藍光照射合併光敏感物質A2E對人類視網膜上皮細胞之傷害效應

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2019

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A2E (N-retinylidene-N-retinylethanolamine)為眼睛視循環之維生素A衍生物,可隨人體老化與褐脂質 (lipofuscin)漸進式地堆積於視網膜中,為眼底隱結 (drusen)形成的關鍵因子。已知A2E具光敏感性,經光線照射後可誘發活性氧自由基 (reactive oxygen species, ROS)生成,據統計現代人每日使用3C裝置的時間可長達9小時,暴露於藍光的風險增加。藍光因其高強度的光化學能量及高穿透特性可穿透瞳孔直達眼底視網膜,激發A2E光氧化反應,造成視網膜上皮細胞 (retinal pigment epithelium, RPE)損傷,進而導致黃斑部病變與視力下降。本研究目的在探討A2E合併藍光照射後對RPE細胞之負面效應。首先利用silica gel-C18管柱層析及陽離子交換樹脂進行A2E化學合成,並以1H-NMR及LC-MS/MS進行A2E結構鑑定。細胞試驗則選用人類視網膜上皮細胞株ARPE-19,分別探討該細胞經(1) 不同A2E作用劑量;(2) 不同藍光照射時間,以及(3) A2E合併藍光照射等條件下,對ARPE-19細胞之影響。利用CM-H2DCFDA與MitoSOX Red染劑分別進行胞內及粒線體ROS生成之分析;以SA-β-Gal kit判斷細胞老化程度。結果顯示,A2E於生理濃度 (9 μM)下,若合併藍光照射可顯著抑制ARPE-19之細胞增生與造成細胞死亡;同時可促進胞內及粒線體ROS生成並加速細胞老化;而介入維生素E (vitamin E)可減緩上述之負面效應。此顯示藍光照射所造成之RPE細胞損傷可能與A2E誘發之氧化壓力有關。綜合上述,本研究結果有助於建構藍光-視網膜損傷之細胞實驗模式,未來可應用於篩選護眼機能性成分,亦可作為開發護眼機能性食品之參考。
A2E (N-retinylidene-N-retinylethanolamine) is a vitamin A derivative of the visual cycle which accumulated with lipofuscin and gradually deposited at the retina in the process of aging. Besides, A2E also plays a role in the formation of drusen. It is well-known that A2E is a photosensitive agent, which induced the generation of reactive oxygen species (ROS) after irradiated with light. Recently, people spend at least nine hours using electronic products, such as smartphones, tablets and computers in daily life. Blue light is one of high intensity energy, which can penetrate the pupil to the retina and induce the photooxidative reaction of A2E. Consequently, causing damage to retinal pigment epithelium cells (RPE) and impairing the vision or leading to macular degeneration. The purpose of this study is to investigate injury effects of blue light exposure in A2E-loaded human retinal pigment epithelium cells. First, we synthesize A2E by silica-C18 column chromatography, then purified A2E by cation exchange resin and identified A2E structure by 1H-NMR and LC-MS/MS. Then, we used human retinal epithelial cell line, ARPE-19, to investigate the effects of (1) different dose of A2E; (2) different irradiation time of blue light, and (3) A2E with blue light irradiation. For further analysis, we investigated the changes in physiology between different blue light exposure time points in A2E-load ARPE-19 cells. The production of intracellular ROS and mitochondrial ROS were analyzed by CM-H2DCFDA and MitoSOX Red dye respectively. Cellular senescence was detected by senescence-associated β-galactosidase staining kit (SA-β-Gal). Then results have shown that the A2E combined with blue light irradiation significantly induce cytotoxicity, intracellular ROS and mitochondrial ROS production of ARPE-19 cells. Additionally, cellular senescence increased when raised A2E concentration and prolonged blue light irradiation time. While intervention of vitamin E can alleviate the negative effects as mentioned above, showing that the damage of RPE cells caused by blue light irradiation possibly related to A2E-induced ROS. Our study contributes to establish a injury cell model of blue light in retina, which can be used to screen for effective protective components or used as a reference for the development of eye-protective functional foods in the future.

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藍光, A2E, 視網膜上皮細胞, 氧化壓力, 老化, blue light, A2E, retinal pigment epithelium cell, oxidative stress, aging

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