Social Behaviour and Epigenetic Status in Adolescent and Adult Rats: The Contribution of Early-Life Stressful Social Experience
Early-life experiences have been linked to individual’s epigenetic status and social behaviour. Therefore, the present study aims to test whether the presence of mother suppress the early-life stressful social experience (SSE)-induced effect on social behaviour of adolescent and adult rats, and associated epigenetic changes. To test this, experimental groups [maternally separated pups (MSP)/pups with their mother (M+P)] were allowed to experience the presence of a stranger (ST), and then their social behaviour was compared with the maternal separated (MS) and control (Con) group. We observed that MS, MSP-ST group showed less social interaction with the unknown conspecifics than known conspecifics compared to other groups. Subsequently, we found that SSE elevated the level of DNA methyltransferases (Dnmt3a), ten-eleven translocation (Tet3), methyl-CpG-binding protein-2 (MeCP2) and Repressor Element-1 Silencing Transcription Factor (REST) in amygdala of adolescent and adult MS, MSP-ST groups compared to other groups. As expected, SSE altered the histone (H3) lysine (K14/K9) acetylation (ac) and H3K4/K9 methylation (me2/me3). SSE decreased the level of H3K14ac and H3K9ac in adolescents and then increased in adults. Interestingly, H3K4me2/me3 levels were elevated in adolescent and adults. Whereas H3K9me2/me3 shows contrasting pattern in adolescent, but H3K9me2/me3 levels were increased in adults. In addition, the expression of brain-derived neurotrophic factor (BDNF) was reduced in MS, MSP-ST groups’ adolescent and adult rats. Observed correlation between epigenetic changes and social behaviour possibly contributed by early-life SSE in the absence of mother, but mother’s presence suppresses the effect of early-life SSE.
KeywordsEarly-life stress Social behaviour Amygdala Epigenetics Histone methylation Histone acetylation
CK is recipient of University Research Fellowship from BDU. KER thank Department of Science and Technology for providing financial support through major project (EMR/2016/005217 Dated: 21.03.2018). Department of Animal Science supported by DST-PURSE, UGC-SAP-DRS-II and DST-FIST.
Compliance with Ethical Standards
Conflict of interest
The authors declare that they have no conflict of Interest.
All procedures performed in studies involving animals were in accordance with the ethical standards of the institution or practice at which the studies were conducted.
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