de Oliveira Miguel Nadia Campos, Meyer-Rochow Victor Benno, Allodi Silvana
Departamento de Histologia e Embriologia, Centro de Ciencias da Saude (CCS), Instituto de Ciencias Biomedicas (ICB), Universidade Federal do Rio de Janeiro, Ilha do Fundão, 21941-590 Rio de Janeiro, RJ, Brazil.
Micron. 2003;34(8):395-404. doi: 10.1016/S0968-4328(03)00081-7.
Over the last two decades, ultraviolet radiation levels (UV), reaching the Earth's surface, have been increasing at a rate of 1.5% per each 1% loss of the ozone layer. Moreover, artificial UV-sources have also proliferated and contributed to the rising UV-stress that many organisms have to face. To assess how the vertebrate retina responds to an exposure of short wavelength UV, we focused our attention on the rat retina, observing photoreceptor (containing outer and inner segments of rods and cones), inner plexiform, and ganglion cell layers by light and transmission electron microscopy using conventional and cytochemical techniques. We analyzed how cells of the layers in question responded to a 30 min exposure to UV-C and UV-B radiation with doses of 7200 and 590 J/cm(2), respectively. The results show that there are significant changes in the nuclei and cytoplasmic organelles of the exposed retinae when compared with those of the unexposed controls. The changes include an increase in heterochromatin, distension of rough endoplasmic reticulum, mitochondrial disruptions, and increases in the number of myelin bodies. The recorded morphological changes, especially those of the ganglion cells, are suggestive of apoptotic processes and show that the exposure of vertebrate retina to wavelengths ranging from 254 to 312 nm can produce alterations that are likely to impact negatively on the retina's proper functioning.
在过去二十年中，到达地球表面的紫外线辐射水平（UV）随着臭氧层每减少1%而以1.5%的速率增加。此外，人工紫外线源也大量增加，导致许多生物体不得不面对日益增加的紫外线压力。为了评估脊椎动物视网膜对短波长紫外线照射的反应，我们将注意力集中在大鼠视网膜上，使用传统和细胞化学技术，通过光学显微镜和透射电子显微镜观察光感受器（包含视杆和视锥的外段和内段）、内网层和神经节细胞层。我们分析了上述各层细胞分别对剂量为7200 J/cm²的UV-C和590 J/cm²的UV-B辐射暴露30分钟后的反应。结果表明，与未暴露的对照组相比，暴露后的视网膜细胞核和细胞质细胞器有显著变化。这些变化包括异染色质增加、粗面内质网扩张、线粒体破坏以及髓鞘小体数量增加。所记录的形态学变化，尤其是神经节细胞的变化，提示了凋亡过程，表明脊椎动物视网膜暴露于254至312纳米波长范围的光线会产生可能对视网膜正常功能产生负面影响的改变。
