Can paracetamol alter the reproduction regulatory axis of a male Neotropical catfish? A multibiomarker approach

Abstract Paracetamol (PCM), or acetaminophen, is one of the most used drugs for human treatment and has been found contaminating the aquatic environment. Besides, it can affect the aquatic biota. The aim of this study was to investigate the effects of PCM in the male catfish Rhamdia quelen reproductive axis after 14 days of exposure. Different biomarkers were evaluated in hypothalamus, liver and gonads, as well as sexual hormone levels. The fish were exposed to solvent (acetone 0.0003%; control group) and to three PCM concentrations: 0.25, 2.5 and 25 µg.L -1 , based on environmental concentrations. After the exposure period, they were anesthetized for blood sampling and biometrics and euthanized for tissues collection. From blood, it was obtained plasma for 11 – keto testosterone and 17β – estradiol hormones quantification. The hypothalamus was collected for brain aromatase ( cyp19a1b ) gene expression; the liver for the vitellogenin ( vtg ) gene expression and biochemical biomarkers; and gonad for the biochemical and histological biomarkers analyses. No alterations were observed in the hormones levels, sexual maturation or in cyp19a1b and vtg gene expression. In the liver, the non-protein thiols concentration and the superoxide dismutase (SOD) activity were altered. In gonads, glutathione S -transferase (GST), SOD and glutathione peroxidase (GPx) activities changed. The results showed that PCM environmental concentrations can cause alterations in the antioxidant system, mainly in the R. quelen male gonads under the tested conditions. However, no significant changes of hormones levels or the expression of genes related to the reproduction axis were observed.