from the ciliary epithelium or the iris is no longer acceptable. Paracentesis has no effect on the permeability properties of the junctions which represent the morphologic counterpart of the blood-aqueous barrier. It breaks the hydrodynamic equilibrium which ensures the unidirectional flow of the aqueous humor from the posterior chamber to the episcleral veins.