Investigation of apoptotic and pro-oxidative effects of fluoxetine and norfluoxetine on Daphnia magna

The aim of the present study is to investigate the pro-oxidative and pro-apoptotic potential of fluoxetine, a widely used antidepressant in Turkey and world, and its metabolite norfluoxetine on a model organism, Daphnia magna. Juvenil D. magna specimens were exposed to environmentally-related, and their 10 fold concentrations of fluoxetine, norfluoxetine, and their mixtures for 21 days. 17 days old D. magna specimens were also exposed to 100 fold of environmentally related concentrations of these toxicants and their mixtures for 4 days. After the exposure periods, GPx and tChE enzyme activities, TBARS, and total protein contents were analysed spectrophotometrically, mitochondrial membrane potential was analysed fluorescence staining, cytochrome c and ERK1/2 protein contents were analysed by Western blotting, and carapace length, maximum carapace width, caudal spine length were analysed microscopically. At the environmentally-related concentrations, fluoxetine and norfluoxetine caused an increase in tChE enzyme activity and parturition rate; however, a decrease in juvenile carapace length, maximum carapace width, and caudal spine length. MMP depolarization also occurred. At the 10 fold of environmentally-related concentrations, GPx activity and lipid peroxidation levels, cytochrome c and ERK1/2 protein contents were increased. The most pronounced effect was observed in norfluoxetine-exposed D. magna. Norfluoxetine decreased the parturition rate. The similar was also observed in the subacute exposure; moreover, total protein contents decreased. Consequently, fluoxetine and norfluoxetine have pro-oxidative and pro-apoptotic potential in D. magna. Daphnia spp. have a potential to introduce precious mechanistic knowledge.