Nitric oxide synthase activity in retinas from non-insulin-dependent diabetic Goto-Kakizaki rats: Correlation with blood-retinal barrier permeability
Nitric oxide synthase activity in retinas from non-insulin-dependent diabetic Goto-Kakizaki rats: Correlation with blood-retinal barrier permeability
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DOI：
10.1006/niox.2000.0312
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发表时间：
2000-12-01
影响因子：
3.9
通讯作者：
Lopes, MC
中科院分区：
文献类型：
--
作者：
Carmo, A;Cunha-Vaz, JG;Lopes, MC
本研究的目的是研究非胰岛素依赖型糖尿病Goto-Kakizaki （GM）大鼠的视网膜变化是否与胰岛素依赖型糖尿病大鼠在血视网膜屏障（BRB）通透性、一氧化氮（NO）生成和视网膜IL-1 β水平方面观察到的特征相似。采用玻璃体荧光光度法评价BRB的通透性。采用L-[H-3]-瓜氨酸生成法检测NO合成酶（NOS）活性，ELISA法检测视网膜IL-1 β水平。采用Western blot和免疫组化检测NOS （iNOS）诱导异构体的表达情况。体内研究表明，与正常Wistar大鼠（646.6 +/- 55 min(-1)）相比，GK大鼠BRB对荧光素的通透性增加（788,81 +/- 68 min(-1)）。离体研究表明，GK大鼠视网膜NOS活性（207 +/- 28.9 pmol L-[H-3]-瓜氨酸/mg蛋白/ 30min）高于正常Wistar大鼠（125 +/- 32.3 pmol L-[H-3]-瓜氨酸/mg蛋白/ 30min）。这些结果与GK大鼠视网膜iNOS蛋白水平升高有关，这不仅可以通过iNOS蛋白表达的研究得到证实，也可以通过NOS活性抑制剂的使用得到证实。事实上，关于特异性抑制剂对NOS活性影响的数据显示，在GK大鼠的视网膜中，最有效的抑制剂是氨基胍，它主要抑制iNOS异构体，而在正常Wistar大鼠的视网膜中，主要抑制NOS组成异构体的是N-G硝基l -精氨酸。总之，在GK大鼠的视网膜中，NO的产生增加，这可能有助于BRB的分解。(C) 2000年学术出版社。
The aim of this work was to examine whether the non-insulin-dependent diabetic Goto-Kakizaki (GM) rats develop retinal changes with similar characteristics to those observed in insulin-dependent diabetic rats in what concerns blood-retinal barrier (BRB) permeability, nitric oxide (NO) production, and retinal IL-1 beta level. BRB permeability was evaluated by vitreous fluorophotometry. NO synthase (NOS) activity was assessed by the production of L-[H-3]-citrulline and retinal IL-1 beta level was determined by ELISA. The expression of the inducible isoform of NOS (iNOS) protein was evaluated by Western blot analysis and immunohistochemistry. The in vivo studies indicated that in GK rats the BRB permeability to fluorescein was increased (787,81 +/- 68 min(-1)) in comparison to that in normal Wistar rats (646.6 +/- 55 min(-1)). The ex vivo studies showed that in retinas from GK rats the NOS activity was higher (207 +/- 28.9 pmol L-[H-3]-citrulline/mg protein/30 min) than that in normal Wistar rats (125 +/- 32.3 pmol L-[H-3]-citrulline/mg protein/30 min). These results were correlated with an increase in the protein level of iNOS in the retinas of GK rats, which was confirmed not only by the study of the iNOS protein expression but also by the use of NOS activity inhibitors. Indeed, the data about the effect of specific inhibitors on the NOS activity revealed that in retinas from GK rats the most effective inhibitor was aminoguanidine, which predominantly inhibits the iNOS isoform whereas in retinas from normal Wistar rats it was N-G nitro L-arginine that predominantly inhibits the constitutive isoforms of NOS. In summary, in retinas from GK rats there is an increased production of NO which may contribute to the BRB breakdown. (C) 2000 Academic Press.