[Protective effects of caloric restriction on ovarian function]

To study the protective effects on ovarian function by caloric restriction (CR) and its mechanism.

Thirty female C57BL/6 mice of 8 weeks old were randomly divided into two groups, including ad libitum (AL) group and caloric restriction (CR) group. The general situation and ovarian function of those mice were compared and evaluated.Ovarian follicles were counted by hematoxylin-eosin staining. Anti-Miillerian Hormone(AMH) mRNA expression of the ovary were detected by using real-time PCR. The concentrations of serum estradiol, progesterone of the mice were measured by ELISA. And the fertility of mice by mating trials were evaluated, SIRT3, Hypoxia inducible factor 1α (HIF-1α) and catalase (CAT) mRNA expression of the mice ovaries were detected by Real-Time PCR.

The total follicles were 546 in CR mice and 286 in AL mice. The proportion of primordial follicles were 38.6% (211/546) in ovaries of CR mice and 29.4% (84/286) in ovaries of AL mice, which reached statistical difference. The proportion of atretic follicles 5.3% (29/546) in ovaries of CR mice, compared with 16.8% (48/286) in AL mice, was significantly decreased (P < 0.05). The AMH mRNA expression in CR mice ovaries was 3.37 times of that of AL mice (P < 0.05). The serum concentration of estradiol in CR mice was up to (5.3 ± 1.6) pmol/L, which was much higher than (3.6 ± 1.6) pmol/L in AL mice. While, the progesterone concentration of (0.4 ± 0.3) nmol/L in CR mice was lower than (1.4 ± 0.8) nmol/L in AL mice (P < 0.05).Fertility and survival of offsprings were both improved in CR mice. The expression level of SIRT3 mRNA in CR mice ovary was 1.39 times, CAT was 1.55 times and HIF-1α was 0.31 times of those in AL mice (P < 0.05).

Caloric restriction can delay the ovary aging process through reduce follicle depletion by suppressing follicle recruitment and ovulation. The function of ovarian reserve and reproductive endocrine was effectively protected. Caloric restriction can reduce the incidence of follicular atresia, its mechanism might be associated with anti-oxidative stress.