Maternal separation (MS), the daily separation from mother and littermates during the early postnatal phase, is a commonly used animal model to induce early life stress (ELS). ELS is known to induce lifelong consequences for mental and physical health, accompanied by molecular changes, like epigenetic changes leading to altered transcription of specific genes which then influence neuronal growth and brain structuring during developmental stages until adolescence and even adulthood. The altered expression of the MORC family CW-type zinc finger 1 (Morc1) gene recently has been associated with ELS and depressive symptoms in animal and human studies.
We examined the behavior of female and male rats experiencing MS in their early childhood (P2- P21) compared to control animals and a group exposed to a second stressor in late childhood (P22-P40). Animals were examined in the Elevated Plus Maze and Marble Burying test for altered anxiety-like behavior at different developmental stages (P22, P42, and P62). The results indicate different consequences of MS with altered anxiety during development after stress exposure reinforcing a positive effect of group housing during adolescence on the behavioral outcome. Moreover, a significant litter effect was found in the maternal separation group, indicating that the genes or maternal behavior might play an important role in stress coping.
The next steps will be analyzing the expression patterns of Morc1 and Interleukin 6 during the different developmental stages to test for specific windows of altered gene expression as well as potential reversal effects after undisturbed group housing.