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OBJECTIVE: Rapamycin prolongs reproductive lifespan in mice by halting primordial follicle activation. The impact of rapamycin on the preantral follicle pool and senescence markers during ovarian aging in macaques was evaluated. MATERIALS AND METHODS: One ovary was removed from young (n=2, 6–9 yr) and old (n=2, 17–21 yr) adult female rhesus macaques during a normal menstrual cycle (pre-treatment). The remaining ovary was obtained after animals were treated with rapamycin (bid, IM, 0.02mg/kg) for 10 months. Ovaries were fixed and serially sectioned for follicle counting (each 10th section, 15-39 sections/ovary). Immunohistochemical analyses were performed for anti-Mullerian hormone (AMH) and cellular senescence markers p16, p53, and p21 (1 slide/ovary). Qualitative comparisons were made due to the small sample size. RESULTS: The primordial follicle pool was decreased in young (3,939 pre-treatment vs. 2,219 post-treatment), but similar in old (555 pre- vs. 574 post-treatment) females after rapamycin. The number of transitional primordial follicles was greater before rapamycin than after in both young (14,920 vs. 4,924) and old (1,915 vs. 1,311) females. The number of primary follicles before (2,617) rapamycin was greater than after (560) in young and old females (518 pre- vs. 428 post-treatment). A similar proportion of follicles positive for p16 was seen before and after rapamycin in both young and old females. Similar findings were also observed for AMH, except there are fewer positive follicles in the rapamycin-treated older group. The proportion of follicles staining positive for both p53 and p21 was increased in both young and old monkeys after treatment. CONCLUSIONS: Rapamycin had no impact on the primordial and primary follicle pools in old female macaques while unexpectedly decreasing both pools in young females. While the number of p16-positive follicles was unaffected by rapamycin treatment, the number of p53 and p21-positive follicles was increased by treatment in both age cohorts. IMPACT STATEMENT: At the dose and treatment interval used, rapamycin does not appear to suppress follicular activation and has mixed effects on senescence markers in aging nonhuman primate ovaries.
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The Immp2l Mutation Causes Ovarian Aging Through ROS-Wnt/β-Catenin-Estrogen Pathway: Preventive Effect of Melatonin
Abstract Mitochondria play important roles in ovarian follicle development. Mitochondrial dysfunction, including mitochondrial gene deficiency, impairs ovarian development. Here, we explored the role and mechanism of mitochondrial inner membrane gene Immp2l in ovarian follicle growth and development. Our results revealed that female Immp2l-/- mice were infertile, whereas Immp2l+/- mice were normal. Body and ovarian weights were reduced in the female Immp2l-/- mice, ovarian follicle growth and development were stunted in the secondary follicle stage. Although a few ovarian follicles were ovulated, the oocytes were not fertilized because of mitochondrial dysfunction. Increased oxidative stress, decreased estrogen levels, and altered genes expression of Wnt/β-catenin and steroid hormone synthesis pathways were observed in 28-day-old Immp2l-/- mice. The Immp2l mutation accelerated ovarian aging process, as no ovarian follicles were detected by age 5 months in Immp2l-/- mice. All the aforementioned changes in the Immp2l-/- mice were reversed by administration of antioxidant melatonin to the Immp2l-/- mice. Furthermore, our in vitro study using Immp2l knockdown granulosa cells confirmed that the Immp2l downregulation induced granulosa cell aging by enhancing reactive oxygen species (ROS) levels, suppressing Wnt16, increasing β-catenin, and decreasing steroid hormone synthesis gene cyp19a1 and estrogen levels, accompanied by an increase in the aging phenotype of granulosa cells. Melatonin treatment delayed granulosa cell aging progression. Taken together, Immp2l causes ovarian aging through the ROS-Wnt/β-catenin-estrogen (cyp19a1) pathway, which can be reversed by melatonin treatment.
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- Award ID(s):
- 1827833
- PAR ID:
- 10314402
- Date Published:
- Journal Name:
- Endocrinology
- Volume:
- 161
- Issue:
- 9
- ISSN:
- 0013-7227
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1210/endocr/bqaa119
