Chronic administration of oxytocin exerts anxiolytic and antidepressant effects in a dose-independent manner in corticosterone-induced depression model of female mice

Abstract

BackgroundOxytocin (OT) is thought to have potential as a new therapeutic strategy for depression. In spite of the fact that women are at a far greater risk for depression than are men, many experimental studies use male subjects. Thus, we investigated the anxiolytic and antidepressant effects of OT on steroid-induced depression model of female mice. Methods Adult female C57BL/6J mice were injected with OT (0.01, 0.1, or 1.0 mg/kg, i.p.) and corticosterone (CORT; 40 mg/kg, s.c.) for 4 weeks. Mice were randomly assigned to the following groups: (1) vehicle; (2) CORT; (3) OT 0.01 + CORT; (4) OT 0.1 + CORT; (5) OT 1.0 + CORT. To assess the anxiolytic and antidepressant effects of OT, mice were subjected to the open field test (OFT) and forced swimming test (FST). Results OT 0.1 + CORT group showed a significantly higher number of entries into the center zone in OFT than the CORT group. In the FST, the immobility time of the OT (0.01, 0.1, and 1.0) + CORT groups were significantly lower than that of the CORT group. The immobility time of OT (0.01 and 0.1) + CORT groups were comparable to the vehicle group. Discussion Under CORT exposure, the anxiolytic effects of OT were seen only in the middle dose of OT (0.1 mg/kg), whereas OT treatment (0.01 and 0.1 mg/kg) ameliorated the depressive behavior. Previous studies showed that OT (1.0 mg/kg) improved both the CORT-induced anxiety and depressive behaviors in males. These results suggest that the effective dose of OT may be different between sexes.