Objective: To study the effect of aging on ovarian circadian rhythm.
Design: Human and animal study.
Setting: University hospital and research laboratory.
Patients/animals: Human granulosa cells were obtained by follicular aspiration from women undergoing in vitro fertilization (IVF), and ovarian and liver tissues were obtained from female C57BL/6 mice.
Intervention(s): None.
Main outcome measure(s): Expression of circadian genes in young and older human granulosa cells and circadian rhythm in ovaries and livers of young and older mice.
Result(s): All examined circadian clock genes in human granulosa cells showed a downward trend in expression with aging, and their mRNA expression levels were negatively correlated with age (P < 0.05). Older patients (≥ 40 years of age) had significantly reduced serum anti-Müllerian hormone (AMH) levels. Except for Rev-erbα, all other examined circadian clock genes were positively correlated with the level of AMH (P < 0.05). The circadian rhythm in the ovaries of older mice (8 months) was changed significantly relative to that in ovaries of young mice (12 weeks), although the circadian rhythm in the livers of older mice was basically consistent with that of young mice.
Conclusion(s): Lower ovarian reserve in older women is partially due to ovarian circadian dysrhythmia as a result of aging.
Keywords: Age; Circadian rhythm; Fertility; Ovary.