Ophthalmos Research and Educational Institute, Morfou 48, Egkomi, 2417 Nicosia, Cyprus.
Molecular Medicine Research Centre and Laboratory of Molecular and Medical Genetics, Department of Biological Sciences, University of Cyprus, Kallipoleos 75, 1678 Nicosia, Cyprus.
Exp Eye Res. 2018 Feb;167:128-139. doi: 10.1016/j.exer.2017.12.005. Epub 2017 Dec 16.
The purpose of this study was to evaluate the neuroprotective effects of omega-3 polyunsaturated fatty acid (ω3-PUFA) supplementation, alone or in combination with timolol eye drops, in a mouse model of hereditary glaucoma. DBA/2J mice (8.5-month-old) were assigned to an ω3-PUFAs + timolol, ω3-PUFAs only, timolol only, or an untreated group. Treated mice received a daily gavage administration of eicosapentaenoic acid (EPA) and docosahexaenoic acid and/or topical instillation of timolol (0.5%) once a day for 3 months. Blood was analysed regularly to determine ω3-PUFA levels and retinas were histologically analysed. Real-time PCR and Western blot were performed for retinal pro-inflammatory cytokines and macrophages. Blood arachidonic acid/EPA ratio gradually decreased and reached the desired therapeutic range (1-1.5) after 4 weeks of daily gavage with ω3-PUFAs in the ω3-PUFAs + timolol and ω3-PUFAs only groups. Retinal ganglion cell densities were significantly higher in the ω3-PUFAs + timolol (1303.77 ± 139.62/mm), ω3-PUFAs only (768.40 ± 52.44/mm) and timolol only (910.57 ± 57.28/mm) groups than in the untreated group (323.39 ± 95.18/mm). ω3-PUFA supplementation alone or timolol alone, significantly increased protein expression levels of M1 macrophage-secreted inducible nitric oxide synthase and M2 macrophage-secreted arginase-1 in the retina, which led to significant decreases in the expression levels of tumour necrosis factor-α (TNF-α). ω3-PUFA supplementation alone also resulted in significantly reduced expression of interleukin-18 (IL-18). ω3-PUFA + timolol treatment had no effect on the expression level of any of the aforementioned mediators in the retina. Supplementation with ω3-PUFAs has neuroprotective effect in the retinas of DBA/2J mice that is enhanced when combined with timolol eye drops. The continued inflammation following ω3-PUFAs + timolol treatment suggests that downregulation of IL-18 and TNF-α may not be the only factors involved in ω3-PUFA-mediated neuroprotection in the retina.
本研究旨在评估ω-3 多不饱和脂肪酸（ω3-PUFA）补充剂单独或联合噻吗洛尔滴眼液在遗传性青光眼小鼠模型中的神经保护作用。将 DBA/2J 小鼠（8.5 月龄）分为 ω3-PUFA+噻吗洛尔、ω3-PUFA 单独组、噻吗洛尔单独组和未治疗组。治疗组每天给予口服二十碳五烯酸（EPA）和二十二碳六烯酸，并每天局部滴注噻吗洛尔（0.5%）一次，持续 3 个月。定期检测血液中 ω3-PUFA 水平，并对视网膜进行组织学分析。用实时 PCR 和 Western blot 检测视网膜中促炎细胞因子和巨噬细胞。ω3-PUFA+噻吗洛尔组和 ω3-PUFA 单独组经 ω3-PUFA 每日灌胃 4 周后，血液花生四烯酸/EPA 比值逐渐下降并达到所需的治疗范围（1-1.5）。ω3-PUFA+噻吗洛尔组（1303.77±139.62/mm）、ω3-PUFA 单独组（768.40±52.44/mm）和噻吗洛尔单独组（910.57±57.28/mm）的视网膜神经节细胞密度明显高于未治疗组（323.39±95.18/mm）。ω3-PUFA 单独补充或噻吗洛尔单独补充均可显著增加视网膜 M1 巨噬细胞分泌诱导型一氧化氮合酶和 M2 巨噬细胞分泌精氨酸酶-1的蛋白表达水平，从而显著降低肿瘤坏死因子-α（TNF-α）的表达水平。ω3-PUFA 单独补充还导致白细胞介素-18（IL-18）的表达显著降低。ω3-PUFA+噻吗洛尔治疗对视网膜中上述任何一种介质的表达水平均无影响。ω3-PUFA 补充在 DBA/2J 小鼠的视网膜中具有神经保护作用，与噻吗洛尔滴眼液联合使用时效果增强。ω3-PUFA+噻吗洛尔治疗后的持续炎症表明，白细胞介素-18 和肿瘤坏死因子-α的下调可能不是 ω3-PUFA 介导的视网膜神经保护作用的唯一因素。
