Do carmo A, Ramos P, Reis A, Proença R, Cunha-vaz J G
Centre of Ophthalmology, Institute for Biomedical Research of Light and Image, University of Coimbra, Coimbra, Portugal.
Exp Eye Res. 1998 Nov;67(5):569-75. doi: 10.1006/exer.1998.0546.
Using vitreous fluorophotometry and quantitative fluorescence microscopy the authors studied the permeability of the blood-retinal barrier (BRB) to fluorescein in control and in 8 days streptozotocin-induced diabetic rats. Vitreous fluorophotometry showed that fluorescein permeates BRB in control and in diabetic rats. However, in diabetic rats the permeability to fluorescein was significantly increased as compared to control rats. The vitreous penetration ratio (VPR) values for total and free fluorescein at 60 min, were higher for diabetic rats (231.2+/-12.9 min-1 for total fluorescein and 1299.24+/-58.0 min-1 for free fluorescein) than for control rats (95.5+/-3.5 min-1 for total fluorescein and 646.6+/-55. 0 min-1 for free fluorescein) (P<0.05). Quantitative confocal fluorescence microscopy confirmed these findings and identified the site of leakage across the BRB by comparing the relative importance of the fluorescein leakage across the outer and inner BRB. In control rats the fluorescence levels remained relatively low in the photoreceptor layer, next to the outer BRB but in the inner nuclear layer, next to the inner BRB reached values that were almost ten times higher. These results suggest that in retinas of control rats fluorescein penetrates predominantly through the inner BRB. In diabetic rats the fluorescence levels in the photoreceptor and in the inner nuclear layer were significantly increased as compared to the fluorescence levels in controls rats. Nevertheless, in the inner nuclear layer the fluorescence levels were also generally higher than the fluorescence levels at the photoreceptor layer. The rates of fluorescence levels between the inner nuclear layer and the photoreceptor layer were apparently 3:1, 60 min after the single intravenous injection of fluorescein. Also, the fluorescein penetration in the inner nuclear layer of the diabetic rats is higher than that observed in the inner nuclear layer of the control rats (P<0.001). These findings suggest that the permeability to fluorescein of both components of the BRB is increased 8 days after the induction of diabetes by streptozotocin and that the permeability of the retinal vasculature is preferentially affected.
作者使用玻璃体荧光光度法和定量荧光显微镜，研究了正常对照大鼠以及经链脲佐菌素诱导糖尿病8天的大鼠血视网膜屏障（BRB）对荧光素的通透性。玻璃体荧光光度法显示，荧光素可透过正常对照大鼠和糖尿病大鼠的BRB。然而，与正常对照大鼠相比，糖尿病大鼠对荧光素的通透性显著增加。糖尿病大鼠在60分钟时总荧光素和游离荧光素的玻璃体渗透比（VPR）值（总荧光素为231.2±12.9 min-1，游离荧光素为1299.24±58.0 min-1）高于正常对照大鼠（总荧光素为95.5±3.5 min-1，游离荧光素为646.6±55.0 min-1）（P<0.05）。定量共聚焦荧光显微镜证实了这些发现，并通过比较荧光素透过外BRB和内BRB渗漏的相对重要性，确定了BRB渗漏的部位。在正常对照大鼠中，紧邻外BRB的光感受器层荧光水平相对较低，但紧邻内BRB的内核层荧光水平几乎高出十倍。这些结果表明，在正常对照大鼠视网膜中，荧光素主要通过内BRB渗透。与正常对照大鼠的荧光水平相比，糖尿病大鼠光感受器层和内核层的荧光水平显著增加。然而，在内核层，荧光水平通常也高于光感受器层的荧光水平。单次静脉注射荧光素60分钟后，内核层与光感受器层的荧光水平比率明显为3:1。此外，糖尿病大鼠内核层的荧光素渗透率高于正常对照大鼠内核层（P<0.001）。这些发现表明，链脲佐菌素诱导糖尿病8天后，BRB的两个组成部分对荧光素的通透性均增加，且视网膜血管系统的通透性受到的影响更为显著。
