STUDY QUESTION: Does resveratrol counteract age-associated infertility in a mouse model of reproductive aging? SUMMARY ANSWER: Long-term-oral administration of resveratrol protects against the reduction of fertility with reproductive aging in mice. WHAT IS KNOWN ALREADY: Loss of oocytes and follicles and reduced oocyte quality contribute to age-associated ovarian aging and infertility. Accumulation of free radicals with age leads to DNA mutations, protein damage, telomere shortening, apoptosis and accelerated ovarian aging. Increasing evidence shows that resveratrol, enriched in certain foods, for example red grapes and wine, has anti-tumor and anti-aging effects on somatic tissues by influencing various signaling pathways, including anti-oxidation, as well as activating Sirt1 and telomerase. We investigated the potential of resveratrol to stave off ovarian aging in the inbred C57/BL6 mouse model. STUDY DESIGN, SIZE, DURATION: Young C57/BL6 females (aged 2-3 months) were fed with resveratrol added to drinking water at 30 mg/l (providing ∼7.0 mg/kg/day) for 6 or 12 months, and the fertility and ovarian functions were compared among mice treated with or without resveratrol, and young mice served as reproductive controls. Experiments were repeated three times, with an average of 25 females randomly allocated to each treatment group for each repeat. PARTICIPANTS/MATERIALS, SETTING, METHODS: Reproductive performance of female mice was determined by litter size, ovarian follicles and oocyte quantity and quality, and compared with age-matched controls. The impact of resveratrol on telomeres and telomerase activity, and expression of genes associated with cell senescence also was evaluated. MAIN RESULTS AND THE ROLE OF CHANCE: Young mice fed with resveratrol for 12 months retained the capacity to reproduce, while age-matched controls produced no pups. Consistently, mice fed with resveratrol for 12 months exhibited a larger follicle pool than controls (P < 0.05). Furthermore, telomerase activity, telomere length and age-related gene expression in ovaries of mice fed with resveratrol resembled those of young mice, but differed (P < 0.05) from those of age-matched old mice. Resveratrol improved (P < 0.05) the number and quality of oocytes, as evidenced by spindle morphology and chromosome alignment. Also, resveratrol affected embryo development in vitro in a dose-dependent manner. LIMITATIONS, REASONS FOR CAUTION: The doses of resveratrol and the experimental conditions used by different research groups have varied considerably, and the dosage influences both the effectiveness and toxicity of resveratrol. Fine-tuning the dosage of resveratrol likely will optimize its anti-aging effects on ovarian function. WIDER IMPLICATIONS OF THE FINDINGS: Our data provide a proof of principle of the fertility-sparing effect of resveratrol in female mice. Although depletion of the ovarian reserve of high-quality oocytes also contributes to increased infertility with reproductive aging in women, the data obtained using a mouse model may not extrapolate directly to human reproduction, and more extensive research is needed if any clinic trials are to be attempted. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by MOST of China National Basic Research Program (grant number: 2010CB94500 and 2012CB911200). The authors have no competing interests to declare.
STUDY QUESTION: Does resveratrol counteract age-associated infertility in a mouse model of reproductive aging? SUMMARY ANSWER: Long-term-oral administration of resveratrol protects against the reduction of fertility with reproductive aging in mice. WHAT IS KNOWN ALREADY: Loss of oocytes and follicles and reduced oocyte quality contribute to age-associated ovarian aging and infertility. Accumulation of free radicals with age leads to DNA mutations, protein damage, telomere shortening, apoptosis and accelerated ovarian aging. Increasing evidence shows that resveratrol, enriched in certain foods, for example red grapes and wine, has anti-tumor and anti-aging effects on somatic tissues by influencing various signaling pathways, including anti-oxidation, as well as activating Sirt1 and telomerase. We investigated the potential of resveratrol to stave off ovarian aging in the inbred C57/BL6 mouse model. STUDY DESIGN, SIZE, DURATION: Young C57/BL6 females (aged 2-3 months) were fed with resveratrol added to drinking water at 30 mg/l (providing ∼7.0 mg/kg/day) for 6 or 12 months, and the fertility and ovarian functions were compared among mice treated with or without resveratrol, and young mice served as reproductive controls. Experiments were repeated three times, with an average of 25 females randomly allocated to each treatment group for each repeat. PARTICIPANTS/MATERIALS, SETTING, METHODS: Reproductive performance of female mice was determined by litter size, ovarian follicles and oocyte quantity and quality, and compared with age-matched controls. The impact of resveratrol on telomeres and telomerase activity, and expression of genes associated with cell senescence also was evaluated. MAIN RESULTS AND THE ROLE OF CHANCE: Young mice fed with resveratrol for 12 months retained the capacity to reproduce, while age-matched controls produced no pups. Consistently, mice fed with resveratrol for 12 months exhibited a larger follicle pool than controls (P < 0.05). Furthermore, telomerase activity, telomere length and age-related gene expression in ovaries of mice fed with resveratrol resembled those of young mice, but differed (P < 0.05) from those of age-matched old mice. Resveratrol improved (P < 0.05) the number and quality of oocytes, as evidenced by spindle morphology and chromosome alignment. Also, resveratrol affected embryo development in vitro in a dose-dependent manner. LIMITATIONS, REASONS FOR CAUTION: The doses of resveratrol and the experimental conditions used by different research groups have varied considerably, and the dosage influences both the effectiveness and toxicity of resveratrol. Fine-tuning the dosage of resveratrol likely will optimize its anti-aging effects on ovarian function. WIDER IMPLICATIONS OF THE FINDINGS: Our data provide a proof of principle of the fertility-sparing effect of resveratrol in female mice. Although depletion of the ovarian reserve of high-quality oocytes also contributes to increased infertility with reproductive aging in women, the data obtained using a mouse model may not extrapolate directly to human reproduction, and more extensive research is needed if any clinic trials are to be attempted. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by MOST of China National Basic Research Program (grant number: 2010CB94500 and 2012CB911200). The authors have no competing interests to declare.