Goldschleger Eye Institute, Sheba Medical Center, Tel-Hashomer, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel,
Graefes Arch Clin Exp Ophthalmol. 2014 May;252(5):761-72. doi: 10.1007/s00417-014-2588-4. Epub 2014 Feb 25.
Minocycline, a second-generation tetracycline with anti-inflammatory and anti-apoptotic properties, was reported to be neuroprotective in experimental glaucoma and optic nerve transection as well as in other neurodegenerative diseases. The purpose of this study was to investigate the mechanism underlying that neuroprotective effect in murine glaucoma.
Elevated intraocular pressure was induced in 159 rats by the translimbal photocoagulation laser model. Minocycline 22 mg/kg or saline was injected intraperitoneally starting 3 days before the induction of glaucoma, and continued daily until the animals were sacrificed. The effect of minocycline on gene expression was evaluated using a quantitative polymerase chain reaction (PCR) array for apoptosis. The involvement of selected pro-apoptotic, pro-survival, and inflammatory genes was further analyzed by quantitative real-time PCR at multiple time points. Immunohistochemistry was used to study the effect of minocycline on microglial activation and to localize Bcl-2 changes.
Minocycline significantly increased the anti-apoptotic gene Bcl-2 expression at day 8 and day 14 after the induction of glaucoma (p = 0.04 and p = 0.03 respectively), and decreased IL-18 expression in the retina at day 14 and day 30 (p = 0.04 and p < 0.001 respectively). PCR arrays suggested that additional genes were affected by minocycline, including Tp53bp2, TRAF4, osteoprotegerin, caspase 1 and 4, and members of the tumor necrosis factor superfamily. Additionally, minocycline decreased the amount of activated microglia in glaucomatous eyes.
These results suggest that minocycline upregulates pro-survival genes and downregulates apoptotic genes, thus shifting the balance toward the anti-apoptotic side in experimental glaucoma.
米诺环素是一种具有抗炎和抗细胞凋亡特性的第二代四环素，据报道在实验性青光眼和视神经横断以及其他神经退行性疾病中具有神经保护作用。本研究旨在探讨米诺环素在实验性青光眼中发挥神经保护作用的机制。
通过经巩膜光凝激光模型在 159 只大鼠中诱导眼内压升高。在青光眼诱导前 3 天开始，通过腹腔内注射米诺环素 22mg/kg 或生理盐水，并持续每日注射直至动物处死。使用凋亡定量聚合酶链反应（PCR）阵列评估米诺环素对基因表达的影响。通过定量实时 PCR 在多个时间点进一步分析选定的促凋亡、促存活和炎症基因的参与情况。免疫组织化学用于研究米诺环素对小胶质细胞激活的影响，并定位 Bcl-2 变化。
米诺环素在青光眼诱导后第 8 天和第 14 天显著增加了抗凋亡基因 Bcl-2 的表达（分别为 p=0.04 和 p=0.03），并在第 14 天和第 30 天降低了视网膜中 IL-18 的表达（分别为 p=0.04 和 p<0.001）。PCR 阵列表明，米诺环素还影响了其他基因，包括 Tp53bp2、TRAF4、骨保护素、半胱天冬酶 1 和 4 以及肿瘤坏死因子超家族成员。此外，米诺环素减少了青光眼眼中激活的小胶质细胞的数量。
这些结果表明，米诺环素上调了促存活基因并下调了凋亡基因，从而在实验性青光眼中使平衡向抗凋亡方向倾斜。
