Impact of subchronic variable stress on ovariectomy and dendritic spine density in prefrontal cortex in mice.

Major depressive disorder affects both women and men but females are two times more susceptible to the incidence of depression. The majority of stress models used male rodents, whereas fewer studies included females. Volumetric reductions have been reported in brain areas critical for the stress response, such as prefrontal cortex, and remodeling of dendritic spines has been proposed as an underlying factor. The aim of this study was to determine the effects of subchronic variable stress (SCVS) in males, sham, and specifically in ovariectomized (OVX) female mice. Here, we used 6 days SCVS model to induce depressive-like behavior, and only the OVX female mice showed the depressive-like behavior, while males showed resilient type behavior. Only OVX female mice showed significant increase in dendritic spine density in SCVS paradigm. Overall, this study suggests that (1) the effects SCVS produced on the behavior of males and OVX females and (2) SCVS may induce rapid and sustained changes of PL neurons, which highlights the importance of gonadal hormones in studying depression.