Taarnhöj J, Alm A
Department of Ophthalmology, University Hospital, Uppsala, Sweden.
Graefes Arch Clin Exp Ophthalmol. 1992;230(6):589-91. doi: 10.1007/BF00181783.
Both active transport through and permeability of the blood-retinal barrier (BRB) are affected by sodium iodate, while the blood-brain barrier (BBB) is more resistant. We studied the effect of sodium iodate on facilitated diffusion through the two barriers. The retinal (RUI) and brain (BUI) uptake indices were determined for D-glucose and two neutral amino acids in normal and sodium iodate-treated rats. The integrity of the barriers was estimated by RUI and BUI for L-glucose and by measuring tissue uptake of L-glucose after an intravenous injection. We found that 30 mg/kg sodium iodate had no effect on transport through or permeability of the BBB, while 20 mg/kg significantly (P < 0.02) reduced transport of D-glucose, but not amino acids, through the BRB 1 h after injection. After 24 h both 20 mg/kg and 30 mg/kg sodium iodate caused a significant disruption of the BRB (P < 0.005 and P < 0.001, respectively). Thus, sodium iodate selectively affects the carrier for D-glucose in the BRB but not in the BBB. The presence of an epithelial part in the BRB, the retinal pigment epithelium, may explain the difference between the two barriers.
碘酸钠会影响血视网膜屏障（BRB）的主动转运和通透性，而血脑屏障（BBB）对碘酸钠更具抗性。我们研究了碘酸钠对通过这两种屏障的易化扩散的影响。测定了正常大鼠和经碘酸钠处理的大鼠中D-葡萄糖和两种中性氨基酸的视网膜摄取指数（RUI）和脑摄取指数（BUI）。通过L-葡萄糖的RUI和BUI以及静脉注射后测量L-葡萄糖的组织摄取来评估屏障的完整性。我们发现，30mg/kg碘酸钠对BBB的转运或通透性没有影响，而20mg/kg碘酸钠在注射后1小时显著（P<0.02）降低了D-葡萄糖通过BRB的转运，但对氨基酸没有影响。24小时后，20mg/kg和30mg/kg碘酸钠均导致BRB的显著破坏（分别为P<0.005和P<0.001）。因此，碘酸钠选择性地影响BRB中D-葡萄糖的载体，而不影响BBB中的载体。BRB中存在上皮部分，即视网膜色素上皮，可能解释了这两种屏障之间的差异。
