Stage of Estrous Cycle Influences Behavior After Social Stress

Since women are almost twice as likely to develop major depression compared to men, research into this and other potentially debilitating mood disorders using behavioral studies should involve females despite hormonal, physiological, and potential behavior changes due to reproductive cyclicity. Until recently, most studies exclusively used males, thus limiting results of previous research to half of the population. Using adult female C57BL/6N mice as model organisms, we exposed them to novel forms of social stress across five days which encompassed the four-day estrous cycle to determine if the stages of the estrous cycle had an impact on behavior when they were exposed to social stress. Our results show that females in an earlier/pre-ovulation stage of the estrous cycle like proestrus display anti-depressive behaviors compared to mice in other stages. In contrast females in a later/post-ovulation stage like metestrus exhibit depressive behavior. Mood disorders can affect both males and females, so it is important to include females in research. However, our results suggest that use of females in behavioral studies, should consider reproductive cycling as an important variable