Department of Ophthalmology, Buddhist Tzu Chi General Hospital, Hualien, Taiwan.
Exp Eye Res. 2011 Feb;92(2):112-9. doi: 10.1016/j.exer.2010.12.008. Epub 2010 Dec 24.
The purpose of the present study was to investigate the effects of administrations of triamcinolone acetonide and systemic methylprednisolone sodium succinate on optic nerves (ON) and retinal ganglion cells (RGC) in a rat model of optic nerve crush. The treated groups either received triamcinolone immediately in the form of two pieces of soaked-gelform surrounding retrobulbar optic nerves (0.5 mg/per gelform) or methylprednisolone via peritoneal injection, and control group received intra-peritoneal injection with phosphate-buffered saline (PBS) after crush experiments. RGC density was counted by retrograde labeling with Fluorogold, and visual function was assessed by flash visual-evoked potentials. Terminal transferase dUTP nick end-labeling (TUNEL) assays, Western blot analysis of serine/threonine kinase (p-Akt), extracellular signal-regulated kinases (p-ERK) and signal transducer and activator of transcription 3 (p-STAT3) and immunohistochemistry of ED1, marker of macrophage/microglia in the optic nerve were conducted. Two and four weeks after optic nerve crush experiments, neither triamcinolone nor methylprednisolone treatment rescued the RGC from death in the central and mid-peripheral retinas compared with those of the corresponding optic nerve-crushed and PBS-treated rats. Visual-evoked potentials measurements showed a prolonged latency of the P(1) wave in all treated groups (triamcinolone-treated: 123 ± 23 ms, methylprednisolone-treated: 133 ± 25 ms and PBS-treated: 151 ± 55 ms) after two weeks. TUNEL assays showed that there was no decrease in apoptotic cells in the RGC layers of both triamcinolone treated and methylprednisolone-treated retinas. Western blot analysis showed that p-AKT, p-ERK and p-Stat3 were not up-regulated in either retina of the triamcinolone or methylprednisolone treated rats. In addition, the number of ED1-positive cells was not attenuated at the lesion sites of the ON in either treatment group. Based upon these results, we conclude that neither retrobulbar administration of triamcinolone nor systemic administration of methylprednisolone has any neuroprotective effects in a rat model of optic nerve crush.
本研究旨在探讨曲安奈德和甲基强的松龙琥珀酸钠对大鼠视神经挤压模型视神经（ON）和视网膜神经节细胞（RGC）的影响。实验组或立即在球后视神经周围给予曲安奈德（每凝胶形式 0.5mg/块），或通过腹腔注射给予甲基强的松龙，对照组在挤压实验后给予腹腔注射磷酸盐缓冲盐水（PBS）。通过逆行标记荧光金计数 RGC 密度，并通过闪光视觉诱发电位评估视觉功能。末端转移酶 dUTP 缺口末端标记（TUNEL）检测、丝氨酸/苏氨酸激酶（p-Akt）、细胞外信号调节激酶（p-ERK）和信号转导和转录激活因子 3（p-STAT3）的 Western blot 分析以及视神经中巨噬细胞/小胶质细胞标志物 ED1 的免疫组织化学检测。视神经挤压实验后 2 周和 4 周，与相应视神经挤压和 PBS 处理的大鼠相比，曲安奈德或甲基强的松龙治疗均不能挽救中央和中周视网膜的 RGC 死亡。视觉诱发电位测量显示，所有治疗组（曲安奈德治疗组：123±23ms，甲基强的松龙治疗组：133±25ms 和 PBS 治疗组：151±55ms）在 2 周后 P（1）波潜伏期延长。TUNEL 检测显示，曲安奈德治疗和甲基强的松龙治疗的视网膜 RGC 层中凋亡细胞没有减少。Western blot 分析显示，曲安奈德或甲基强的松龙治疗的大鼠视网膜中 p-AKT、p-ERK 和 p-Stat3 均未上调。此外，在任何治疗组的视神经病变部位，ED1 阳性细胞的数量均未减少。基于这些结果，我们得出结论，球后给予曲安奈德或全身给予甲基强的松龙对大鼠视神经挤压模型均没有神经保护作用。
