RESUMO
Fluoxetine (FLX), a selective serotonin reuptake inhibitor, is widespread in aquatic environments. Despite its reported effects on behavior and reproduction in aquatic species, little is known about the effects of FLX on cellular detoxification and defense system in bivalves. Here, the adult Asian clam (Corbicula fluminea) was exposed to 0.5, 5, and 50 µg L(-1) FLX for 30 d. Siphoning behavior was inhibited by treatment with 50 µg L(-1) FLX. Additionally, superoxide dismutase (SOD) activity in the gills and digestive glands significantly decreased (p<0.05) with 5 and 50 µg L(-1) FLX treatments, whereas catalase (CAT) activity and malondialdehyde (MDA) content markedly increased (p<0.05). Moreover, transcription of thioredoxin reductase (TR), glutathione peroxidase (GPx) and Glutathione S-transferase pi class (GSTpi) was significantly upregulated (p<0.05), whereas glutathione reductase (GR) was markedly downregulated (p<0.05). These findings suggest that FLX affects behavior and induces oxidative stress in C. fluminea. The downregulation of ATP-binding cassette (ABC) transportor genes (ABCB1, ABCC1 and ABCG2) transporter genes indicated that FLX might suppress the multixenobiotic resistance (MXR) system in C. fluminea. Our results provide new insights into the adverse effects of FLX on the cellular detoxification and MXR system of C. fluminea.
Assuntos
Comportamento Animal/efeitos dos fármacos , Corbicula/efeitos dos fármacos , Fluoxetina/toxicidade , Poluentes Químicos da Água/toxicidade , Análise de Variância , Animais , Antioxidantes/metabolismo , Catalase/metabolismo , China , Corbicula/genética , Primers do DNA/genética , DNA Complementar/genética , Relação Dose-Resposta a Droga , Fluoxetina/metabolismo , Brânquias/metabolismo , Glutationa Peroxidase/metabolismo , Glutationa Redutase/metabolismo , Malondialdeído/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Reação em Cadeia da Polimerase em Tempo Real , Superóxido Dismutase/metabolismo , Tiorredoxina Dissulfeto Redutase/metabolismo , Poluentes Químicos da Água/análiseRESUMO
Uranium (U) internal distribution and involved effects in the bivalve Corbicula fluminea have been studied after direct chronic exposure (90 d, 10 µg.L-1). U distribution was assessed at the subcellular level (Metal Rich Granules -MRG-, pellets and cytosol fractions) in two main organs of the bivalve (gills and visceral mass). Micro-localisation was investigated by TEM-EDX analysis in the gills epithelium. DNA damage in gill and hemolymph samples was measured by the Comet assay. The 90-d exposure period led to a significant increase of U concentration in gills over time (× 5) and a large U quantity in subcellular granules in gills. Finally, a significant increase (× 2) in DNA damage was noted in exposed gills and haemocytes. This study shows that the accumulation levels and consequently the potential toxicity cannot be successfully predicted only on the basis of concentration in water or in tissues and subcellular fractions after chronic exposure.