Efeitos da exposição isolada e combinada de larvas de anfíbio Boana curupi ao pesticida trichlorfon e à radiação ultravioleta

Abstract

The decline in global biodiversity affects mainly the amphibian group and several factors are identified as catalysts of this process. However, it is estimated that this decline is probably due to the interaction of multiple factors. Among chemical agents, pesticides stand out. Trichlorfon (TCF), a toxic organophosphate, is widely used in crops, but its use can affect the health of non-target organisms. Another catalyst agent is ultraviolet radiation (UVR), an exogenous factor that causes genetic alterations. In view of this scenario, we analyzed the stressful effects generated by isolated and combined acute exposures to environmental doses of trichlorfon (TCF) pesticide (0.5 μg/L and 50 μg/L), and ultraviolet radiation (UVR) (184.0 kJ/m² of UVA and 3.4 kJ/m² of UVB, which correspond to 5% of the daily dose) in tadpoles of the species Boana curupi (Anura: Hylidae). In the combined treatments, we adopted three different moments of tadpole irradiation from the beginning of the acute exposure to TCF (0h, 12h, and 24h). We evaluated tadpole’ survival, change in morphological characters, cell-induced apoptosis, lipid peroxidation (LPO), protein carbonyl (PC), glutathione S-transferase (GST), non-protein thiols and acetylcholinesterase (AChE), as well as the induction of genomic DNA (gDNA) damage. UVB alone results in high mortality, as well as high level of apoptosis induction. Both UVA, UVB and TCF increase LPO, PC, and AChE, and also decrease GST activity. Regarding co-exposure, the most notable effect was observed in the interaction between UVB and TCF, which surprisingly decrease UVB-induced tadpole mortality, apoptosis, and gDNA damage. Despite these results reinforce the UVB-sensitivity of B. curupi, it indicates a complex response in face of the interaction with TCF, which may be related to activation of DNA repair pathways and/or inhibition of apoptosis decreasing UVB-induced tadpole mortality.