Department of Ophthalmology, Changhai Hospital, Shanghai, China.
J Neurotrauma. 2010 Apr;27(4):763-70. doi: 10.1089/neu.2009.1005.
In this study we tested the hypothesis that hyperbaric oxygen preconditioning (HBO-PC) reduces retinal neuronal death due to optic nerve crush (ONC). Adult male Sprague-Dawley rats were subjected to ONC accompanied by a contralateral sham operation. HBO-PC was conducted four times by giving 100% oxygen at 2.5 atmospheres absolute (ATA) for 1 h every 12 h for 2 days prior to ONC. The rats were euthanized at 1 or 2 weeks after ONC. Retinal ganglion cell (RGC) density was counted by hematoxylin and eosin (H&E) staining of the retina and retrograde labeling with FluoroGold application to the superior colliculus. Visual function was assessed by flash visual evoked potentials (FVEP). TUNEL straining and caspase-3 and caspase-9 activity in the retinas were assessed. The RGC density in the retinas of ONC HBO-PC-treated rats was significantly higher than that of the corresponding ONC-only rats (the survival rate was 67.2% versus 49.7% by H&E staining, and 60.3% versus 28.9% by retrograde labeling with FluoroGold, respectively; p < 0.01) at 2 weeks after ONC. FVEP measurements indicated a significantly better preserved latency and amplitude of the P1 wave in the ONC HBO-PC-treated rats than the ONC-only rats (92 +/- 7 msec, 21 +/- 3 microv in the sham-operated group, 117 +/- 12 msec, 14 +/- 2 microv in the HBO-PC-treated group, and 169 +/- 15 msec, 7 +/- 1 microv in the corresponding ONC group; p < 0.01). TUNEL assays showed fewer apoptotic cells in the HBO-PC-treated group, accompanied by the suppression of caspase-3 and caspase-9 activity. These results demonstrate that HBO-PC appears to be neuroprotective against ONC insult via inhibition of neuronal apoptosis pathways.
在这项研究中，我们检验了这样一个假设，即高压氧预处理（HBO-PC）可减少视神经挤压（ONC）引起的视网膜神经元死亡。成年雄性 Sprague-Dawley 大鼠接受 ONC 治疗，并同时进行对侧假手术。在 ONC 前 2 天，每 12 小时给予 100%氧气，在 2.5 个大气压（ATA）下治疗 1 小时，共进行 4 次 HBO-PC。大鼠在 ONC 后 1 或 2 周处死。通过视网膜的苏木精和伊红（H&E）染色和荧光金在视上丘的逆行标记来计数视网膜神经节细胞（RGC）密度。通过闪光视觉诱发电位（FVEP）评估视觉功能。评估视网膜中的 TUNEL 染色和 caspase-3 和 caspase-9 活性。ONC HBO-PC 治疗大鼠的视网膜 RGC 密度明显高于相应的仅 ONC 大鼠（H&E 染色的存活率分别为 67.2%和 49.7%，荧光金逆行标记的存活率分别为 60.3%和 28.9%；p<0.01）在 ONC 后 2 周。FVEP 测量表明，与仅 ONC 大鼠相比，ONC HBO-PC 治疗大鼠的 P1 波潜伏期和振幅得到了显著改善（假手术组为 92 +/- 7 msec，21 +/- 3 microv；HBO-PC 治疗组为 117 +/- 12 msec，21 +/- 3 microv；14 +/- 2 microv；相应的 ONC 组为 169 +/- 15 msec，7 +/- 1 microv；p<0.01）。TUNEL 检测显示 HBO-PC 治疗组凋亡细胞较少，同时抑制 caspase-3 和 caspase-9 活性。这些结果表明，HBO-PC 似乎通过抑制神经元凋亡途径对 ONC 损伤具有神经保护作用。
