Piehl L, Capani F, Facorro G, López E M, de Celis E Rubin, Pustovrh C, Hager A, Coirini H, López-Costa J J
Cátedra de Física, Facultad de Farmacia y Bioquímica, UBA. Lanais RLBM, Argentina.
Brain Res. 2007 Jul 2;1156:112-9. doi: 10.1016/j.brainres.2007.04.030. Epub 2007 Apr 18.
Continuous illumination (CI) of the retina induces an oxidative stress followed by the degeneration of photoreceptors. This phenomenon may be partially related to the excessive production of nitric oxide (NO). In order to confirm this hypothesis, the aims of this work are to determine NO levels during the illumination of the retina by electron paramagnetic resonance (EPR), and if an increase of NO is found, to characterize the NOS isoform responsible of the increment by using Western blot. Sprague-Dawley rats were continuously illuminated with white light (12,000 lux) for 2, 24, 48 h, 5 and 7 days while control rats were maintained at light/dark cycles of 12/12 h. Using EPR, an increase of NO signal was observed in the light exposed retinas peaking at 24 h of CI. Western blot analysis showed the expression of iNOS in the illuminated retinas with a peak after 24 h of CI, but did not show significant differences of nNOS among illuminated and control retinas. In summary, there is an increase of NO during CI. Further studies will reveal whether this mechanism is responsible for light induced photoreceptor degeneration.
视网膜持续光照（CI）会引发氧化应激，随后导致光感受器退化。这种现象可能部分与一氧化氮（NO）的过量产生有关。为了证实这一假设，本研究的目的是通过电子顺磁共振（EPR）测定视网膜光照期间的NO水平，并且如果发现NO增加，则使用蛋白质印迹法来鉴定导致其增加的一氧化氮合酶（NOS）同工型。将Sprague-Dawley大鼠用白光（12,000勒克斯）持续照射2、24、48小时、5天和7天，而对照大鼠保持在12/12小时的明/暗循环中。使用EPR观察到，在光照的视网膜中NO信号增加，在CI 24小时时达到峰值。蛋白质印迹分析显示，光照视网膜中有诱导型一氧化氮合酶（iNOS）的表达，在CI 24小时后达到峰值，但在光照视网膜和对照视网膜之间，神经元型一氧化氮合酶（nNOS）没有显著差异。总之，CI期间NO增加。进一步的研究将揭示这种机制是否是光诱导的光感受器退化的原因。
