Centre for Ophthalmology, University of Tübingen, Tübingen, Germany.
Invest Ophthalmol Vis Sci. 2012 Aug 15;53(9):5552-61. doi: 10.1167/iovs.12-10037.
To examine the effects of transcorneal electrical stimulation (TES) on retinal degeneration of light-exposed rats.
Thirty-three Sprague Dawley albino rats were divided into three groups: STIM (n = 15) received 60 minutes of TES, whereas SHAM (n = 15) received identical sham stimulation 2 hours before exposure to bright light with 16,000 lux; healthy animals (n = 3) served as controls for histology. At baseline and weekly for 3 consecutive weeks, dark- and light-adapted electroretinography was used to assess retinal function. Analysis of the response versus luminance function retrieved the parameters Vmax (saturation amplitude) and k (luminance to reach ½Vmax). Retinal morphology was assessed by histology (hematoxylin-eosin [HE] staining; TUNEL assay) and immunohistochemistry (rhodopsin staining).
Vmax was higher in the STIM group compared with SHAM 1 week after light damage (mean intra-individual difference between groups 116.06 μV; P = 0.046). The b-wave implicit time for the rod response (0.01 cd.s/m²) was lower in the STIM group compared with the SHAM group 2 weeks after light damage (mean intra-individual difference between groups 5.78 ms; P = 0.023); no other significant differences were found. Histological analyses showed photoreceptor cell death (TUNEL and HE) in SHAM, most pronounced in the superior hemiretina. STIM showed complete outer nuclear layer thickness preservation, reduced photoreceptor cell death, and preserved outer segment length compared with SHAM (HE and rhodopsin).
This sham-controlled study shows that TES can protect retinal cells against mild light-induced degeneration in Sprague Dawley rats. These findings could help to establish TES as a treatment in human forms of retinal degenerative disease.
观察经角膜电刺激（TES）对光暴露大鼠视网膜变性的影响。
将 33 只 Sprague Dawley 白化大鼠分为三组：STIM（n = 15）组接受 60 分钟 TES，而 SHAM（n = 15）组在暴露于 16000lux 的强光前接受相同的假刺激 2 小时；健康动物（n = 3）作为组织学对照。在基线和连续 3 周的每周，暗适应和明适应视网膜电图用于评估视网膜功能。分析响应与亮度的函数，得出 Vmax（饱和幅度）和 k（达到 1/2Vmax 的亮度）参数。通过组织学（苏木精-伊红[HE]染色；TUNEL 检测）和免疫组织化学（视紫红质染色）评估视网膜形态。
与 SHAM 组相比，光损伤后 1 周 STIM 组的 Vmax 更高（组内个体差异平均值为 116.06μV；P = 0.046）。STIM 组在光损伤后 2 周的杆状反应的 b 波潜伏期（0.01 cd.s/m²）低于 SHAM 组（组内个体差异平均值为 5.78ms；P = 0.023）；未发现其他显著差异。组织学分析显示 SHAM 组存在光感受器细胞死亡（TUNEL 和 HE），以上部半视网膜最为明显。与 SHAM 组相比，STIM 组完整保留了外核层厚度，减少了光感受器细胞死亡，并保留了外节长度（HE 和视紫红质）。
这项假对照研究表明，TES 可以保护 Sprague Dawley 大鼠的视网膜细胞免受轻度光诱导的变性。这些发现有助于将 TES 确立为人类视网膜退行性疾病的治疗方法。
