Study of fluid dynamics in the vitreous in normal and pathological eges

众所周知，玻璃体内的流体动力学取决于视网膜色素上皮（RPE）的功能。我们已经报道了荧光素在分离兔RPE-脉络膜上使用Ussing腔的运动模式的特征，并且该系统适合于研究RPE的功能，即主动运输功能和抵抗外源物质扩散的屏障功能。这一次，我们研究了羧基荧光素在离体兔rpe -脉络膜上运动模式的特征。在研究细胞层的屏障功能方面，羧基荧光素是一种更好的示踪染料，预计通过计算RPE对羧基荧光素的渗透系数可以间接猜测RPE上的流体运动。羧基荧光素通过离体rpe -脉络膜从脉络膜向玻璃体一侧移动（向内移动）是通过被动扩散，而从玻璃体向脉络膜一侧移动（向外移动）部分是通过主动运输。在30mum浓度下，离体兔rpe -脉络膜对羧基荧光素的向外通透性约为向内通透性的两倍。Probenecid、瓦巴因、2,4-二硝基苯酚和hippurate显著降低了对羧基荧光素的外透性。饱和动力学研究表明，羧基荧光素对载体的亲和力和最大反应速度低于荧光素。BSS+GSSG对羧基荧光素的向内通透性显著低于BSS和Krebs’Ringer溶液，说明氧化谷胱甘肽GSSG对RPE的屏障功能有有益作用。羧基荧光素和Ussing室的使用被认为是研究与RPE的流体运动和RPE的屏障功能相关的主动传递功能的有用工具。

It is well known that fluid dynamics in the vitreous depends on the function of retinal pigment epithelium (RPE). We already reported characteristics of mode of fluorescein movement across the isolated rabbit RPE-choroid using Ussing's chamber and that this system is suited for studying the functions of RPE, i.e., active transporting function and barrier function against diffusion of exogenous substances. This time, we studied characteristics of mode of carboxyfluorescein movement across the isolated rabbit RPE-choroid. Carboxyfluorescein is known to be a much better tracer dye in studying the barrier function of cell layrs and it is expected that fluid movement across the RPE can be indirectly guessed by calculating the permeability coefficient of RPE to carboxyfluorescein.Movement of carboxyfluorescein across the isolated RPE-choroid from the choroid to the vitreous side (Inward movement) was found to be by passive diffusion, while its movement from the vitreous to the choroid side (Outward movement) was partly by active transport. At concentration of 30 muM, outward permeability of the isolated rabbit RPE-choroid to carboxyfluorescein was about twice of the inward permeability. Probenecid, ouabain, 2,4-dinitrophenol and hippurate significantly reduced the outward permeability to carboxyfluorescein. A saturation kinetic study revealed that affinity and maximum velocity of reaction of carboxyfluorescein to the carrier is lower than that of fluorescein. The inward permeability to carboxyfluorescein was significantly lower in BSS+GSSG than in BSS or Krebs' Ringer solution, which suggested that GSSG, oxidized glutathione, has beneficial effects on the barrier function of the RPE.The usage of carboxyfluorescein and Ussing's chamber is suggested to be a useful tool for studying active transport function which is associated with fluid movement across the RPE and barrier function of the RPE.