How the Interactions in Pesticide Mixtures Affect Genotoxicity and Oxidative stress in Caiman latirostris Hatchlings.

ODETTI L. M; CHACÓN, C. F; SIROSKI, P.A; SIMONIELLO, M. F; POLETTA, G. L

Montevideo

Congreso; SETAC Latin America 15 th Biennial Meeting; 2023

SETAC

Caiman latirostris is one of the two native species of crocodilians in Argentina which area of distribution covers a wide central-northern region of the country. In the last two decades, natural distribution of this species has been strongly overlapped by agricultural frontier expansion, which has caused great loss and degradation of its habitat. In this context, caiman populations are exposed to complex mixtures of different pesticides formulations, which represent a high risk for the development of embryos and neonates. The objective of this study was to determine the genotoxic effects and oxidative stress of glyphosate (GLY), 2,4-dichlorophenoxyacetic acid (2,4-D), imidacloprid (IMI) and chlorantraniliprole (CAP) individually and in mixtures (binary and quaternary combination) in C. latirostris embryos in order to assess the potential risk of in ovoexposure that this species is suffering in their natural habitat. Under controlled condition, an embryonic exposure to these pesticides was done at concentrations recommended for soybean crops. Treatments were: negative control, GLY, 2,4-D, IMI, CAP, mixture 1 (M1): GLY+2,4-D, M2: IM I+CAP and M3: GLY + 2,4-D + IMI + CAP. At hatching, blood samples were taken for the evaluation of genotoxicity, oxidative damage to lipids and DNA, the enzymatic activity of Catalase (CAT) and Superoxide dismutase (SOD), and the expression level of their corresponding genes (catalase: cat and superoxide dismutase: sod). It has been shown that IMI, M2 and M3 induced a significant inhibition of CAT activity while no effect was observed on SOD. In turn, lipid peroxidation was significantly higher in individuals exposed to IMI, and to all the mixtures. Besides, genotoxicity and oxidative DNA damage were observed in all exposed groups. The results of mRNA expression showed no difference at transcription levels. In the same way, no alterations in growth parameters were recorded at hatching. Regarding to the mixtures, we observed a potentiating action of IMI on M3 in lipid peroxidation as well as independent action on oxidative DNA damage and genotoxicity parameters. Our results indicate that the potential environmental risks of pesticides in reptiles should receive more attention, using these early warning markers to monitor natural populations under environmental stres