Imai Daisuke, Yoneya Shin, Gehlbach Peter L, Wei Lisa L, Mori Keisuke
Department of Ophthalmology, Saitama Medical School, Iruma, Saitama, Japan.
J Cell Physiol. 2005 Feb;202(2):570-8. doi: 10.1002/jcp.20155.
In this study, we investigated whether intraocular gene transfer of pigment epithelium-derived factor (PEDF) ameliorates the extent of light-induced photoreceptor cell death. Lewis rats received intravitreous injection of 3 x 10(9) particles of adenoviral vector expressing PEDF (AdPEDF.11) in one eye and 3 x 10(9) particles of empty adenoviral vector (AdNull.11) in the contralateral eye. The rats were then dark-adapted for 3 days after which they were continuously exposed to fluorescent light (2,500 lux) for 0, 6, 24, 96, and 168 h. Both eyes were then enucleated and processed for morphometric analysis. Cell death in the retina was examined using TUNEL staining with a propidium iodide counterstain. The photoreceptor cell counts in each of the three groups were significantly different (P < 0.001). Eyes that received intravitreous injection of AdNull.11 or no injection showed a greater number of pyknotic photoreceptor cells and a reduced photoreceptor cell density as compared to eyes treated with intravitreous AdPEDF.11 injection. AdNull.11 treated eyes showed a lesser but still significant protection of photoreceptor cells when compared to untreated eyes. Fewer TUNEL-positive photoreceptor cells were present in AdPEDF.11 treated eyes than in AdNull.11 treated or untreated eyes (P = 0.004). The amplitudes of the ERG a-wave, b-wave, and oscillatory potentials (OPs) were increased significantly by treatment (P < 0.05). These data suggest that adenovirus vector-mediated intraocular expression of PEDF significantly increases photoreceptor cell survival following excessive light exposure. Neuroprotection may result from inhibition of light-induced apoptotic processes. This study provides proof of concept for a gene transfer approach to modulating retinal cell death resulting from photo-oxidative damage and supports the hypothesis that gene transfer of PEDF is broadly applicable to modulating apoptosis in the retina.
在本研究中，我们调查了色素上皮衍生因子（PEDF）的眼内基因转移是否能减轻光诱导的光感受器细胞死亡程度。Lewis大鼠一只眼玻璃体内注射3×10⁹个表达PEDF的腺病毒载体颗粒（AdPEDF.11），对侧眼注射3×10⁹个空腺病毒载体颗粒（AdNull.11）。然后大鼠暗适应3天，之后连续暴露于荧光（2500勒克斯）下0、6、24、96和168小时。然后摘除双眼并进行形态计量分析。使用碘化丙啶复染的TUNEL染色检查视网膜中的细胞死亡情况。三组中每组的光感受器细胞计数有显著差异（P<0.001）。与玻璃体内注射AdPEDF.11治疗的眼睛相比，接受玻璃体内注射AdNull.11或未注射的眼睛显示出更多的固缩光感受器细胞且光感受器细胞密度降低。与未治疗的眼睛相比，AdNull.11治疗的眼睛对光感受器细胞的保护作用较小但仍显著。AdPEDF.11治疗的眼睛中TUNEL阳性光感受器细胞比AdNull.11治疗或未治疗的眼睛少（P = 0.004）。治疗显著增加了视网膜电图a波、b波和振荡电位（OPs）的振幅（P<0.05）。这些数据表明，腺病毒载体介导的眼内PEDF表达显著增加了过度光照后光感受器细胞的存活率。神经保护可能源于对光诱导凋亡过程的抑制。本研究为基因转移方法调节光氧化损伤导致的视网膜细胞死亡提供了概念验证，并支持PEDF基因转移广泛适用于调节视网膜凋亡的假说。
