Oxidative and apoptotic effects of fluoxetine and its metabolite norfluoxetine in Daphnia magna

Abstract

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.

Binary effects of fluoxetine and zinc on the biomarker responses of the non-target model organism Daphnia magna

“…The decrease in CAT activity should mostly be attributed to the reduced SOD activity brought on by substrate limitation. Mitochondrial effects of FLX was also reported in D. magna , as evidenced by the loss of mitochondrial membrane polarization (MMP) and higher TBARS levels that signal the ROS production in our previous study (Över et al 2020 ). Although the precise mechanism of ROS formation in FLX-exposed non-target aquatic invertebrates is unknown, it may be connected to uncompensated cytosolic Ca 2+ levels and loss of MMP, while Ca 2+ -ATPase, at least in acute exposure, did not support this hypothesis.…”

“…Lower ATP levels then result in lower SERCA activity, and cytosolic Ca 2+ levels rise (Charles et al 2017 ). In our prior investigation, FLX 0.012TU and FLX 0.0015TU exposures in D. magna resulted in mitochondrial membrane depolarization after 96 h and 21 days (Över et al 2020 ). Since Ca 2+ -ATPase balances cytosolic Ca 2+ levels, induction of Ca 2+ -ATPase activity following FLX exposure is inevitable.…”

“…Following exposure to FLX 0.012TU and FLX 0.0015TU for 96-h and 21 days in D. magna in vivo, the GPX activity was increased (Över et al 2020 ). Similarly, Orozco-Hernández et al ( 2022 ) found that 96-h exposure increased lipid peroxidation levels, and SOD, CAT, and GPX activities in Danio rerio embryos at concentrations between 15 and 40 ng/L.…”

“…No alterations were observed in glutathione S -transferase (GST) activity or lipid peroxidation levels in D. magna following a 72-h exposure to 1 and 5 mg/L of FLX (Varano 2014 ). We previously demonstrated that FLX at environmental concentration (0.091 µg/L) has no prooxidant potential in D. magna after 21 days of chronic exposure (Över et al 2020 ). However, glutathione peroxidase (GPX) activity and lipid peroxidation levels increased at 10 × and 100 × of this concentration after 4 and 21 days of exposure.…”

Protective Effects of Bone Marrow Mesenchymal Stem Cells (BMMSCS) Combined with Normothermic Machine Perfusion on Liver Grafts Donated After Circulatory Death via Reducing the Ferroptosis of Hepatocytes

“…However, the storage capacity of SCS for extended-criteria donor liver is limited, which is reflected in the fact that DCD donor livers do not have sufficient physiological reserves to tolerate the functional damage during preservation and transport, which makes DCD donor livers particularly sensitive to I/R and ROS injuries [ 6 ]. During hepatic I/R injury, extracellular ROS produced by neutrophils and Kupffer cells mediate the injury [ 7 , 8 ]. Yamada et al [ 9 ] found that the high serum ferritin level of the donor was an independent risk factor for hepatic injury after liver transplantation, based on the clinical data of pediatric living donor liver transplantation.…”