Adıyaman University Institute of Natural and Applied Sciences, Department of Biology, Adıyaman, Turkey.
Niğde Ömer Halisdemir University Faculty of Medicine, Department of Biophysics, Niğde, Turkey.
Arh Hig Rada Toksikol. 2020 Oct 6;71(3):211-222. doi: 10.2478/aiht-2020-71-3473. Print 2020 Sep 1.
The aim of this study was to investigate the oxidative and apoptotic potential of fluoxetine, a widely used antidepressant in Turkey and the world, and of its metabolite norfluoxetine on a model non-target organism, Daphnia magna to see how exposure to this group of antidepressants (specific serotonin reuptake inhibitors) could affect the aquatic environment in which they end up. Juvenile D. magna specimens were chronically exposed to fluoxetine and norfluoxetine alone and in combination at concentrations found in the aquatic environment (0.091 and 0.011 μg/L, respectively) and to their 10-fold environmental concentrations for 21 days. Another group of 17-day-old animals were subacutely exposed to 100-fold environmental concentrations for four days. After exposure, we measured their glutathione peroxidase (GPx) and cholinesterase (ChE) activities, thiobarbituric acid-reactive substances (TBARS), and total protein content spectrophotometrically, while mitochondrial membrane potential (MMP) was analysed by fluorescence staining, and cytochrome c and ERK1/2 protein content by Western blotting. This is the first-time cytochrome c and ERK1/2 were determined at the protein level in D. magna. We also measured their carapace length, width, and caudal spine length microscopically. At environmental concentrations fluoxetine and norfluoxetine caused an increase in ChE activity and brood production. They also caused a decrease in juvenile carapace length, width, and caudal spine length and depolarised the mitochondrial membrane. At 10-fold environmental concentrations, GPx activity, lipid peroxidation levels, cytochrome c, and ERK1/2 protein levels rose. The most pronounced effect was observed in D. magna exposed to norfluoxetine. Norfluoxetine also decreased brood production. Similar effects were observed with subacute exposure to 100-fold environmental concentrations. However, total protein content decreased. All this confirms that fluoxetine and norfluoxetine have oxidative and apoptotic potential in D. magna. Daphnia spp. have a great potential to give us precious insight into the mechanisms of environmental toxicants, but there is still a long way to go before they are clarified in these organisms.
本研究旨在探讨氟西汀（一种在土耳其和世界范围内广泛使用的抗抑郁药）及其代谢产物去甲氟西汀对非靶标生物大型溞（Daphnia magna）的氧化和凋亡潜力，以了解这组抗抑郁药（特异性 5-羟色胺再摄取抑制剂）如何影响它们最终进入的水生环境。将幼年大型溞标本分别用氟西汀和去甲氟西汀单独以及联合在环境浓度（分别为 0.091 和 0.011 μg/L）下以及在其环境浓度的 10 倍下进行慢性暴露 21 天。另一组 17 天大的动物进行亚急性暴露 4 天，暴露浓度为环境浓度的 100 倍。暴露后，我们通过分光光度法测量了谷胱甘肽过氧化物酶（GPx）和胆碱酯酶（ChE）活性、硫代巴比妥酸反应物质（TBARS）和总蛋白含量，通过荧光染色分析线粒体膜电位（MMP），通过 Western blot 分析细胞色素 c 和 ERK1/2 蛋白含量。这是首次在大型溞中测定细胞色素 c 和 ERK1/2 的蛋白质水平。我们还通过显微镜测量了它们的甲壳长度、宽度和尾刺长度。在环境浓度下，氟西汀和去甲氟西汀导致 ChE 活性和繁殖增加。它们还导致幼年甲壳长度、宽度和尾刺长度减小，并使线粒体膜去极化。在环境浓度的 10 倍时，GPx 活性、脂质过氧化水平、细胞色素 c 和 ERK1/2 蛋白水平升高。在暴露于去甲氟西汀的大型溞中观察到最明显的效果。去甲氟西汀还降低了繁殖量。在亚急性暴露于环境浓度的 100 倍时观察到类似的效果。然而，总蛋白含量下降。所有这些都证实氟西汀和去甲氟西汀在大型溞中具有氧化和凋亡潜力。溞属有很大的潜力为我们提供关于环境毒物机制的宝贵见解，但在这些生物中仍有很长的路要走。
