Gene Expression Profiles as Potential Biomarkers in Caiman latirostris Hatchlings Exposed to Pesticides

STRINGHINI BOLAÑO B; COLMAN LARÓVERE C; ODETTI L. M; POLETTA, GISELA L.

Montevideo

Congreso; SETAC Latin America 15 th Biennial Meeting; 2023

SETAC

For several years, caiman populations have been facing one of the main problems affecting many wild species: habitat loss as a consequence of land being used for agricultural, and potential exposure to pesticides used in such settings. Alterations in mRNA patterns could offer new insights into the role of genes in the context of toxicity. In this sense, the altered gene expression could be used to detect biological toxicity and/or to monitor the impact of different xenobiotics in natural environments. Therefore, this study investigates the toxicity of pesticides in blood ofCaiman latirostris hatchlings by using a particular set of genes involved in detoxification pathways, DNA damage repair and cell cycle regulation [i.e. p450, gst, parp1, p53, bax and bcl2].Pesticides concentrations employed were equivalent to those recommended in agricultural practices for application in soybean crops: glyphosate (GLY -2 %), 2,4-dichlorophenoxyacetic acid (2,4- D – 0.12 %) and the binary mixture (M: GLY+2,4-D). The applications were made on the nest material in contact with the eggs at the beginning of the incubation period. After hatching, total RNA was isolated from blood of all caiman and expression levels analyzed through PCR. The mRNAs levels were visualized in agarose gel and registered using a digital camera. Bands intensity of each row, internal control and target gene, were quantified by ImageJ software and intensity ratios were calculated. The results showed downregulation in the expression of p53 and baxgenes in GLY and M compared to the controls. In turn, an overexpression was found in bcl2, p450and gst in GLY as well as in bcl2 in animals exposed to the M. This study proved that the use of pesticide formulations at low concentrations generates modifications in expression pattern of genes encoding proteins that participate in detoxification pathways, DNA damage repair and cell cycle regulation in this species. Overall, the present study is the first to investigate these genes as potential biomarkers and their related biological pathways under pesticide exposure, in blood of the broad snouted caiman. Overall, the results from this work suggest the potential application of the expression profiling of these genes for the biological monitoring of pesticide exposure in caimans