EN
Prenatal developmental period is a critical window, where any perturbation of embryonic/fetal environment can lead to behavioural abnormalities and diseases in adult life, such as depression and stress disorders. The mechanisms underlying long term effects, induced by early perturbation, are not well described, but an epigenetic origin has been suggested. In this work we wanted to investigate whether and how blastomere biopsy on 8-cells stage embryos can have long-term effects on behaviour. One-month-old mice derived from the biopsed embryos were subjected to a battery of behavioural tests. The animals displayed an increased locomotor and exploration activity (p<0.05) and increased anxiety-like behaviour. Interestingly, the depression-like behaviour in the tail suspension test was observed only in female offspring (p<0.001). In addition, to investigate the epigenetic mechanism underlying these behavioural alterations, we analyzed expression of imprinted genes Snrpn, Peg1 and Ube3a in blastocysts obtained after biopsy. These imprinted genes are highly expressed in preimplantation embryos, where their epigenetic programming is defined, and in brain, shaping the behavioural phenotype of offspring. Real-Time PCR analysis revealed significant down-regulation of Peg1 (p<0.05), Snrpn and Ube3a (p<0.01) in blastocysts derived from the biopsed embryos, compared to controls. The results suggest that blastomere biopsy causes an altered expression of imprinted genes in preimplantation embryo. The reduction of expression of these transcripts can cause anxiety- or depression-like behaviours and alteration of locomotory activity in offspring obtained following biopsy of early embryos.