Effects of Exercise and Estrogen on Anxiety-like Behaviors in ‎Ovariectomized Mice

Abstract

BACKGROUND AND OBJECTIVE: Anxiety is a major symptom of menopause caused by loss of ovarian activity. Anxiety increases the intensity of vasomotor symptoms in menopausal women. This study aimed to compare the effects of exercise and estrogen on anxiety level of ovariectomized mice.  METHODS: This empirical study was conducted on 28 mice (weight: 25-35 grams) divided into four groups of seven, including ovariectomy, ovariectomy and exercise, ovariectomy and estrogen (40 mg/kg of estradiol valerate), and ovariectomy combined with exercise and estrogen. Animals were initially ovariectomized and one week later, they were placed on treadmills to run at medium intensity for 30 minutes per day. Intervention continued for five days per week, and after four weeks, anxiety was evaluated using elevated plus-maze. FINDINGS: In this study, estrogen significantly increased the percentage of open arm entry (OAE) compared to ovariectomy group (22.13±4.72 vs. 4.91±3.18, respectively) (p<0.05). In addition, combination of estrogen and exercise significantly increased open arm time (OAT) compared to ovariectomy group (46.19±6.82 vs. 4.91±3.18, respectively) (p<0.001). However, no significant difference was observed between exercise and estrogen groups. Also, exercise alone increased OAE compared to ovariectomy group (24.54±3.18 vs. 13.79± 3.23, respectively) (p<0.05). Percentage of OAE in groups of estrogen, exercise and combined exercise and estrogen was 30.61±1.25, 24.54±3.18 and 46.08±1.04, respectively, which was indicative of no significant difference. However, estrogen and combined estrogen and exercise significantly increased OAE compared to ovariectomy group (p<0.001). CONCLUSION: According to the results of this study, similar to estrogen, exercise could reduce the anxiety induced by ovariectomy in mice. 

Keywords

• Estrogen
• Exercise
• Anxiety
• Menopause