Number Of Primordial Follicles Research Articles

PARP1-catalyzed PARylation of YY1 mediates endoplasmic reticulum stress in granulosa cells to determine primordial follicle activation

Although only a small number of primordial follicles are known to be selectively activated during female reproductive cycles, the mechanisms that trigger this recruitment remain largely uncharacterized. Misregulated activation of primordial follicles may lead to the exhaustion of the non-renewable pool of primordial follicles, resulting in premature ovarian insufficiency. Here, we found that poly(ADP-ribose) polymerase 1 (PARP1) enzymatic activity in the surrounding granulosa cells (GCs) in follicles determines the subpopulation of the dormant primordial follicles to be awakened. Conversely, specifically inhibiting PARP1 in oocytes in an in vitro mouse follicle reconstitution model does not affect primordial follicle activation. Further analysis revealed that PARP1-catalyzed transcription factor YY1 PARylation at Y185 residue facilitates YY1 occupancy at Grp78 promoter, a key molecular chaperone of endoplasmic reticulum stress (ERS), and promotes Grp78 transcription in GCs, which is required for GCs maintaining proper ERS during primordial follicle activation. Inhibiting PARP1 prevents the loss of primordial follicle pool by attenuating the excessive ERS in GCs under fetal bisphenol A exposure. Together, we demonstrate that PARP1 in GCs acts as a pivotal modulator to determine the fate of the primordial follicles and may represent a novel therapeutic target for the retention of primordial follicle pool in females.

The effects of human amnion membrane-derived mesenchymal stem cells conditioned medium on ionizing radiation-induced premature ovarian failure and endoplasmic reticulum stress-related apoptosis mechanism

ObjectivesPremature ovarian failure (POF) is defined as the cessation of menstrual periods for at least 4–6 months before the age of 40 years, accompanied by FSH values measuring over 40 IU/L for a month. Radiation therapy, one of the cancer treatment methods, is known to accelerate ovarian aging by reducing and eliminating the number of primordial follicles in the ovarian follicle pool. Ionizing radiation has been reported to cause POF. The objective of this study is to investigate the impact of mesenchymal stem cell conditioned medium (hAMSCs-CM), which is isolated from the amniotic membrane of human placenta, on premature ovarian failure (POF) caused by whole-body irradiation. The study will focus on the ER stress and apoptosis mechanisms in the process. Study DisaynA POF model was created by exposing rats to 7 Gy of whole-body irradiation. Serum-free hAMSCs-CM were then administered via the tail vein. Follicle count was performed on the ovaries, and immunohistochemistry was used to determine the expressions of GRP78, CHOP, IRE-1, caspase-12, caspase-9, caspase-3. TUNEL was also carried out, and levels of serum FSH, LH, E2, AMH, and oxidative stress marker 8-OHdG were measured. Results and ConclusionThe application of hAMSCs-CM has been found to have a positive impact on follicles affected by radiation. After treatment, the number of primordial, primary, secondary, and graafian follicles, which had previously decreased due to radiation, showed an increase. Furthermore, the number of atretic follicles, which had been increasing due to radiation, showed a decrease. ER is one of the targets affected by ionizing radiation. After ionizing radiation, the expressions of ER stress-related markers and apoptosis markers increased in the ovary. After hAMSCs-CM administration, the expressions of these markers and number of TUNEL-positive cells decreased. Following irradiation, anti-mullerian hormone (AMH) and estradiol (E2) levels decreased, while follicle stimulating hormone (FSH) and luteinizing hormone (LH) levels increased. After administration of hAMSCs-CM, AMH and E2 levels increased, while FSH and LH levels decreased.Amnion membrane-derived mesenchymal stem cell conditioned medium can play a therapeutic role in ionizing radiation-induced premature ovarian failure by reducing endoplasmic reticulum stress and apoptosis.

Effect of direct therapeutic ultrasound exposure of ovaries on histopathology, inflammatory response, and oxidative stress in dogs

BackgroundThis research was designed to evaluate the effects of therapeutic ultrasound waves on ovarian germinal tissue and inflammatory cytokines (interleukin-6 (IL-6), IL1β, tumor necrosis factor-α (TNF-α)), acute phase proteins (serum amyloid A (SAA), C reactive protein (CRP)) and oxidative stress (total antioxidant capacity (TAC), and malondialdehyde (MDA)) in dogs. Twenty-six clinically healthy adult mix-breed female dogs were aligned into three groups. Laparotomy was performed in control (n = 6) and treatment (T5, n = 10; T10, n = 10) groups. The ultrasonic exposure of ovaries in treatment groups was performed during laparotomy by round motions of the therapeutic ultrasonic transducer on both ovaries (1 MHz frequency, 1.5 W⁄cm2) for 5 min in the T5 group and for 10 min in the T10 group. Blood samples were collected from the jugular vein into a plain glass tube on days 0 (before laparotomy), 3, 6, and 9 after surgery. All control and treatment groups’ dogs were ovariectomized for histological evaluation on day 60 after laparotomy or laparotomy + ultrasound exposure.ResultsDirect exposure of ovaries with therapeutic ultrasound waves induced inflammation and oxidative stress comparison with the control group. Histopathological evaluation of treated ovaries with ultrasound waves indicated a decreased number of primordial follicles (ovarian reserve) and oocyte preservation scores compared with ovaries in the control group.ConclusionsThese changes may cause subfertility in the long term. It seems that inflammatory response and oxidative stress are factors in the permanent damage of ovarian tissue.

Ovarian Histology of Removed Ovaries After Gender-Affirming Testosterone Therapy.

Introduction. Assigned female at birth transgender people go through a gender-affirming hormone therapy using testosterone. We aimed to define the histological changes in the removed ovaries of these patients and investigate the correlation of these changes to factors like chronological age and duration of hormone therapy. Methods. The ovaries of 84 patients who had at least 6 months of testosterone therapy before surgery were examined. Tunica albuginea thickness, cortical thickness, and number of different stages of follicles were recorded. Results. The mean age was 27.2 ± 4.9 years. Testosterone duration 25.8 ± 13.1 months. The mean tunica albuginea thickness was 356.4 ± 152.6 µm. The mean cortical thickness was 799.6 ± 245.6 µm. The number of primordial (C1) follicles was 18.03 ± 13.6 and antral (C3) follicles was 3.1 ± 1.9 per cm². When grouped as using therapy under or over 2 years the groups did not have differences in histological findings. Hormone duration did not correlate with histological findings except for a positive correlation with atretic follicle number. However, age was negatively correlated with number of follicles at all stages except atretic follicles and positively correlated with cortical thickness (P < .05). Conclusion. Testosterone therapy induces multifollicularity, stromal hyperplasia, and luteinization in some patients. Hormone duration did not correlate with ovarian histology whereas chronological age did suggesting an effect of age on ovarian reserve rather than duration of hormone therapy.

Prenatal and postnatal exposure to polychlorinated biphenyls alter follicle numbers, gene expression, and a proliferation marker in the rat ovary

Polychlorinated biphenyls (PCBs) were used in industrial applications until they were banned in the 1970s, but they still persist in the environment. Little is known about the long-term effects of exposure to PCB mixtures on the rat ovary during critical developmental periods. Thus, this study tested whether prenatal and postnatal exposures to PCBs affect follicle numbers and gene expression in the ovaries of F1 offspring. Sprague-Dawley rats were treated with vehicle or Aroclor 1221 (A1221) at 1 mg/kg/day during embryonic days 8–18 and/or postnatal days (PND) 1–21. Ovaries from F1 rats were collected for assessment of follicle numbers and differential expression of estrogen receptor 1 (Esr1), estrogen receptor 2 (Esr2), androgen receptor (Ar), progesterone receptor (Pgr), and Ki-67 (Ki67) at PNDs 8, 32, and 60. Sera were collected for measurement of estradiol concentrations. Prenatal exposure to A1221 significantly decreased the number of primordial follicles and the total number of follicles at PND 32 compared to control. Postnatal PCB exposure borderline increased Ki67 gene expression and significantly increased Ki67 protein levels (PND 60) compared to control. Combined prenatal and postnatal PCB exposure borderline decreased Ar expression (PND 8) compared to control. However, PCB exposure did not significantly affect the expression of Pgr, Esr1, and Esr2 or serum estradiol concentrations compared to control at any time point. In conclusion, these data suggest that PCB exposure affects follicle numbers and levels of the proliferation marker Ki67, but it does not affect expression of some sex steroid hormone receptors in the rat ovary.

Altered m6A modification is involved YAP-mediated apoptosis response in 4-vinylcyclohexene diepoxide induced ovotoxicity

4-Vinylcyclohexene diepoxide (VCD), an industrial occupational health hazard chemical associated with premature ovarian insufficiency (POI) and reproductive failure. Recently, investigators have paid an increasing attention on VCD model of menopause recapitulates the natural, physiological transition through perimenopause to menopause. The current study sought to examining the mechanisms of follicular loss and exploring the effect of the model on systems outside of the ovaries. In this study, 28 days female SD rats were injected with VCD (160 mg/kg) vehicle for 15 consecutive days, euthanized in the diestrus phase approximately 100 days after the onset of treatment. Reproductive system injury, Neuroendocrine, sex hormone levels and receptor were observed, the levels of N6-methyladenosine (m6A) RNA modification and the expression of modulator genes were first measured. The VCD treated rats showing irregular estrous cycles, significantly reduced in the number of primordial follicles, the preantral and antral follicles also decreased significantly, accompanied by the plasma level of FSH increased and anti-Mullerian hormone (AMH) were decreased. The total m6A level was significantly decreased after exposure to VCD. Moreover, ALKBH5-mediated YAP m6A modification changed in VCD - induced premature ovarian insufficiency. These present work provides a new perspective on m6A modification in the VCD-induced POI rat model, which could provide valuable insights into the mechanisms underlying follicle development and finding new therapeutic targets for follicle prematurely exhausted. Also provide novel methodological guidance and endocrine basis to guide research and extend the applications in premature ovarian insufficiency model.

P-395 Protective effect of metformin on the ovarian reserve of prepubertal mice under cyclophosphamide chemotherapy

Abstract Study question Can metformin reduce the side effects of cyclophosphamide on the ovaries of prepubertal mice treated with cyclophosphamide? Summary answer Yes, metformin, as an inhibitor of mTOR and, by affecting the HIPPO pathway, can exert its protective effect in the chemotherapy mice model. What is known already PI3K/AKT and HIPPO pathways are influential pathways in the process of activation of primordial follicles and proliferation of cell growth, which are affected by various agents and drugs such as cyclophosphamide. One of the side effects of cyclophosphamide is the reduction of the ovarian reserve through abnormal changes in the PI3K/AKT and HIPPO pathways. Metformin is a drug that is used to treat type 2 diabetes and at the same time regulates PI3K/AKT and HIPPO pathways and prohibits the proliferation of cancer cells. Study design, size, duration Controlled experimental study. After metformin and cyclophosphamide dose adjustment, 12 female NMRI 14-day-old mice were randomly divided into four groups: the control group (CONT), metformin group (MET), cyclophosphamide group (CYC) and metformin with cyclophosphamide group (MET-CYC). Participants/materials, setting, methods Mice were treated by intraperitoneal injection of a dose of 150mg/kg of metformin for 11 consecutive days, and/or a dose of 65mg/kg of cyclophosphamide every three days (The third, sixth and ninth days). The mice were sacrificed 24 hours after the last metformin injection or 3 days after the last cyclophosphamide injection. The ovaries were collected for stereological evaluation, and expression of Pten, Mtor, Yap-1, p53, Bcl-2, and Bax genes by qRT-PCR method. Main results and the role of chance The stereological evaluation showed that the ovarian volume and primordial follicle number in the CYC group were decreased compared to the other groups (P &amp;lt; 0.05), and also in the MET-CYC group reduced compared to the CONT and MET groups, but increased significantly compared to the CYC group (P &amp;lt; 0.05). A significantly increased number of growing follicles was observed in the CYC group compared to the other groups (P &amp;lt; 0.05). The molecular analysis showed that the Pten expression in the CYC group was lower than CONT and MET groups (P &amp;lt; 0.05). Mtor expression in the CYC group was significantly increased compared to other groups (P &amp;lt; 0.05). The expression of Yap-1 was significantly decreased in the MET group compared to other groups (P &amp;lt; 0.05), and was lower in the MET-CYC than in the CYC group (P &amp;lt; 0.05). The of P53 expression in the MET-CYC group was higher than CONT and MET groups (P &amp;lt; 0.05), and was increased in the CYC compared to the CONT group (P &amp;lt; 0.05). Bcl-2 expression was higher in CONT and MET groups than in MET-CYC and CYC groups (P &amp;lt; 0.05). The expression of Bax in the CYC group was significantly increased compared to CONT and MET groups (P &amp;lt; 0.05). Limitations, reasons for caution Due to ethical issues in less use of mice, dose of metformin was obtained according to the articles used in adult mice and also by using the human to animal dose conversion formula. Wider implications of the findings It can be concluded that metformin during cyclophosphamide treatment can maintains ovarian volume, reserve, and activity in prepubertal mice by regulating PI3K/AKT and HIPPO pathways. Considering the relatively acceptable cost and long-term safety of metformin, it is a promising factor to be used to preserve fertility during chemotherapy. Trial registration number not applicable

O-244 Mitochondrial fission factor (MFF) is required for female fertility and oocyte development

Abstract Study question To explore the role of Mitochondrial fission factor (MFF) in female fertility and oocyte development using a Mff knockout mouse model. Summary answer Mff deficiency influences mitochondrial dynamics in oocytes at germinal vesicle stage (GV), and results in premature ovarian failure (POF) and female infertility. What is known already Mff regulates mitochondrial quality control (MQC) by influencing mitochondrial dynamics. MQC has critical effects on oocyte development and POF. However, little is known about the role of Mff in oocyte development and female fertility. Study design, size, duration The Mff knockout (Mff-/-) mice were generated via the CRISPR-Cas9 system. Adult Mff-/- female mice were compared to wildtype (WT) female mice. Female mice at 2-month old from each group (Mff-/- or WT, n = 5) were used to assess the fecundity for 10 months. The follicle development (n = 4 mice), the number of GV oocytes (n = 5 mice) and metaphase II (MII) oocytes (n = 5 mice) were determined. Participants/materials, setting, methods Female mice from each group were mated with adult WT males to assess the fecundity. Follicle development was evaluated in ovaries after fixation, paraffin embedding, and sectioning, followed by hematoxylin and eosin staining. MFF and DRP1 protein expression was evaluated by western blot. Oocyte mitochondria were stained with the Mito-Tracker Red CMXRos. Main results and the role of chance The Mff deficient ovaries had significantly lower levels of MFF (0.056 vs. 1, p &amp;lt; 0.01) than the WT ovaries. Mff-/- female mice were infertile (0 vs. 39, p &amp;lt; 0.05). Mature (8-week-old) Mff deficient ovaries had significantly lower weight (0.0043 vs. 0.011, p &amp;lt; 0.05) compared to the WT. The 2-month-old female Mff-/- mice had a lower number of primordial (220 vs. 775, p&amp;lt; 0.05), primary (128 vs. 580, p&amp;lt; 0.05), secondary (29 vs. 82, p&amp;lt; 0.05) and antral follicles (5 vs. 23, p&amp;lt; 0.05). The numbers of GV oocytes (18 vs. 37, p&amp;lt; 0.05) and MII oocytes (2 vs. 16, p&amp;lt; 0.001) were lower in the Mff-/- mice than the WT mice. In addition, the Mff-/- ovaries expressed significantly less mitochondrial fission key regulator DRP1 (0.54 vs. 1, p&amp;lt; 0.05). Mff-/- oocytes contained elongated and aggregated mitochondria compared to the discrete and evenly distributed mitochondria in the ooplasm of WT oocytes. Herein, we found that the Mff played a concerted role in oocyte and follicle development. Limitations, reasons for caution The present observations in mice may not be applicable to humans. The results are derived global knockout of Mff. It is not known which kind of cell plays a vital role in fertility. Further investigation is needed to explore the regulatory mechanism of Mff in oocyte development and fertility regulation. Wider implications of the findings This study provides important insights into the relationship between mitochondrial dynamics and female fertility. Trial registration number not applicable

P-668 Effects of the active site domain of visfatin on the improvement of ovarian function in 4-vinylcyclohexene diepoxide-induced ovarian failure mice

Abstract Study question Can only the active site of domain of visfatin improve ovarian function in mice with 4-vinylcyclohexene diepoxide (VCD)-induced ovarian failure? Summary answer The active site domain of visfatin improves ovarian function and fertility potential in VCD-induced mice by stimulating the ovarian angiogenesis and early follicular development. What is known already Ovarian aging is a representative unmet need in infertility treatment and many studies have attempted to improve oocytes quality by activating ovarian angiogenesis. Visfatin has been reported to have angiogenic activity. Our previous study reported that visfatin improved ovarian function and fertility potential in aged female mice. However, visfatin has many limitations in developing as a drug due to large molecular weight. Visfatin is composed of two structural domains, and the active site is located in the second structural domain (amino acid residues 181 to 390), which were defined as the active site domain (hereafter A-domain peptide) in this study. Study design, size, duration This is a controlled experimental study using a total of mice with 60 VCD-induced ovarian failure. The duration of this study was from January to November 2022. Participants/materials, setting, methods C57BL/6 female mice were randomly divided into six groups: Five groups received 160mg/kg VCD and one group received an equal volume of vehicle. Four VCD groups were intraperitoneally injected three times at intervals of 2 days with 500 and 1000 ng/ml of full-size visfatin and A-domain peptide, respectively. The remaining one group served as a negative control. After final treatment, follicular development, gene expression, AMH level, and fertility potential were examined. Main results and the role of chance In hematoxylin and eosin (H&amp;E) staining, numbers of functional follicles including primordial, primary, secondary, and antral follicles were significantly decreased in the VCD-vehicle group compared to the control. However, treatment of full-size visfatin and A-domain peptide increased the number of primordial and primary follicle. On immnohistochemistry (IHC), expression of BMP15, C-KIT, VEGF, and visfatin in ovarian tissues were significantly reduced in the VCD-vehicle group, but immunoreactivity of these factors strongly stained in the treatment of full-size visfatin and A-domain peptide. This effect was more remarkable in 500 ng/ml of A-domain peptide compared to other treatments. The serum AMH level was significantly lower in the VCD-vehicle group compared to the control group, but it was increased after the treatment with A-domain peptide and full-size visfatin. Limitations, reasons for caution This study does not elucidate a clear mechanism how A-domain peptide increases the ovarian function and fertility of VCD-induced ovarian failure mice although it stimulated the expression of genes associated with early follicular development and angiogenesis. Also, generalizability to humans may be limited because the study was conducted in mice. Wider implications of the findings This study suggests that administration of A-domain peptide could be applied as a new treatment strategy for ovarian aging, presumably by activating ovarian angiogenesis and dormant primordial follicles. Trial registration number Not applicable

Primordial follicles remaining in young cancer survivors who received chemotherapy.

Ovarian tissue cryopreservation (OTC) is performed for fertility preservation in cancer patients undergoing chemotherapy. Although anti-Müllerian hormone is used as a marker for ovarian reserve, serum levels do not always correlate with the number of follicles. Additionally, the follicle development stage most affected by chemotherapy is unclear. We examined the association between serum anti-Müllerian hormone levels and the number of remaining primordial follicles after chemotherapy, as well as which follicle stage is most affected by chemotherapy before ovarian cryopreservation. Thirty-three patients who underwent OTC were divided into the chemotherapy (n = 22) and non-chemotherapy (n = 11) groups; their ovarian tissues underwent histological examination. Pathological ovarian damage induced by chemotherapy was assessed. Ovarian volumes were estimated from weights. We compared the number of follicles at each developmental stage as a percentage of primordial follicles between the groups. The relationship between serum anti-Müllerian hormone level and primordial follicle density was analyzed. The chemotherapy group had a significantly lower serum anti-Müllerian hormone level, ovarian volume, and density of developing follicles than the non-chemotherapy group. Serum anti-Müllerian hormone levels correlated with primordial follicle density only in the non-chemotherapy group. The chemotherapy group had significantly lower numbers of primary and secondary follicles. Chemotherapy induces ovarian damage and follicle loss. However, serum anti-Müllerian hormone level does not always reflect the number of primordial follicles after chemotherapy, and chemotherapy more significantly affects primary and secondary follicles than primordial follicles. Many primordial follicles remain in the ovary after chemotherapy, supporting OTC for fertility preservation.

The effect of maternal separation stress-induced depression on ovarian reserve in Sprague Dawley Rats: The possible role of imipramine and agmatine through a mTOR signal pathway

PurposeTo examine the possible role of impramine and agmatine through a mTOR signal pathway on rat ovary after maternal separation stress-induced depression. MethodsSprague Dawley neonatal female rats were divided into control, maternal separation (MS), MS+imipramine, and MS+agmatine groups. Rats were subjected to MS for 4 hours daily from postnatal day (PND) 2 to PND 21 and pups were exposed to social isolation (SI) on PND23 for 37 days for model establishment treated with imipramine (30 mg/kg; ip) or agmatine (40 mg/kg; ip) for 15 days. In order to examine behavioral changes rats were all subjected to locomotor activity and forced swimming tests (FST). Ovaries were isolated for morphological evaluation, follicle counting and mTOR signal pathway protein expression levels were detected. ResultsIncreased number of primordial follicles and diminished ovarian reserve in the MS groups were detected. Imipramine treatment caused diminished ovarian reserve and atretic follicle; however, agmatine treatment provided the maintenance of ovarian follicular reserve after MS. mTOR signal pathway may have an important role during rat ovarian follicular development in model of MS. ConclusionsOur findings suggest that agmatine may help to protect ovarian reserve during follicular development by controlling cell growth.

Ovaries out of control – hormonal strategies

The perimenopausal transition represents a therapeutic challenge for clinicians as the follicular activity of the ovaries does not decline gradually and evenly, but is accompanied by a pronounced up and down of hormone production. The female menstrual cycle involves a highly regulated chain of neuro-endocrine phenomena, maintained by a constant dialogue between the hypothalamus, the pituitary gland and the ovaries. Besides FSH, LH, estradiol and progesterone, other components of this dialogue are inhibin A and B, AMH as well as the KNDy neurons in the arcuate nucleus. Approaching menopause the number of primordial follicles declines to a critically low level. As a result a series of endocrine changes occur and the highly coordinated feed-back loops between the regulating levels is increasingly disturbed. The pituitary-ovarian axis is no longer subject to the laws of the fertile phase: Follicular activity fluctuates and there are periods of estrogen excess alternating with periods of estrogen deficiency. Luteal insufficiencies and anovulation increasingly occur and asynchronous maturation of follicles can lead to so-called "LOOP-events" = "luteal out of phase-events. The strongly fluctuating levels of steroidal hormones can lead to pronounced bleeding disorders and may be responsible for sleep disturbances and depressive moods, both typical symptoms of the early and mid perimenopausal transition.

Brown adipose tissue-derived exosomes delay fertility decline in aging mice.

Ovarian aging has steadily grown to be a significant health issue for women as a result of the increase in average life expectancy and the postponement of reproductive age. One of the important pathological foundations of ovarian aging is formed by mitochondrial dysfunction, which causes decreases in follicle quantity and oocyte quality. In recent years, brown adipose tissue (BAT) transplantation has been proven as an effective treatment for aging-related diseases, such as ovarian aging. However, BAT transplantation is an invasive operation with long-term risks. Therefore, we need to find an alternative strategy. We injected BAT-derived exosomes into eight-month-old C57BL/6 female mice. The fertility was detected by the estrous cycle and mating test. The changes of ovary and oocyte were measured by ovarian volume, organ coefficient, follicle counting, and oocyte maturation rate. ROS level, mitochondrial membrane potential and ATP level were measured to analyze the mitochondrial function of oocytes. The changes in metabolism were explored by cold stimulation test, body weight and blood sugar. The possible molecular mechanism was further investigated by RNA sequencing. In terms of fertility, the estrous cycle of aging mice after BAT-derived exosome intervention was more regular, and the number of progenies and litters was increased. At the tissue level, the ovaries in the BAT-exosome group were larger, and the number of primordial follicles, secondary follicles, antral follicles and total follicles increased. At the cellular level, BAT-derived exosomes improved the maturation of oocytes in vivo and in vitro, increased the mitochondrial membrane potential and ATP levels of oocytes, and decreased ROS levels. Besides, BAT-derived exosomes ameliorated the metabolism and viability of aging mice. Furthermore, mRNA sequencing showed that BAT exosomes altered the expression levels of genes related to metabolism and the quality of oocytes. BAT-derived exosomes enhanced mitochondrial function, promoted follicle survival, improved fertility, and extended ovarian lifespan in aging mice.

Chemotherapy impairs ovarian function through excessive ROS-induced ferroptosis

Chemotherapy was conventionally applied to kill cancer cells, but regrettably, they also induce damage to normal cells with high-proliferative capacity resulting in cardiotoxicity, nephrotoxicity, peripheral nerve toxicity, and ovarian toxicity. Of these, chemotherapy-induced ovarian damages mainly include but are not limited to decreased ovarian reserve, infertility, and ovarian atrophy. Therefore, exploring the underlying mechanism of chemotherapeutic drug-induced ovarian damage will pave the way to develop fertility-protective adjuvants for female patients during conventional cancer treatment. Herein, we firstly confirmed the abnormal gonadal hormone levels in patients who received chemotherapy and further found that conventional chemotherapeutic drugs (cyclophosphamide, CTX; paclitaxel, Tax; doxorubicin, Dox and cisplatin, Cis) treatment significantly decreased both the ovarian volume of mice and the number of primordial and antral follicles and accompanied with the ovarian fibrosis and reduced ovarian reserve in animal models. Subsequently, Tax, Dox, and Cis treatment can induce the apoptosis of ovarian granulosa cells (GCs), likely resulting from excessive reactive oxygen species (ROS) production-induced oxidative damage and impaired cellular anti-oxidative capacity. Thirdly, the following experiments demonstrated that Cis treatment could induce mitochondrial dysfunction through overproducing superoxide in GCs and trigger lipid peroxidation leading to ferroptosis, first reported in chemotherapy-induced ovarian damage. In addition, N-acetylcysteine (NAC) treatment could alleviate the Cis-induced toxicity in GCs by downregulating cellular ROS levels and enhancing the anti-oxidative capacity (promoting the expression of glutathione peroxidase, GPX4; nuclear factor erythroid 2-related factor 2, Nrf2 and heme oxygenase-1, HO-1). Our study confirmed the chemotherapy-induced chaotic hormonal state and ovarian damage in preclinical and clinical examination and indicated that chemotherapeutic drugs initiated ferroptosis in ovarian cells through excessive ROS-induced lipid peroxidation and mitochondrial dysfunction, leading to ovarian cell death. Consequently, developing fertility protectants from the chemotherapy-induced oxidative stress and ferroptosis perspective will ameliorate ovarian damage and further improve the life quality of cancer patients.

Circadian regulation of mTORC1 signaling via Per2 dependent mechanism disrupts folliculogenesis and oocyte maturation in female mice.

mTOR (mammalian target of Rapamycin) is an important signaling pathway involved in several crucial ovarian functions including folliculogenesis and oocyte maturation. The circadian rhythm regulates multiple physiological processes and PER2 is one of the core circadian rhythm components. mTOR is regulated by the circadian clock and in turn, the rhythmic mTOR activities strengthen the clock function. Our current study aims to investigate a possible interconnection between the circadian clock and the mTORC1 signaling pathway in folliculogenesis and oocyte maturation. Here we demonstrate that the circadian system regulates mTORC1 signaling via Per2 dependent mechanism in the mouse ovary. To investigate the effect of constant light on ovarian and oocyte morphology, animals were housed 12:12h L:D group in standard lightening conditions and the 12:12h L:L group in constant light for one week. Food intake and body weight changes were measured. Ovarian morphology, follicle counting, and oocyte aging were evaluated. Afterward, western blot for mTOR, p-mTOR, p70S6K, p-p70S6K, PER2, and Caspase-3 protein levels was performed. The study demonstrated that circadian rhythm disruption caused an alteration in their food intake and decrease in primordial follicle numbers and an increase in the number of atretic follicles. It caused an increase in oxidative stress and a decrease in ZP3 expression in oocytes. Decreased protein levels of mTOR, p-mTOR, p70S6K, and PER2 were shown. The results showed that the circadian clock regulates mTORC1 through PER2 dependent mechanism and that decreased mTORC1 activity can contribute to premature aging of mouse ovary. In conclusion, these results suggest that the circadian clock may control ovarian aging by regulating mTOR signaling pathway through Per2 expression.

Preantral follicle numbers and size in heifers carrying Trio, a bovine high fecundity allele.

The bovine high fecundity allele, Trio, results in the occurrence of multiple ovulations and is characterized by antral follicles that develop slower and acquire ovulatory capacity at smaller sizes. This study provides novel information on the effect of the Trio allele on early folliculogenesis. The bovine high fecundity allele, Trio, causes overexpression in granulosa cells (GCs) of SMAD6, an inhibitor of BMP15-activated SMAD signalling. Furthermore, the Trio allele results in antral follicles that develop slower, acquire ovulatory capacity at smaller sizes, and have three-fold greater ovulation rate compared to half-sib non-carriers. The present study was designed to determine preantral follicle numbers and size in Trio carrier and non-carrier cattle testing the hypothesis that inhibition of SMAD signalling would alter preantral follicle activation and/or growth. Ovarian tissues from Trio carrier (n = 12) and non-carrier (n = 12) heifers were obtained by laparotomy after follicle wave synchronization. Follicle numbers and dimensions were determined for each stage of development (primordial, transitional, primary, and secondary) from paraffin-embedded sections. There were no differences in the number of primordial, transitional, or secondary follicles or in antral follicle count, circulating AMH, or ovarian volume between carriers and non-carriers. Trio carriers had ~2.5-fold greater (P < 0.01) number of primary follicles than non-carriers, and transitional and primary follicles were larger (~1.2-fold; P < 0.1) in Trio carriers. Oocyte volume of primordial and transitional follicles was not different between genotypes; however, oocytes were larger (P < 0.05) in primary (~1.3-fold) and secondary (~1.8-fold) follicles for Trio carriers. Granulosa cell numbers were not different (P > 0.3) between carriers and non-carriers, irrespective of the stage of development. These results suggest that, after primordial follicle activation, follicles in Trio carrier cattle have slower progression through the primary stage, hence the larger oocyte and greater number of primary follicles.

Pubertal lead exposure affects ovary development, folliculogenesis and steroidogenesis by activation of IRE1α-JNK signaling pathway in rat

Epidemic studies showed that lead exposures are associated with various female reproductive dysfunctions, including infertility, miscarriage, preterm delivery, and early menopause. However, the mechanism involved is still unclear. In the current study, SD rats were exposed to lead at doses of 0, 5, 25, 50 or 250 mg/L through drinking water from postnatal day 21–56. Lead exposures did not affect the body weight or ovary weight. However, the puberty initiation (ages by which vagina opens and estrous cycle occurs) was significantly delayed by as many as 5.8 and 6.8 days respectively (P < 0.05). Also, lead exposures disrupted the estrous cycles, reduced the numbers of primordial and primary follicles and increased the number of atretic follicles by adult. Furthermore, for the highest does group, serum levels of progesterone and testosterone decreased by 80.2% (P < 0.01) and 49.9% (P < 0.05) respectively, while estradiol level increased by 69.8% (P < 0.01). Western blot analyses indicated that lead exposures specifically down-regulated the expressions of steroidogenic protein STAR, CYP17A1, and HSD3B1, while up-regulated FSHR and CYP19A1. Also, the exposure stimulated the endoplasmic reticulum stress (ERS)-related IRE1α-JNK signaling pathway members. Such activation may also result in apoptosis since the death-signaling molecules CHOP and cleaved-CASP3 were up-regulated while BCL2 was down-regulated. In conclusion, lead exposure during juvenile and puberty significantly affected ovary development and functions. The effects may relate to ERS response since the 6 members related to the pathway were all consistently activated.

Adipose-derived stem cells promote the repair of chemotherapy-induced premature ovarian failure by inhibiting granulosa cells apoptosis and senescence

BackgroundChemotherapeutic drugs, particularly alkylating cytotoxics such as cyclophosphamide (CTX), play an important role to induce premature ovarian failure (POF). Hormone replacement therapy (HRT) is a widely used treatment to improve hormone secretion. However, the long-term HRT increases the risk of breast cancer and cardiovascular disease are attracting concerns. Therefore, there is an urgent need to develop a safe and effective treatment for POF.MethodAdipose-derived stem cells (ADSCs) were isolated and identified from human adipose tissue. For POF modeling, CTX were intraperitoneal injected into CTX-acute group, CTX-chronic group, CTX-acute + ADSCs group and CTX-chronic + ADSCs group rats; For transplantation, ADSCs were transplanted into POF rats through tail-vein. The control group rats were injected with PBS. The effects of POF modeling and transplantation were determined by estrous cycle analysis, histopathological analysis, immunohistochemical staining and apoptosis-related marker. To evaluate the effects of ADSC on granulosa cells in vitro, CTX-induced senescent KGN cells were co-cultured with ADSCs, and senescent-related marker expression was investigated by immunofluorescent staining.ResultsIn vivo studies revealed that ADSCs transplantation reduced the apoptosis of ovarian granulosa cells and secretion of follicle-stimulating hormone. The number of total follicles, primordial follicles, primary follicles, and mature follicles and secretion of anti-Müllerian hormone and estradiol (E2) were also increased by ADSCs. The estrous cycle was also improved by ADSC transplantation. Histopathological analysis showed that CTX-damaged ovarian microenvironment was improved by ADSCs. Furthermore, TUNEL staining indicated that apoptosis of granulosa cells was decreased by ADSCs. In vitro assay also demonstrated that ADSC markedly attenuated CTX-induced senescence and apoptosis of granulosa cell. Mechanistically, both in vivo and in vitro experiments proved that ADSC transplantation suppressed activation of the PI3K/Akt/mTOR axis.ConclusionOur experiment demonstrated that a single injection of high-dose CTX was a less damaging chemotherapeutic strategy than continuous injection of low-dose CTX, and tail-vein injection of ADSCs was a potential approach to promote the restoration of CTX-induced POF.

In vitro exposure to benzo[a]pyrene damages the developing mouse ovary.

Females are born with a finite number of oocytes, collectively termed the ovarian reserve, established within the developing fetal ovary. Consequently, maternal exposure to reproductive toxicants can have harmful effects on the future fertility of her unborn female fetus. The chemical benzo[a]pyrene (B[a]P) is a prominent component of cigarette smoke. Despite it being a known ovotoxicant, around 8% of women in Europe smoke during pregnancy. The purpose of this research was to examine the effect of B[a]P on the developing ovary, using the mouse as a model and with experiments carried out in vitro. B[a]P-exposure to the fetal ovary prior to follicle formation reduced the number of germ cells and subsequently, the number of healthy primordial follicles, by up to 76%; however, while proliferation of germ cells was not affected, the germ cells contained higher levels of DNA double-strand breaks. Exposure to B[a]P also affected the proportion of oocytes progressing through prophase I of meiosis. B[a]P exposure to neonatal mouse ovaries, after follicle formation, resulted in an 85% reduction in the number of healthy follicles, with a corresponding increase in apoptotic cell death and reduction in somatic cell proliferation. Although there was a trend towards a higher level of oxidative stress in B[a]P-exposed ovaries, this was not statistically significant; likewise, the antioxidant melatonin failed to protect against the B[a]P-induced ovarian damage. Together, the results here demonstrate that B[a]P-exposure damages the developing ovary, both before and shortly after follicle formation, an effect that could lead to a subsequent decrease in fertility.

Resveratrol alleviates doxorubicin-induced damage in mice ovary

While oocytes and embryos cryopreservation can favor some patients with cancer-induced infertility to achieve pregnancy, the development of effective therapeutic strategies to preserve ovarian function during chemotherapy would be a significant advantage. The aim of the present study is to analyze whether Resveratrol treatment (Res) can preserve ovarian function from doxorubicin (Doxo)-induced gonadotoxicity using a mice model of premature ovarian failure. Res (7 and 15 mg/kg) increased the percentage of primary and antral follicles whilst decreasing the percentage of atretic follicles compared to Doxo alone. Res preserved the number of primordial follicles compared with those in the Doxo group but they did not change from those in the control group. Res treatment increased the number of AMH positive follicles compared to Doxo alone. Res increased proliferation index in follicular cells and reduced the DNA damage and apoptosis in preantral and early antral follicles compared to Doxo alone. Additionally, Doxo administration caused a severe endothelial damage and affected microvasculature stability in the ovary. However, Res was able to increase the recruitment of pericytes and smooth muscle cells in the Doxo-treated group. We also found that Res increased the expression of VEGF compared to Doxo alone. By H&E staining, Doxo-treated mice demonstrated endometrial alterations compared to controls, affecting both epithelial and stromal compartments. Nonetheless, Res restored the architecture of uterine tissue. Moreover, we also showed that Res administration is able to maintain antioxidant defenses through the increase of SOD expression in the Doxo-induced POF model.In conclusion, Res administration prior to and during Doxo treatment might serve as a noninvasive and low-cost protocol to preserve ovarian function in female cancer survivors.