PURPOSE Retinal ganglion cells (RGCs) loss is closely related to visual impairment in glaucoma, so the neuroprotection on RGCs is important and novel for glaucoma research. SIRT1, a family member of sirtuins, is implicated in many crucial processes of eye diseases. The purpose of this study is to determine the neuroprotection of SIRT1 on RGCs and to investigate the underlying mechanisms of these effects in an experimental model for acute glaucoma. METHODS Retinal ischemia-reperfusion (IR) injury was induced in C57BL/6J mice. Resveratrol (RSV, activator of SIRT1) and sirtinol (inhibitor of SIRT1) were injected intravitreally 1 day before IR injury. RGCs survival rate was quantified by immunofluorescence staining. RGCs apoptosis was evaluated by the staining of TUNEL and cleaved caspase-3, and SIRT1 level was detected by western blot. Expressions of phospho-Akt, Akt, Bax, and Bcl-2 were further determined by western blot to investigate the neuroprotective mechanisms of SIRT1. RESULTS RGCs survival rates and SIRT1 levels were decreased over time after IR injury. Intravitreal injection of RSV remarkably attenuated RGCs loss in a dose-dependent manner, and the most effective concentration of RSV was 100 μM. Up-regulation of SIRT1 by RSV significantly inhibited RGCs apoptosis, increased p-Akt level, decreased Bax and cleaved caspase-3 expressions, and all these effects were diminished by 100 μM sirtinol. Moreover, there were no significant changes in total Akt and Bcl-2 levels. CONCLUSION SIRT1 activation by RSV confers neuroprotection on RGCs in retinal IR injury through the activation of Akt pathway and subsequent suppression of mitochondrial apoptotic pathway. Determination of the effective concentration of intravitreal injection of RSV also provides a theoretical basis for the clinical application of RSV.

中文翻译：

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SIRT1是白藜芦醇对小鼠视网膜缺血再灌注损伤后视网膜神经节细胞的神经保护所必需的。

目的视网膜神经节细胞（RGCs）的丧失与青光眼的视力损害密切相关，因此对RGC的神经保护对于青光眼的研究具有重要意义和新颖性。SIRT1，sirtuins的家庭成员，涉及许多重要的眼部疾病过程。这项研究的目的是确定SIRT1对RGC的神经保护作用，并研究急性青光眼实验模型中这些作用的潜在机制。方法C57BL / 6J小鼠诱发视网膜缺血再灌注（IR）损伤。IR损伤前1天，玻璃体内注射白藜芦醇（RSV，SIRT1的激活剂）和sirtinol（SIRT1的抑制剂）。通过免疫荧光染色定量RGC的存活率。通过TUNEL染色和裂解的caspase-3染色评估RGC的凋亡，并通过western blot检测SIRT1水平。通过Western印迹进一步确定磷酸化Akt，Akt，Bax和Bcl-2的表达，以研究SIRT1的神经保护机制。结果IR损伤后，RGC的存活率和SIRT1水平随时间降低。玻璃体内注射RSV以剂量依赖的方式显着降低了RGC的损失，RSV的最有效浓度为100μM。RSV对SIRT1的上调显着抑制了RGC的凋亡，增加了p-Akt的水平，降低了Bax并切割了caspase-3的表达，而所有这些作用都被100μM的西地洛酚所减弱。此外，总Akt和Bcl-2水平没有明显变化。结论RSV激活SIRT1可以通过激活Akt途径并随后抑制线粒体凋亡途径，对视网膜IR损伤的RGC赋予神经保护作用。