ABSTRACT
Objective To explore whether synergistic action occurs in development of depression-like behaviors using ovariectomy combined bondage stress,and whether hippocampal neural progenitor state is changed following depression-like behaviors in mice.Methods Forty female C57B/L mice were divided into four groups randomly,which included ovariectomy,bondage stress,ovariectomy combined bondage stress and sham groups.Depression-like behaviors were evaluated by open field test,sucrose preference and forced swimming test after animals had been treated for 21 days.All animals were fixed by 4％ PA perfusion through left ventricle,then brain was removed,and coronal serials sections were made.Expression of Ki67 and DCX was tested by immunohistochemistry or immunofluorescence in subgranular zone of hippocampal dentate gyrus (SGZ).Results Body weight((18.70± 0.25) g vs (20.96±0.24)g),novelty-seeking behavior and sucrose preference decreased in ovariectomy combined bondage stress-group compared with those in sham group (P＜0.05),but forced swimming time increased in shame group((165.6±9.6)s vs (140.28±12.3) s).Likewisely,Ki67-positive cells((8.6±2.4)/section) and DCX-positive cells((4.2±1.4)/section) in SGZ decreased in ovariectomy combined bondage stress-group compared with those in sham group(Ki67:(16.7±2.5/section),DCX:(12.6±2.3/section) (P＜0.05).Unsimilarly,depressionlike behaviors had little change in ovariectomy-or bondage stress-groups compared with those in sham-group.Conclusion Ovariectomy combined bondage stress has synergistic action in development of depression,and inhibits the active state of progenitor in SGZ in mice.