Department of Ophthalmology, Second Hospital of JiLin University, ChangChun 130041, China.
Department of Hemooncolog, Second Hospital of JiLin University, ChangChun 130041, China.
Free Radic Biol Med. 2018 Dec;129:569-581. doi: 10.1016/j.freeradbiomed.2018.10.431. Epub 2018 Oct 18.
Retinal degeneration is a major cause of severe vision loss and irreversible blindness and is characterized by progressive damage to retinal photoreceptor cells. Resveratrol (RSV) serves as an activator of the histone deacetylase, Sirt1, and has been shown to exert anti-oxidative properties. In this study, we mimicked retinal degeneration by subjecting photoreceptors (661 W cells) to glucose deprivation (GD) or light exposure. Under these conditions, we investigated the mechanisms underlying GD- or light exposure-induced cell death and the protective effect of RSV. We found that GD and light exposure resulted in mitochondrial dysfunction, oxidative stress, and cell death. Treatment of injured cells with RSV decreased the production of reactive oxygen species (ROS), improved the ratio of reduced/oxidized glutathione (GSH/GSSG), mitochondrial membrane potential and morphology, and reduced apoptosis. We used the caspase inhibitor, z-VAD-fmk, and a lentiviral-mediated shRNA knockdown of PARP-1 to reveal that GD and light exposure-induced cell death have different underlying mechanisms; GD triggered a caspase-dependent cell death pathway, whereas light exposure triggered a PARP-dependent cell death pathway. The level of caspase-9 and caspase-3, upregulated following GD, were reduced by treatment with RSV. Similarly, the level of PARP-1 and AIF, upregulated following light exposure, were decreased by treatment with RSV. Additionally, treatment with RSV elevated the protein expression and enzymatic activity of Sirt1 and a Sirt1 inhibitor reduced the protective effect of RSV against insult-induced cellular injuries, indicating that RSV's protective effect may involve Sirt1 activation. Finally, we investigated the neuroprotection of RSV in vivo. Administration of RSV to mice under extreme light exposure led to a suppression of the light-induced thinning of the outer nuclear layer (ONL) detected by hematoxylin and eosin (H&E) staining and restored retinal function evaluated by electroretinography (ERG). Taken together, our findings provide evidence that treatment with RSV has neuroprotective effects on both GD and light exposure-induced cell death pathways in photoreceptor cells.
视网膜变性是严重视力丧失和不可逆失明的主要原因，其特征是视网膜光感受器细胞进行性损伤。白藜芦醇（RSV）是组蛋白去乙酰化酶 Sirt1 的激活剂，已被证明具有抗氧化特性。在这项研究中，我们通过使光感受器（661W 细胞）遭受葡萄糖剥夺（GD）或光暴露来模拟视网膜变性。在这些条件下，我们研究了 GD 或光暴露诱导的细胞死亡的机制以及 RSV 的保护作用。我们发现，GD 和光暴露导致线粒体功能障碍、氧化应激和细胞死亡。用 RSV 处理受伤细胞可减少活性氧（ROS）的产生，改善还原型/氧化型谷胱甘肽（GSH/GSSG）、线粒体膜电位和形态的比值，并减少细胞凋亡。我们使用半胱天冬酶抑制剂 z-VAD-fmk 和慢病毒介导的 PARP-1 shRNA 敲低来揭示 GD 和光暴露诱导的细胞死亡具有不同的潜在机制；GD 触发了 caspase 依赖性细胞死亡途径，而光暴露触发了 PARP 依赖性细胞死亡途径。用 RSV 处理后，GD 后上调的 caspase-9 和 caspase-3 水平降低。同样，用 RSV 处理后，光暴露后上调的 PARP-1 和 AIF 水平降低。此外，用 RSV 处理可提高 Sirt1 的蛋白表达和酶活性，而 Sirt1 抑制剂可降低 RSV 对损伤诱导的细胞损伤的保护作用，表明 RSV 的保护作用可能涉及 Sirt1 激活。最后，我们研究了 RSV 在体内的神经保护作用。在极端光暴露下给小鼠施用 RSV 可抑制苏木精和曙红（H&E）染色检测到的外核层（ONL）的光诱导变薄，并通过视网膜电图（ERG）评估恢复视网膜功能。总之，我们的研究结果提供了证据，表明 RSV 治疗对光感受器细胞中 GD 和光暴露诱导的细胞死亡途径均具有神经保护作用。
