engleski

Exposure to α-cypermethrin during gestation does not impact de novo DNA methylation pattern in foetal rat testes

Pyrethroids are today one of the most used groups of insecticides worldwide that can act as endocrine disruptive chemicals. α-cypermethrin is a type II synthetic pyrethroid insecticide. Exposure to endocrine disruptive chemicals can lead to changes in regulation of gene expression at the epigenetic level, not entailing a change in the DNA sequence, but such effect of α- cypermethrin is still unknown. DNA methylation is one of the most studied epigenetic mechanism, being a key player in de novo silencing of retrotransposon sequences in germ cells, as well as in the establishment of sex-specific imprinting. In this study, we investigated the effect of prenatal exposure to α-cypermethrin on DNA methylation patterns in foetal testes of Wistar rats. Pregnant rat dams were treated per os from the 6th until 21st gestational day with a solution of α-cypermethrin in three doses (1, 10 and 19 mg/kg bw/day, respectively), diethylstilbestrol as positive control, corn oil as solvent control and water as negative control. The foetal rat testes were isolated on the 21st day of gestation and the methylation level of LINE-1 repetitive elements was analysed in the testicular DNA for the assessment of global methylation by bisulfite pyrosequencing. Additionally, quantitative methylation analysis was performed for Igf2 and H19 imprinted genes. We observed a lack of significant differences in average CpG methylation levels of examined DNA sequences of repetitive elements LINE-1 between the treated groups and the control. Also, we found that exposure to α-cypermethrin had no effect on the average CpG methylation levels within the differentially methylated regions (DMRs) of the Igf2 and H19 imprinted genes under these experimental conditions. It seems that prenatal α- cypermethrin exposure does not affect de novo DNA methylation process in the foetal rat testes. These results call for further researches of epigenetic changes caused by α-cypermethrin at the genome-wide level.

pyrethroid ; endocrine disruptors ; LINE-1 ; H19 ; Igf2

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