Zou Xiu-Lan, Yu Yong-Zhen, Yu Hong-Hua, Wang Guan-Feng, Pi Rong-Biao, Xu Zhe, Zhang Chu, Zhou Wen-Jie, Li Dan-Dan, Chen Xuan-Ge, Zou Yu-Ping
Department of Ophthalmology, General Hospital of Southern Theatre Command of PLA, Guangzhou 510010, Guangdong Province, China.
Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangzhou 510000, Guangdong Province, China.
Int J Ophthalmol. 2019 Aug 18;12(8):1262-1271. doi: 10.18240/ijo.2019.08.05. eCollection 2019.
To evaluate the protective effects of lipoic acid-niacin (N2L) dimers against blue light (BL)-induced oxidative damage to human retinal pigment epithelium (hRPE) cells
hRPE cells were divided into a control group (CG), a BL group, an N2L plus BL irradiation group, an α-lipoic acid (ALA) plus BL group, an ALA-only group, and an N2L-only group. hRPE cellular viability was detected by performing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) bromide assays, and apoptosis was evaluated by annexin-V-PE/7-AAD staining followed by flow cytometry. Ultrastructural changes in subcellular organelles were observed by transmission electron microscopy. Reactive oxygen species formation was assayed by flow cytometry. The expression levels of the apoptosis-related proteins BCL-2 associated X protein (BAX), B-cell leukmia/lymphoma 2 (BCL-2), and caspase-3 were quantified by Western blot analysis.
BL exposure with a light density of 4±0.5 mW/cm exceeding 6h caused hRPE toxicity, whereas treatment with a high dose of N2L (100 mol/L) or ALA (150 mol/L) maintained cell viability at control levels. BL exposure caused vacuole-like degeneration, mitochondrial swelling, and reduced microvillus formation; however, a high dose of N2L or ALA maintained the ultrastructure of hRPE cells and their organelles. High doses of N2L and ALA also protected hRPE cells from BL-induced apoptosis, which was confirmed by Western blot analysis: BCL-2 expression significantly increased, while BAX and caspase-3 expression slightly decreased compared to the CG.
High-dose N2L treatment (>100 mol/L) can reduce oxidative damage in degenerating hRPE cells exposed to BL with an efficacy similar to ALA.
评估硫辛酸 - 烟酸（N2L）二聚体对蓝光（BL）诱导的人视网膜色素上皮（hRPE）细胞氧化损伤的保护作用
将hRPE细胞分为对照组（CG）、蓝光组、N2L加蓝光照射组、α - 硫辛酸（ALA）加蓝光组、仅ALA组和仅N2L组。通过3 -（4,5 - 二甲基噻唑 - 2 - 基）- 2,5 - 二苯基四氮唑溴盐（MTT）法检测hRPE细胞活力，通过膜联蛋白 - V - PE/7 - AAD染色后流式细胞术评估细胞凋亡。通过透射电子显微镜观察亚细胞器的超微结构变化。通过流式细胞术测定活性氧的形成。通过蛋白质印迹分析定量凋亡相关蛋白B细胞淋巴瘤 - 2相关X蛋白（BAX）、B细胞白血病/淋巴瘤2（BCL - 2）和半胱天冬酶 - 3的表达水平。
光密度为4±0.5 mW/cm的蓝光暴露超过6小时会导致hRPE细胞毒性，而高剂量的N2L（100 μmol/L）或ALA（150 μmol/L）处理可将细胞活力维持在对照水平。蓝光暴露导致空泡样变性、线粒体肿胀和微绒毛形成减少；然而，高剂量的N2L或ALA维持了hRPE细胞及其细胞器的超微结构。高剂量的N2L和ALA还保护hRPE细胞免受蓝光诱导的凋亡，蛋白质印迹分析证实：与CG相比，BCL - 2表达显著增加，而BAX和半胱天冬酶 - 3表达略有下降。
高剂量N2L处理（>100 μmol/L）可减少暴露于蓝光的退变hRPE细胞中的氧化损伤，其效果与ALA相似。
