Calorie restriction during gestation affects ovarian reserve in offspring in the mouse

2020 ◽  
Vol 32 (18) ◽  
pp. 1338
Author(s):  
Bianka M. Zanini ◽  
Kelvin R. S. Andrade ◽  
Jorgea Pradiee ◽  
Gabriel B. Veiga ◽  
Driele N. Garcia ◽  
...  

The aim of this study was to investigate the effect of calorie restriction (CR) during pregnancy in mice on metabolism and ovarian function in the offspring. Pregnant female mice were divided into two groups, a control group and a CR group (n=7 in each). Mice in the CR group were fed 50% of the amount consumed by control females from Day 10 of gestation until delivery. After weaning, the offspring received diet ad libitum until 3 months of age, when ovaries were collected. Ovaries were serially cut and every sixth section was used for follicle counting. Female offspring from CR dams tended to have increased bodyweight compared with offspring from control females (P=0.08). Interestingly, fewer primordial follicles (60% reduction; P=0.001), transitional follicles (P=0.0006) and total follicles (P=0.006) were observed in offspring from CR mothers. The number of primary, secondary and tertiary follicles did not differ between the groups (P>0.05). The CR offspring had fewer DNA double-strand breaks in primary follicle oocytes (P=0.03). In summary, CR during the second half of gestation decreased primordial ovarian follicle reserve in female offspring. These findings suggest that undernutrition during the second half of gestation may decrease the reproductive lifespan of female offspring.


2020 ◽  
Vol 103 (1) ◽  
pp. 24-35
Author(s):  
Rebecca A Holton ◽  
Abigail M Harris ◽  
Barenya Mukerji ◽  
Tanu Singh ◽  
Ferdusy Dia ◽  
...  

Abstract The number and quality of oocytes, as well as the decline in both of these parameters with age, determines reproductive potential in women. However, the underlying mechanisms of this diminution are incompletely understood. Previously, we identified novel roles for CHTF18 (Chromosome Transmission Fidelity Factor 18), a component of the conserved Replication Factor C-like complex, in male fertility and gametogenesis. Currently, we reveal crucial roles for CHTF18 in female meiosis and oocyte development. Chtf18−/− female mice are subfertile and have fewer offspring beginning at 6 months of age. Consistent with age-dependent subfertility, Chtf18−/− ovaries contain fewer follicles at all stages of folliculogenesis than wild type ovaries, but the decreases are more significant at 3 and 6 months of age. By 6 months of age, both primordial and growing ovarian follicle pools are markedly reduced to near depletion. Chromosomal synapsis in Chtf18−/− oocytes is complete, but meiotic recombination is impaired resulting in persistent DNA double-strand breaks, fewer crossovers, and early homolog disjunction during meiosis I. Consistent with poor oocyte quality, the majority of Chtf18−/− oocytes fail to progress to metaphase II following meiotic resumption and a significant percentage of those that do progress are aneuploid. Collectively, our findings indicate critical functions for CHTF18 in ensuring both the quantity and quality of the mammalian oocyte pool.



2005 ◽  
Vol 17 (9) ◽  
pp. 89
Author(s):  
P. S. Tanwar ◽  
J. R. McFarlane

Bone morphogenetic proteins (BMPs) were first identified on the basis of their bone inducing capacity, and later shown to be members of the transforming growth factor β (TGF β) super family. Nilsson et al.1 studied the effect of BMP-4 on follicular development in rat ovaries and found that the addition of BMP-4 to whole ovary cultures led to more numbers of developing primary follicles but less numbers of primordial follicles. Their studies indicate that BMP-4 acts as a transition factor for the conversion of primordial follicles to primary follicles. To test this hypothesis in-vivo, we conducted passive immunization studies against BMP-4 in prepubertal female mice. The mice were divided in to four groups (n = 5), and given daily SC injections of the following treatment: anti BMP-4 (50μg), PMSG (10 IU) (pregnant mare serum gonadotropin) with and without anti BMP-4 (0.5 mg/mL) and PBS for 3 days. All experimentation was approved by animal ethics committee, University of New England, Armidale, NSW. On the fourth day the mice were killed and the ovaries removed and weighed. The mice treated with anti BMP-4 had significantly smaller ovaries (4.1 ± 0.4 mg) than the control group (8.6 ± 0.9 mg). PMSG stimulated ovarian weight (21.0 ± 1.2 mg) but anti BMP-4 (23.2 ± 1.3 mg) did not significantly affect the weight of the stimulated ovaries. This data confirms BMP-4 is important in ovarian function; however, it is unclear whether this effect is on the ovary directly or via FSH. (1)Nilsson, E. E., Skinner, M.K. (2003). Bone morphogenetic protein-4 acts as an ovarian follicle survival factor and promotes primordial follicle development. Biology of Reproduction 69, 1265–1272.



2020 ◽  
Vol 26 (8) ◽  
pp. 553-566 ◽  
Author(s):  
Katarzyna J Szymanska ◽  
Xiujuan Tan ◽  
Kutluk Oktay

Abstract Among the investigated mechanisms of chemotherapy-induced damage to human primordial follicle reserve are induction of DNA double-strand breaks (DSBs) and resultant apoptotic death, stromal–microvascular damage and follicle activation. Accumulating basic and translational evidence suggests that acute exposure to gonadotoxic chemotherapeutics, such as cyclophosphamide or doxorubicin, induces DNA DSBs and triggers apoptotic death of primordial follicle oocytes within 12–24 h, resulting in the massive loss of ovarian reserve. Evidence also indicates that chemotherapeutic agents can cause microvascular and stromal damage, induce hypoxia and indirectly affect ovarian reserve. While it is possible that the acute reduction of the primordial follicle reserve by massive apoptotic losses may result in delayed activation of some primordial follicles, this is unlikely to be a predominant mechanism of loss in humans. Here, we review these mechanisms of chemotherapy-induced ovarian reserve depletion and the potential reasons for the discrepancies among the studies. Based on the current literature, we propose an integrated hypothesis that explains both the acute and delayed chemotherapy-induced loss of primordial follicle reserve in the human ovary.



2020 ◽  
Vol 64 (5) ◽  
pp. 765-777 ◽  
Author(s):  
Yixi Xu ◽  
Dongyi Xu

Abstract Deoxyribonucleic acid (DNA) is at a constant risk of damage from endogenous substances, environmental radiation, and chemical stressors. DNA double-strand breaks (DSBs) pose a significant threat to genomic integrity and cell survival. There are two major pathways for DSB repair: nonhomologous end-joining (NHEJ) and homologous recombination (HR). The extent of DNA end resection, which determines the length of the 3′ single-stranded DNA (ssDNA) overhang, is the primary factor that determines whether repair is carried out via NHEJ or HR. NHEJ, which does not require a 3′ ssDNA tail, occurs throughout the cell cycle. 53BP1 and the cofactors PTIP or RIF1-shieldin protect the broken DNA end, inhibit long-range end resection and thus promote NHEJ. In contrast, HR mainly occurs during the S/G2 phase and requires DNA end processing to create a 3′ tail that can invade a homologous region, ensuring faithful gene repair. BRCA1 and the cofactors CtIP, EXO1, BLM/DNA2, and the MRE11–RAD50–NBS1 (MRN) complex promote DNA end resection and thus HR. DNA resection is influenced by the cell cycle, the chromatin environment, and the complexity of the DNA end break. Herein, we summarize the key factors involved in repair pathway selection for DSBs and discuss recent related publications.



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