Subchronic stress-induced depressive behavior in ovariectomized mice

• Published in: Life sciences (1973) Vol. 84; no. 15; pp. 512 - 516
• Main Authors: Nakagawasai, Osamu, Oba, Akira, Sato, Atsushi, Arai, Yuichiro, Mitazaki, Satoru, Onogi, Hiroshi, Wakui, Kenji, Niijima, Fukie, Tan-No, Koichi, Tadano, Takeshi
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 10.04.2009
• Subjects: Animals; Avoidance Learning - physiology; Behavior, Animal - physiology; Chronic Disease; Depression; Depression - etiology; Depression - metabolism; Depression - physiopathology; Depression - prevention & control; Disease Models, Animal; Estradiol; Estradiol - metabolism; Estradiol - therapeutic use; Female; Forced swimming test; Maze Learning - physiology; Mice; Mice, Inbred Strains; Motor Activity - physiology; Ovariectomy; Stress; Stress, Psychological - complications; Stress, Psychological - metabolism; Stress, Psychological - physiopathology; Swimming - physiology; Forced swimming test; Depression; Ovariectomy; Estradiol; Stress
• DOI: 10.1016/j.lfs.2009.01.009
• ISSN: 0024-3205

Mood disorders including depression are more common in women than men, particularly in times of lower estradiol levels. In this study, we investigated the effect of estrogen on emotional behavior in mice in a stress environment. Female mice were divided into four groups: two groups were ovariectomized (OVX) and two were sham-operated. One group each of OVX and sham mice was kept in a normal environment and the other groups were assigned to a daily stress (1 h/day) for 7 days from 5 days after operation. On the 14th day after operation, subjects were measured to assess behavioral specificity, locomotor activity, elevated plus-maze (EPM) behavior, passive avoidance (PA) behavior and forced swimming behavior. The OVX plus stress (OVX + S) group showed a significant prolongation of immobility compared with the other groups. In all the groups there were no changes in locomotor activity, EPM behavior or PA behavior. We further examined the effect of estrogen against depressive behavior in the OVX + S group. The vehicle or 17β-estradiol (E2) was administered s.c. to OVX + S mice for 4 days beginning on post-operative day 11. Subchronic E2 treatment decreased the stress response and improved depressive behavior relative to the vehicle group. These data have important implications regarding the prevention of depression in postmenopausal women undergoing estrogen therapy.