Inhibitors of apoptosis protect the ovarian reserve from cyclophosphamide

Ovarian microenvironment: challenges and opportunities in protecting against chemotherapy-associated ovarian damage

BACKGROUND

Chemotherapy-associated ovarian damage (CAOD) is one of the most feared short- and long-term side effects of anticancer treatment in premenopausal women. Accumulating detailed data show that different chemotherapy regimens can lead to disturbance of ovarian hormone levels, reduced or lost fertility, and an increased risk of early menopause. Previous studies have often focused on the direct effects of chemotherapeutic drugs on ovarian follicles, such as direct DNA damage-mediated apoptotic death and primordial follicle burnout. Emerging evidence has revealed an imbalance in the ovarian microenvironment during chemotherapy. The ovarian microenvironment provides nutritional support and transportation of signals that stimulate the growth and development of follicles, ovulation, and corpus luteum formation. The close interaction between the ovarian microenvironment and follicles can determine ovarian function. Therefore, designing novel and precise strategies to manipulate the ovarian microenvironment may be a new strategy to protect ovarian function during chemotherapy.

OBJECTIVE AND RATIONALE

This review details the changes that occur in the ovarian microenvironment during chemotherapy and emphasizes the importance of developing new therapeutics that protect ovarian function by targeting the ovarian microenvironment during chemotherapy.

SEARCH METHODS

A comprehensive review of the literature was performed by searching PubMed up to April 2024. Search terms included 'ovarian microenvironment' (ovarian extracellular matrix, ovarian stromal cells, ovarian interstitial, ovarian blood vessels, ovarian lymphatic vessels, ovarian macrophages, ovarian lymphocytes, ovarian immune cytokines, ovarian oxidative stress, ovarian reactive oxygen species, ovarian senescence cells, ovarian senescence-associated secretory phenotypes, ovarian oogonial stem cells, ovarian stem cells), terms related to ovarian function (reproductive health, fertility, infertility, fecundity, ovarian reserve, ovarian function, menopause, decreased ovarian reserve, premature ovarian insufficiency/failure), and terms related to chemotherapy (cyclophosphamide, lfosfamide, chlormethine, chlorambucil, busulfan, melphalan, procarbazine, cisplatin, doxorubicin, carboplatin, taxane, paclitaxel, docetaxel, 5-fluorouraci, vincristine, methotrexate, dactinomycin, bleomycin, mercaptopurine).

OUTCOMES

The ovarian microenvironment shows great changes during chemotherapy, inducing extracellular matrix deposition and stromal fibrosis, angiogenesis disorders, immune microenvironment disturbance, oxidative stress imbalances, ovarian stem cell exhaustion, and cell senescence, thereby lowering the quantity and quality of ovarian follicles. Several methods targeting the ovarian microenvironment have been adopted to prevent and treat CAOD, such as stem cell therapy and the use of free radical scavengers, senolytherapies, immunomodulators, and proangiogenic factors.

WIDER IMPLICATIONS

Ovarian function is determined by its 'seeds' (follicles) and 'soil' (ovarian microenvironment). The ovarian microenvironment has been reported to play a vital role in CAOD and targeting the ovarian microenvironment may present potential therapeutic approaches for CAOD. However, the relation between the ovarian microenvironment, its regulatory networks, and CAOD needs to be further studied. A better understanding of these issues could be helpful in explaining the pathogenesis of CAOD and creating innovative strategies for counteracting the effects exerted on ovarian function. Our aim is that this narrative review of CAOD will stimulate more research in this important field.

REGISTRATION NUMBER

Not applicable.

Chemotherapy drug combinations induced maternal ovarian damage and long-term effect on fetal reproductive system in mice

With the postponement of female reproductive age and the higher incidence of cancer in young people, fertility preservation has become increasingly important in childbearing age. Chemotherapy during pregnancy is crucial for maternal cancer treatments and fetal outcomes. It is a need to further study ovarian damage caused by chemotherapy drug combinations and long-term effects on offspring development, and a detailed understanding of side effects of chemotherapy drugs. In this study, chemotherapy drug combinations significantly impacted on ovarian function, especially epirubicin/cyclophosphamide (EC) combination led to an unbalance in the development of the left and right ovary. Exposure to EC and cisplatin/paclitaxel (TP) increased the number of progenitor follicles while decreased the count of antral follicles and corpora luteum. As to the estrus cycle, EC exposure resulted in a longer estrus period and diestrus period, while TP exposure only extended the diestrus period. EC and TP affected steroid biosynthesis by reducing the expression of SF1 and P450arom.γ-H2AX was detected in both EC and TP exposure groups. As to the impact on the offspring from 4T1 tumor-bearing pregnant mice injected with EC, no significant difference was observed in the physical and neurological development compared to the control, but the ovarian weights, estrus cycles of the offspring were significantly different. Chemotherapy drug combinations exhibit ovarian toxicity, not only causing direct damage on the follicle cells but also disrupting steroid biosynthesis. The reproductive system of offspring from maternal tumor-bearing mice exposed to chemotherapy drugs was observed disorder, but the concrete mechanism still needs further exploration.

Mechanism study of YangJing ZhongYu decoction on regulating mitochondrial dynamics of ovarian granular cells and improving diminished ovarian reserve

OBJECTIVE

Diminished ovarian reserve (DOR) encompasses both reproductive and endocrine disorders, resulting in a decline in female fertility. This paper explored the mechanism of Yangjing Zhongyu Decoction (YJZYD) regulating mitochondrial dynamics of ovarian granulosa cells (GCs) to improve DOR.

METHODS

DOR patients were treated with YJZYD, with ovarian volume (OV), antral follicle count (AFC), and endometrial thickness (EMT) detected. C57BL/6 female mice were treated by cyclophosphamide (Cy) intraperitoneal injection and YJZYD solution daily gavage, with serum anti-Mullerian hormone (AMH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E2) levels determined. Ovarian GCs (KGN) were interfered with 4-Hydroperoxy-Cyclophosphamide (4-HC) and treated with the MAPK/ERK pathway inhibitor or activator.

RESULTS

DOR patients showed increased levels of serum AMH, E2, OV, AFC and EMT, while reduced FSH and LH levels after YJZYD treatment. After Cy induction, DOR mice exhibited irregular estrous cycles, diminished serum AMH and E2 levels, elevated FSH and LH levels, reduced follicle number and atresia follicle number, disorderly arranged GCs, and severe interstitial fibrosis. After 4-HC treatment, KGN proliferation and Bcl-2, MFN1, and MFN2 were suppressed, while apoptotic rate, Bax, Cleaved-caspase-3, and p-Drp1 (Ser616) levels, and mitochondrial fission and quantity increased. YJZYD promoted 4-HC-treated KGN proliferation, boosted mitochondrial fusion, and inhibited apoptosis and mitochondrial fission via the MAPK/ERK pathway.

CONCLUSION

YJZYD promoted ovarian GC proliferation and mitochondrial fusion, suppressed cell apoptosis and mitochondrial fission, and effectively improved DOR in mice by activating the MAPK/ERK pathway, providing a theoretical basis for the clinical application value of YJZYD in DOR treatment.

An overview of different methods to establish a murine premature ovarian failure model

Premature ovarian failure (POF)is defined as the loss of normal ovarian function before the age of 40 and is characterized by increased gonadotropin levels and decreased estradiol levels and ovarian reserve, often leading to infertility. The incomplete understanding of the pathogenesis of POF is a major impediment to the development of effective treatments for this disease, so the use of animal models is a promising option for investigating and identifying the molecular mechanisms involved in POF patients and developing therapeutic agents. As mice and rats are the most commonly used models in animal research, this review article considers studies that used murine POF models. In this review based on the most recent studies, first, we introduce 10 different methods for inducing murine POF models, then we demonstrate the advantages and disadvantages of each one, and finally, we suggest the most practical method for inducing a POF model in these animals. This may help researchers find the method of creating a POF model that is most appropriate for their type of study and suits the purpose of their research.

In-depth analysis of transcriptomes in ovarian cortical follicles from children and adults reveals interfollicular heterogeneity

The ovarian cortical reserve of follicles is vital for fertility. Some medical treatments are toxic to follicles, leading to premature ovarian insufficiency. Ovarian tissue cryopreservation is an established method to preserve fertility in adults and even applied in prepuberty despite unproven efficacy. Here, we analyze transcriptomes of 120 cortical follicles from children and adults for detailed comparison. We discover heterogeneity with two main types of follicles in both age groups: one with expected oocyte-granulosa profiles and another with predicted role in signaling. Transcriptional changes during growth to the secondary stage are similar overall in children and adults, but variations related to extracellular matrix, theca cells, and miRNA profiles are found. Notably, cyclophosphamide dose correlates with interferon signaling in child follicles. Additionally, morphology alone is insufficient for follicle categorization suggesting a need for additional markers. Marker genes for early follicle activation are determined. These findings will help refine follicular classification and fertility preservation techniques across critical ages.

Gonadotropin Activity during Early Folliculogenesis and Implications for Polycystic Ovarian Syndrome and Premature Ovarian Insufficiency: A Narrative Review

Female fertility depends on the ovarian reserve of follicles, which is determined at birth. Primordial follicle development and oocyte maturation are regulated by multiple factors and pathways and classified into gonadotropin-independent and gonadotropin-dependent phases, according to the response to gonadotropins. Folliculogenesis has always been considered to be gonadotropin-dependent only from the antral stage, but evidence from the literature highlights the role of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) during early folliculogenesis with a potential role in the progression of the pool of primordial follicles. Hormonal and molecular pathway alterations during the very earliest stages of folliculogenesis may be the root cause of anovulation in polycystic ovary syndrome (PCOS) and in PCOS-like phenotypes related to antiepileptic treatment. Excessive induction of primordial follicle activation can also lead to premature ovarian insufficiency (POI), a condition characterized by menopause in women before 40 years of age. Future treatments aiming to suppress initial recruitment or prevent the growth of resting follicles could help in prolonging female fertility, especially in women with PCOS or POI. This review will briefly introduce the impact of gonadotropins on early folliculogenesis. We will discuss the influence of LH on ovarian reserve and its potential role in PCOS and POI infertility.

The role of declining ataxia-telangiectasia-mutated (ATM) function in oocyte aging

Despite the advances in the understanding of reproductive physiology, the mechanisms underlying ovarian aging are still not deciphered. Recent research found an association between impaired ATM-mediated DNA double-strand break (DSB) repair mechanisms and oocyte aging. However, direct evidence connecting ATM-mediated pathway function decline and impaired oocyte quality is lacking. The objective of this study was to determine the role of ATM-mediated DNA DSB repair in the maintenance of oocyte quality in a mouse oocyte knockdown model. Gene interference, in vitro culture, parthenogenesis coupled with genotoxicity assay approaches, as well as molecular cytogenetic analyses based upon next-generation sequencing, were used to test the hypothesis that intact ATM function is critical in the maintenance of oocyte quality. We found that ATM knockdown impaired oocyte quality, resulting in poor embryo development. ATM knockdown significantly lowered or blocked the progression of meiosis in vitro, as well as retarding and reducing embryo cleavage after parthenogenesis. After ATM knockdown, all embryos were of poor quality, and none reached the blastocyst stage. ATM knockdown was also associated with an increased aneuploidy rate compared to controls. Finally, ATM knockdown increased the sensitivity of the oocytes to a genotoxic active metabolite of cyclophosphamide, with increased formation of DNA DSBs, reduced survival, and earlier apoptotic death compared to controls. These findings suggest a key role for ATM in maintaining oocyte quality and resistance to genotoxic stress, and that the previously observed age-induced decline in oocyte ATM function may be a prime factor contributing to oocyte aging.

Ovarian function in patients with systemic lupus erythematosus: Pathogenesis, drug application and prospective therapies

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease in which multiple organs are damaged that prevails in fertile women. Currently, glucocorticoids and immunosuppressants are widely used to treat SLE patients. However, ovarian dysfunction occurs following the use of these drugs in women with SLE. Here, we summarize recent progress in terms of understanding ovarian injury, the effects of drug application and strategies to improve ovarian function in women with SLE. This review could be helpful to precisely cure SLE in women desiring to have offspring.

Gynotoxic Effects of Chemotherapy and Potential Protective Mechanisms

Chemotherapy is one of the leading cancer treatments. Unfortunately, its use can contribute to several side effects, including gynotoxic effects in women. Ovarian reserve suppression and estrogen deficiency result in reduced quality of life for cancer patients and are frequently the cause of infertility and early menopause. Classic alkylating cytostatics are among the most toxic chemotherapeutics in this regard. They cause DNA damage in ovarian follicles and the cells they contain, and they can also induce oxidative stress or affect numerous signaling pathways. In vitro tests, animal models, and a few studies among women have investigated the effects of various agents on the protection of the ovarian reserve during classic chemotherapy. In this review article, we focused on the possible beneficial effects of selected hormones (anti-Müllerian hormone, ghrelin, luteinizing hormone, melatonin), agents affecting the activity of apoptotic pathways and modulating gene expression (C1P, S1P, microRNA), and several natural (quercetin, rapamycin, resveratrol) and synthetic compounds (bortezomib, dexrazoxane, goserelin, gonadoliberin analogs, imatinib, metformin, tamoxifen) in preventing gynotoxic effects induced by commonly used cytostatics. The presented line of research appears to provide a promising strategy for protecting and/or improving the ovarian reserve in the studied group of cancer patients. However, well-designed clinical trials are needed to unequivocally assess the effects of these agents on improving hormonal function and fertility in women treated with ovotoxic anticancer drugs.

Atorvastatin improves ovarian function and follicular reserve in rats with premature ovarian insufficiency

RESEARCH QUESTION

Can atorvastatin, with its antioxidant, anti-inflammatory and anti-apoptotic properties, improve ovarian function and follicular reserve in rats with cyclophosphamide-induced premature ovarian insufficiency (POI)?

DESIGN

In this experimental study, 24 adult female Wistar rats were divided into four groups: control; POI; POI + atorvastatin; and atorvastatin. After treatment with atorvastatin, serum concentrations of total antioxidant capacity, glutathione, malondialdehyde, FSH, oestradiol, anti-Müllerian hormone, tumour necrosis factor-alpha and interleukin-6 were evaluated. Additionally, mRNA and protein expression of Bax, Bcl-2 and VEGF-A; number of follicles; and total volume of the ovary, and volumes of the cortex and medulla were examined.

RESULTS

The results showed that serum concentrations of total antioxidant capacity (P < 0.001), glutathione, oestradiol and anti-Müllerian hormone (P < 0.05); mRNA and protein expression of Bcl-2 and VEGF-A (P < 0.05); number of primordial and primary follicles (P < 0.001), and preantral and antral follicles (P < 0.01); and total volume of the ovary, and volume of the cortex (P < 0.05) increased significantly in the POI + atorvastatin group compared with the POI group. Serum concentrations of malondialdehyde, FSH, tumour necrosis factor-alpha and interleukin-6; and mRNA and protein expression of Bax decreased significantly in the POI + atorvastatin group compared with the POI group (P < 0.05).

CONCLUSIONS

Atorvastatin reduces the detrimental effects of cyclophosphamide in the POI model significantly by reducing oxidative stress and pro-inflammatory cytokines; regulating the expression of Bax, Bcl-2 and VEGF-A; and improving ovarian function and follicular reserve.

AMH protects the ovary from doxorubicin by regulating cell fate and the response to DNA damage

Anti-Müllerian hormone (AMH) protects the ovarian reserve from chemotherapy, and this effect is most pronounced with Doxorubicin (DOX). However, the mechanisms of DOX toxicity and AMH rescue in the ovary remain unclear. Herein, we characterize these mechanisms in various ovarian cell types using scRNAseq. In the mesenchyme, DOX activates the intrinsic apoptotic signaling pathway through p53 class mediators, particularly affecting theca progenitors, while co-treament with AMH halts theca differentiation and reduces apoptotic gene expression. In preantral granulosa cells, DOX upregulates the cell cycle inhibitor Cdkn1a and dysregulates Wnt signaling, which are ameliorated by AMH co-treatment. Finally, in follicles, AMH induces Id3 , a protein involved in DNA repair, which is necessary to prevent the accumulation of DNA lesions marked by γ-H2AX in granulosa cells. Altogether this study characterizes cell, and follicle stage-specific mechanisms of AMH protection of the ovary, offering promising new avenues for fertility preservation in cancer patients undergoing chemotherapy.

Highlights

Doxorubicin treatment induces DNA damage that activates the p53 pathway in stromal and follicular cells of the ovary.AMH inhibits the proliferation and differentiation of theca and granulosa cells and promotes follicle survival following Doxorubicin insult.AMH treatment mitigates Doxorubicin-induced DNA damage in the ovary by preventing the accumulation of γ-H2AX-positive unresolved foci, through increased expression of ID3, a protein involved in DNA repair.

Rapamycin prevents cyclophosphamide-induced ovarian follicular loss and potentially inhibits tumour proliferation in a breast cancer xenograft mouse model

STUDY QUESTION

To what extent and via what mechanism does the concomitant administration of rapamycin (a follicle activation pathway inhibitor and antitumour agent) and cyclophosphamide (a highly toxic ovarian anticancer agent) prevent cyclophosphamide-induced ovarian reserve loss and inhibit tumour proliferation in a breast cancer xenograft mouse model?

SUMMARY ANSWER

Daily concomitant administration of rapamycin and a cyclic regimen of cyclophosphamide, which has sufficient antitumour effects as a single agent, suppressed cyclophosphamide-induced primordial follicle loss by inhibiting primordial follicle activation in a breast cancer xenograft mouse model, suggesting the potential of an additive inhibitory effect against tumour proliferation.

WHAT IS KNOWN ALREADY

Cyclophosphamide stimulates primordial follicles by activating the mammalian target of the rapamycin (mTOR) pathway, resulting in the accumulation of primary follicles, most of which undergo apoptosis. Rapamycin, an mTOR inhibitor, regulates primordial follicle activation and exhibits potential inhibitory effects against breast cancer cell proliferation.

STUDY DESIGN, SIZE, DURATION

To assess ovarian follicular apoptosis, 3 weeks after administering breast cancer cells, 8-week-old mice were randomized into three treatment groups: control, cyclophosphamide, and cyclophosphamide + rapamycin (Cy + Rap) (n = 5 or 6 mice/group). Mice were treated with rapamycin or vehicle control for 1 week, followed by a single dose of cyclophosphamide or vehicle control. Subsequently, the ovaries were resected 24 h after cyclophosphamide administration (short-term treatment groups). To evaluate follicle abundance and the mTOR pathway in ovaries, as well as the antitumour effects and impact on the mTOR pathway in tumours, 8-week-old xenograft breast cancer transplanted mice were randomized into three treatment groups: vehicle control, Cy, and Cy + Rap (n = 6 or 7 mice/group). Rapamycin (5 mg/kg) or the vehicle was administered daily for 29 days. Cyclophosphamide (120 mg/kg) or the vehicle was administered thrice weekly (long-term treatment groups). The tumour diameter was measured weekly. Seven days after the last cyclophosphamide treatment, the ovaries were harvested, fixed, and sectioned (for follicle counting) or frozen (for further analysis). Similarly, the tumours were resected and fixed or frozen.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) was performed to examine ovarian follicular apoptosis in the short-term treatment groups. All subsequent experiments were conducted in the long-term treatment groups. Tumour growth was evaluated using the tumour volume index. The tumour volume index indicates the relative volume, compared to the volume 3 weeks after tumour cell injection (at treatment initiation) set to 100%. Tumour cell proliferation was evaluated by Ki-67 immunostaining. Activation of the mTOR pathway in tumours was assessed using the protein extracts from tumours and analysed by western blotting. Haematoxylin and eosin staining of ovaries was used to perform differential follicle counts for primordial, primary, secondary, antral, and atretic follicles. Activation of the mTOR pathway in ovaries was assessed using protein extracts from whole ovaries and analysed by western blotting. Localization of mTOR pathway activation within ovaries was assessed by performing anti-phospho-S6 kinase (downstream of mTOR pathway) immunohistochemistry.

MAIN RESULTS AND THE ROLE OF CHANCE

Ovaries of the short-term treatment groups were resected 24 h after cyclophosphamide administration and subjected to TUNEL staining of apoptotic cells. No TUNEL-positive primordial follicles were detected in the control, Cy, and Cy + Rap groups. Conversely, many granulosa cells of growing follicles were TUNEL positive in the Cy group but negative in the control and Cy + Rap groups. All subsequent experimental results were obtained from the long-term treatment groups. The tumour volume index stabilized at a mean of 160-200% in the Cy group and 130% in the Cy + Rap group throughout the treatment period. In contrast, tumours in the vehicle control group grew continuously with a mean tumour volume index of 600%, significantly greater than that of the two treatment groups. Based on the western blot analysis of tumours, the mTOR pathway was activated in the vehicle control group and downregulated in the Cy + Rap group when compared with the control and Cy groups. Ki-67 immunostaining of tumours showed significant inhibition of cell proliferation in the Cy + Rap group when compared with that in the control and Cy groups. The ovarian follicle count revealed that the Cy group had significantly fewer primordial follicles (P < 0.001) than the control group, whereas the Cy + Rap group had significantly higher number of primordial follicles (P < 0.001, 2.5 times) than the Cy group. The ratio of primary to primordial follicles was twice as high in the Cy group than in the control group; however, no significant difference was observed between the control group and the Cy + Rap group. Western blot analysis of ovaries revealed that the mTOR pathway was activated by cyclophosphamide and inhibited by rapamycin. The phospho-S6 kinase (pS6K)-positive primordial follicle rate was 2.7 times higher in the Cy group than in the control group. However, this effect was suppressed to a level similar to the control group in the Cy + Rap group.

LARGE SCALE DATA

None.

LIMITATIONS, REASONS FOR CAUTION

The combinatorial treatment of breast cancer tumours with rapamycin and cyclophosphamide elicited inhibitory effects on cell proliferative potential compared to cyclophosphamide monotherapy. However, no statistically significant additive effect was observed on tumour volume. Thus, the beneficial antitumour effect afforded by rapamycin administration on breast cancer could not be definitively proven. Although rapamycin has ovarian-protective effects, it does not fully counteract the ovarian toxicity of cyclophosphamide. Nevertheless, rapamycin is advantageous as an ovarian protective agent as it can be used in combination with other ovarian protective agents, such as hormonal therapy. Hence, in combination with other agents, mTOR inhibitors may be sufficiently ovario-protective against high-dose and cyclic cyclophosphamide regimens.

WIDER IMPLICATIONS OF THE FINDINGS

Compared with a cyclic cyclophosphamide regimen that replicates human clinical practice under breast cancer-bearing conditions, the combination with rapamycin mitigates the ovarian follicle loss of cyclophosphamide without interfering with the anticipated antitumour effects. Hence, rapamycin may represent a new non-invasive treatment option for cyclophosphamide-induced ovarian dysfunction in breast cancer patients.

STUDY FUNDING/COMPETING INTEREST(S)

This work was not financially supported. The authors declare that they have no conflict of interest.

Research progress on the prevention and treatment of chemotherapy-induced ovarian damage

Chemotherapy is a main treatment option for malignant tumors, but it may cause various adverse effects, including dysfunction of female endocrine system and fertility. Chemotherapy-induced ovarian damage has been concerned with ovarian preservation but also the prevention and treatment of ovarian dysfunction. In this article, the mechanisms of ovarian injury caused by chemotherapy, including apoptosis of the follicle and supporting cells, follicle "burn out", ovarian stromal and microvascular damage; and influencing factors, including age at diagnosis, initial low pre-treatment anti-Müllerian hormone levels, toxicity, dose and regimen of chemotherapy drugs are reviewed based on the latest research results and clinical practice. The article also discusses measures and frontier therapies for the prevention and treatment of ovarian injury, including the application of gonadotropin releasing hormone agonists or antagonists, tyrosine kinase inhibitors, antioxidants, sphingosine-1-phosphate, ceramide-1-phosphate, mammalian target of rapamycin inhibitors, granulocyte-colony stimulating factor, stem cell therapy and artificial ovaries.

The value of low-intensity pulsed ultrasound in reducing ovarian injury caused by chemotherapy in mice

BACKGROUND

Ovarian damage and follicle loss are major side effects of chemotherapy in young female patients with cancer. However, effective strategies to prevent these injuries are still lacking. The purpose of this study was to verify low-intensity pulsed ultrasound (LIPUS) can reduce ovarian injury caused by chemotherapy and to explore its underlying mechanisms in mice model.

METHODS

The mice were randomly divided into the Control group, Cisplatin group, and Cisplatin + LIPUS group. The Cisplatin group and Cisplatin + LIPUS group were intraperitoneally injected with cisplatin every other day for a total of 10 injections, and the Control group was injected with saline. On the second day of each injection, the Cisplatin + LIPUS group received irradiation, whereas the other two groups received sham irradiation. We used a variety of biotechnologies to detect the differences in follicle count, granulosa cell apoptosis, fibrosis, transcriptome level, oxidative damage, and inflammation in differently treated mice.

RESULT

LIPUS was able to reduce primordial follicle pool depletion induced by cisplatin and inhibit the apoptosis of granulosa cells. Transcriptomic results confirmed that LIPUS can reduce ovarian tissue injury. We demonstrated that LIPUS can relieve ovarian fibrosis by inhibiting TGF-β1/Smads pathway. Meanwhile, it can reduce the oxidative damage and reduced the mRNA levels of proinflammatory cytokines caused by chemotherapy.

CONCLUSION

LIPUS can reduce the toxic effects of chemotherapy drugs on ovaries, inhibit ovarian fibrosis, reduce the inflammatory response, and redcue the oxidative damage, reduce follicle depletion and to maintain the number of follicle pools.

Anti-Mullerian hormone attenuates both cyclophosphamide-induced damage and PI3K signalling activation, while rapamycin attenuates only PI3K signalling activation, in human ovarian cortex in vitro

STUDY QUESTION

What are the effects of cyclophosphamide exposure on the human ovary and can anti-Mullerian hormone (AMH) and rapamycin protect against these?

SUMMARY ANSWER

Exposure to cyclophosphamide compromises the health of primordial and transitional follicles in the human ovarian cortex and upregulates PI3K signalling, indicating both direct damage and increased follicular activation; AMH attenuates both of these chemotherapy-induced effects, while rapamycin attenuates only PI3K signalling upregulation.

WHAT IS KNOWN ALREADY

Studies primarily in rodents demonstrate that cyclophosphamide causes direct damage to primordial follicles or that the primordial follicle pool is depleted primarily through excessive initiation of follicle growth. This increased follicular activation is mediated via upregulated PI3K signalling and/or reduced local levels of AMH production due to lost growing follicles. Furthermore, while rodent data show promise regarding the potential benefits of inhibitors/protectants alongside chemotherapy treatment to preserve female fertility, there is no information about the potential for this in humans.

STUDY DESIGN, SIZE, DURATION

Fresh ovarian cortical biopsies were obtained from 17 healthy women aged 21-41 years (mean ± SD: 31.8 ± 4.9 years) at elective caesarean section. Biopsies were cut into small fragments and cultured for 24 h with either vehicle alone (DMSO), the active cyclophosphamide metabolite 4-hydroperoxycyclophosphamide (4-HC) alone, 4-HC + rapamycin or 4-HC+AMH. Two doses of 4-HC were investigated, 0.2 and 2 μM in separate experiments, using biopsies from seven women (aged 27-41) and six women (aged 21-34), respectively. Biopsies from four women (aged 28-38) were used to investigate the effect of rapamycin or AMH only.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Histological analysis of ovarian tissue was undertaken for follicle staging and health assessment. Western blotting and immunostaining were used to assess activation of PI3K signalling by measuring phosphorylation of AKT and phosphorylated FOXO3A staining intensity, respectively.

MAIN RESULTS AND THE ROLE OF CHANCE

Exposure to either dose of 4-HC caused an increase in the proportion of unhealthy primordial (P < 0.0001, both doses) and transitional follicles (P < 0.01 for low dose and P < 0.01 for high dose) compared to vehicle. AMH significantly reduced follicle damage by approximately half in both of the investigated doses of 4-HC (P < 0.0001), while rapamycin had no protective effect on the health of the follicles. Culture with AMH or rapamycin alone had no effect on follicle health. Activation of PI3K signalling following 4-HC exposure was demonstrated by both Western blotting data showing that 4-HC increased in AKT phosphorylation and immunostaining showing increased phosphorylated FOXO3A staining of non-growing oocytes. Treatment with rapamycin reduced the activation of PI3K signalling in experiments with low doses of 4-HC while culture with AMH reduced PI3K activation (both AKT phosphorylation and phosphorylated FOXO3A staining intensity) across both doses investigated.

LIMITATIONS, REASONS FOR CAUTION

These in vitro studies may not replicate in vivo exposures. Furthermore, longer experiment durations are needed to determine whether the effects observed translate into irreparable deficits of ovarian follicles.

WIDER IMPLICATIONS OF THE FINDINGS

These data provide a solid foundation on which to explore the efficacy of AMH in protecting non-growing ovarian follicles from gonadotoxic chemotherapies. Future work will require consideration of the sustained effects of chemotherapy treatment and potential protectants to ensure these agents do not impair the developmental competence of oocytes or lead to the survival of oocytes with accumulated DNA damage, which could have adverse consequences for potential offspring.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by grants from TENOVUS Scotland, the Academy of Medical Sciences (to R.R.), the Medical Research Council (G1100357 to R.A.A., MR/N022556/1 to the MRC Centre for Reproductive Health), and Merck Serono UK (to R.A.A.). R.R., H.L.S., N.S., and E.E.T. declare no conflicts of interest. R.A.A. reports grants and personal fees from Roche Diagnostics and Ferring Pharmaceuticals, and personal fees from IBSA and Merck outside the submitted work.

TRIAL REGISTRATION NUMBER

N/A.

Protective Effect of Glutathione Administration on Ovarian Function in Female Rats with Cyclophosphamide-Induced Ovarian Damage

OBJECTIVES

We investigated the potential of glutathione to protect ovarian function in rats exposed to cyclophosphamide by measuring serum anti-Mullerian hormone (AMH) levels, follicle counts, and related parameters.

DESIGN

Forty-two adult female Sprague-Dawley rats were randomly divided into six groups and treated with various combinations of cyclophosphamide, glutathione, and sodium chloride. On day 21, the rats were anesthetized, and their ovaries were removed for examination.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Histopathological examination, serum AMH concentrations, follicle counts, AMH-positive staining of follicle percentages were analyzed. Statistical analysis was performed using a one-way analysis of variance and Tukey's test, with significance set at p < 0.05. Secondary measures encompassed histopathological examination and percentages of AMH-positive staining of follicles.

RESULTS

Significant differences were observed in follicle counts, AMH-positive follicle parameters, and serum AMH concentrations among the six groups. Group 2 (treated with cyclophosphamide) had the lowest primordial, primary, secondary, and antral follicle counts and the highest atretic count. Group 6, treated with cyclophosphamide and 200 mg/kg glutathione, showed improved follicle counts compared to those in group 2. Reducing the glutathione dose to 100 mg/kg was ineffective.

LIMITATIONS

This was an experimental animal investigation with a comparatively modest sample size. Experimental studies should be conducted to determine the optimal dosage and duration of glutathione therapy. Information gathered from an experimental animal model may not yield precisely similar outcomes in humans; therefore, additional investigations are necessary to examine the impact of glutathione on women experiencing POI.

CONCLUSIONS

The anti-oxidative protective effect of directly administered glutathione was demonstrated for the first time. Low-dose glutathione was ineffective, whereas a high dose yielded significant ovarian protection against cyclophosphamide. Our findings provide valuable insights for supplementing clinical trials on the protective effects of glutathione against ovarian damage.

Cyclophosphamide reduces gene transcriptional activity and embryo in vitro development by inhibiting NF-κB expression through decreasing AcH4K12

Cyclophosphamide (CTX), a widely used chemotherapeutic agent for cancer treatment, has been associated with long-term toxicity and detrimental effects on oocytes and ovaries, resulting in female reproductive dysfunction. This study aimed to investigate the potential impact of CTX on in vitro maturation (IVM) injury of porcine oocytes and subsequent embryonic development, as well as its effects on epigenetic modification and gene activation during early embryonic development. The results demonstrated that CTX treatment caused aberrant spindle structure and mitochondrial dysfunction during oocyte maturation, inducing DNA damage and early apoptosis, which consequently disrupted meiotic maturation. Indeed, CTX significantly reduced the in vitro developmental capacity of porcine embryos, and induced DNA damage and apoptosis in in vitro fertilization (IVF) blastocysts. Importantly, CTX induced abnormal histone modification of AcH4K12 in early porcine embryos. Moreover, addition of LBH589 before zygotic genome activation (ZGA) effectively increased AcH4K12 levels and restored the protein expression of NF-κB, which can effectively enhance the in vitro developmental potential of IVF embryos. The DNA damage and apoptosis induced by CTX compromised the quality of the blastocysts, which were recovered by supplementation with LBH589. This restoration was accompanied by down-regulation of BAX mRNA expression and up-regulation of BCL2, POU5F1, SOX2 and SOD1 mRNA expression. These findings indicated that CTX caused abnormal histone modification of AcH4K12 in early porcine embryos and reduced the protein expression of NF-κB, a key regulator of early embryo development, which may block subsequent ZGA processes.

The Dominant Mechanism of Cyclophosphamide-Induced Damage to Ovarian Reserve: Premature Activation or Apoptosis of Primordial Follicles?

Cyclophosphamide (CPM), a part of most cancer treatment regimens, has demonstrated high gonadal toxicity in females. Initially, CPM is believed to damage the ovarian reserve by premature activation of primordial follicles, for the fact that facing CPM damage, primordial oocytes show the activation of PTEN/PI3K/AKT pathways, accompanied by accelerated activation of follicle developmental waves. Meanwhile, primordial follicles are dormant and not considered the target of CPM. However, many researchers have found DNA DSBs and apoptosis within primordial oocytes under CPM-induced ovarian damage instead of premature accelerated activation. A stricter surveillance system of DNA damage is also thought to be in primordial oocytes. So far, the apoptotic death mechanism is considered well-proved, but the premature activation theory is controversial and unacceptable. The connection between the upregulation of PTEN/PI3K/AKT pathways and DNA DSBs and apoptosis within primordial oocytes is also unclear. This review aims to highlight the flaw and/or support of the disputed premature activation theory and the apoptosis mechanism to identify the underlying mechanism of CPM's injury on ovarian reserve, which is crucial to facilitate the discovery and development of effective ovarian protectants. Ultimately, this review finds no good evidence for follicle activation and strong consistent evidence for apoptosis.

Molecular Mechanisms Determining Mammalian Oocyte Quality with the Treatment of Cancer Therapy

Cancer is a global public health issue and remains one of the leading causes of death in the United States (Siegel et al. CA Cancer J Clin. 72:7-33, 2022). It is estimated in the US in 2022, about 935,000 new cases of cancer will be diagnosed in women, and the probability of developing invasive cancer is 5.8% for females younger than 50 years old (Siegel et al. CA Cancer J Clin. 72:7-33, 2022). However, advances in screening programs, diagnostic methods, and therapeutic options have greatly increased the five-year survival rate in reproductive-age women with a variety of cancers. Given the clinical consequences of gonadotoxic cancer therapies, young, female cancer survivors may face compromised fertility, premature ovarian insufficiency, early-onset menopause, and endocrine dysregulation (Bedoschi et al. Future Oncol. 12:2333-44, 2016). Gonadotoxic side effects may include decreased oocyte quality within surviving follicles, loss of ovarian follicles, and impaired ovarian function. In reproductive-age women, oocyte quality is an important element for successful clinical pregnancies and healthy offspring as poor-quality oocytes may be a cause of infertility (McClam et al. Biol Reprod. 106:328-37, 2022; Marteil et al. Reprod Biol. 9:203-24, 2009; Krisher. J Anim Sci. 82: E14-E23, 2004). Thus, it is critical to determine the quantity and quality of surviving follicles in the ovary after cancer treatment and to assess oocyte quality within those surviving follicles as these are markers for determining the capacity for ovarian function restoration and future fertility, especially for young cancer survivors (Xu et al. Nat Med. 17:1562-3, 2011). The long-term effects of cancer therapeutics on oocyte quality are influenced by factors including, but not limited to, individual patient characteristics (e.g. age, health history, comorbidities, etc.), disease type, or treatment regimen (Marci et al. Reprod Biol Endocrinol. 16:1-112, 2018). These effects may translate clinically into an impaired production of viable oocytes and compromised fertility (Garutti et al. ESMO Open. 6:100276, 2021).

The Role of Cellular Senescence in Cyclophosphamide-Induced Primary Ovarian Insufficiency

Young female cancer patients can develop chemotherapy-induced primary ovarian insufficiency (POI). Cyclophosphamide (Cy) is one of the most widely used chemotherapies and has the highest risk of damaging the ovaries. Recent studies elucidated the pivotal roles of cellular senescence, which is characterized by permanent cell growth arrest, in the pathologies of various diseases. Moreover, several promising senolytics, including dasatinib and quercetin (DQ), which remove senescent cells, are being developed. In the present study, we investigated whether cellular senescence is involved in Cy-induced POI and whether DQ treatment rescues Cy-induced ovarian damage. Expression of the cellular senescence markers p16, p21, p53, and γH2AX was upregulated in granulosa cells of POI mice and in human granulosa cells treated with Cy, which was abrogated by DQ treatment. The administration of Cy decreased the numbers of primordial and primary follicles, with a concomitant increase in the ratio of growing to dormant follicles, which was partially rescued by DQ. Moreover, DQ treatment significantly improved the response to ovulation induction and fertility in POI mice by extending reproductive life. Thus, cellular senescence plays critical roles in Cy-induced POI, and targeting senescent cells with senolytics, such as DQ, might be a promising strategy to protect against Cy-induced ovarian damage.

The effect of L-carnitine on oocyte mitochondrial health and biomarkers on cyclophosphamide chemotherapy drug in mice

Improving oocyte competence during chemotherapy is widely known as a contributing factor to increasing the probability of fertility. Additionally, the role of cumulus cells in oocyte quality is of utmost importance. Therefore, this study was designed to simultaneously probe into the relative gene expression of oocytes and cumulus cells as biomarkers of oocyte quality with cyclophosphamide and L-carnitine treatment. A total of 60 adult NMRI mice were divided into four groups: control, L-carnitine (LC), cyclophosphamide (CP), and cyclophosphamide+L-carnitine (CP+LC). The relative mRNA expression levels of oocyte quality genes including growth differentiation factor 9 (Gdf9), hyaluronan synthase 2 (Has2), and mitochondrial sirtuin 3 (Sirt3) in oocytes, and genes involved in bilateral communication between cumulus cells and between the oocyte and its neighboring cumulus cells including connexin 37 (Cx37) and connexin 43 (Cx43) were detected by Real-time-PCR. DCFH-DA staining analyzed the level of intracellular ROS in oocytes. Under the influence of L-carnitine, Gdf9, Has2, Cx43, and Cx37 were significantly up-regulated (p ≤ 0.05). However, cyclophosphamide considerably reduced the expression of all these genes (p ≤ 0.05). The expression of the Sirt3 gene in the CP group increased significantly compared to the other groups (p ≤ 0.05). Analysis of fluorescent images revealed that the level of intracellular ROS in the cyclophosphamide group was significantly increased compared to the other groups (p ≤ 0.05), while it plummeted in the L-carnitine group (p ≤ 0.05). L-carnitine as an antioxidant can reduce the destructive effects of cyclophosphamide and enhance bilateral communications between oocytes and cumulus cells, and it may ultimately lead to an increase in the fertility rate.

Protective potential of pterostilbene against cyclophosphamide-induced nephrotoxicity and cystitis in rats

PURPOSE

Cyclophosphamide (CYP) is an antitumor drug. However, in addition to its antitumor affect, CYP can also lead to nephrotoxicity and hemorrhagic cystitis. The purpose of this study was to investigate the potential protective effects of Pterostilbene (Pte), a natural antioxidant as a resveratrol analog against CYP-induced nephrotoxicity and cystitis in rats.

METHODS

Twenty-one male Sprague Dawley rats were divided into 3 equal groups. The control group and the CYP group (CYPG) received 1 ml/kg sunflower oil per day, and the CYP + Pte group (CYP + PteG) 40 mg/kg per day Pte dissolved in sunflower oil once a day via the oral route for 14 days. In addition, on day 9 of the experiment, CYPG and CYP + PteG received a single dose of 200 mg/kg CYP dissolved in saline solution, while the control group received a single dose of 10 ml/kg saline solution, via the intraperitoneal route. Bladder and kidney tissues were collected for histological and biochemical evaluations.

RESULTS

Pte was observed to reduce CYP-derived increases in malondialdehyde level, total oxidant status (TOS), the oxidative stress index (OSI), and apoptosis in kidney tissues and to cause an increase in superoxide dismutase levels. It also reduced CYP-derived increases in TOS, OSI, and apoptosis in bladder tissue. Moreover, Pte also ameliorated histopathological findings associated with CYP-induced tissue damage in both the kidney and bladder.

CONCLUSION

Our study findings show that Pte may exhibit a protective effect against CYP-induced nephrotoxicity and cystitis.

CHEK2 signaling is the key regulator of oocyte survival after chemotherapy

Cancer treatments can damage the ovarian follicle reserve, leading to primary ovarian insufficiency and infertility among survivors. Checkpoint kinase 2 (CHEK2) deficiency prevents elimination of oocytes in primordial follicles in female mice exposed to radiation and preserves their ovarian function and fertility. Here, we demonstrate that CHEK2 also coordinates the elimination of oocytes after exposure to standard-of-care chemotherapy drugs. CHEK2 activates two downstream targets-TAp63 and p53-which direct oocyte elimination. CHEK2 knockout or pharmacological inhibition preserved ovarian follicle reserve after radiation and chemotherapy. However, the lack of specificity for CHEK2 among available inhibitors limits their potential for clinical development. These findings demonstrate that CHEK2 is a master regulator of the ovarian cellular response to damage caused by radiation and chemotherapy and warrant the development of selective inhibitors specific to CHEK2 as a potential avenue for ovario-protective treatments.

Chemotherapy-induced ovarian damage and protective strategies

More than 9.2 million women worldwide suffer from cancer, and about 5% of them are at reproductive age. Chemotherapy-induced impairment of fertility affects the quality of life of these women. Several chemotherapeutic agents have been proven to cause apoptosis and autophagy by inducing DNA damage and cellular stress. Injuries to the ovarian stroma and micro-vessel network are also considered as pivotal factors resulting in ovarian dysfunction induced by chemotherapeutic agents. Primordial follicle pool over-activation may also be the mechanism inducing damage to the ovarian reserve. Although many studies have explored the mechanisms involved in chemotherapy-induced reproductive toxicity, the exact molecular mechanisms have not been elucidated. It is essential to understand the mechanisms involved in ovarian damage, in order to develop potential protective treatments to preserve fertility. In this article, we reviewed the current knowledge on the mechanism of chemotherapy-induced ovarian damage and possible protective strategies that prevent the ovary from such damages.

Network analysis and experimental approach to investigate the potential therapeutic mechanism of zishen yutai pills on premature ovarian insufficiency

Background

As society continues to develop, women are more at risk of gonadotoxic substance exposure. Consequently, the incidence of premature ovarian insufficiency (POI) has increased significantly in the past decades. Hormone replacement therapy (HRT) is recommended as the standard treatment to relieve hypoestrogenic symptoms; however, its potential side effects and contraindications have drawn widespread controversy and concern. As such, the Chinese medicine Zishen Yutai Pill (ZSYTP) commonly used for treating miscarriage and menoxenia, is a highly promising alternative drug candidate against POI, however its therapeutic mechanism has not been completely elucidated.

Objective

To systematically analyze the potential therapeutic targets of ZSYTP on POI, we combined network pharmacology analysis and molecular docking to predict critical target genes, with experimental validation on POI murine models.

Methods

The active compounds of ZSYTP were collected from three online databases, and the candidate targets were predicted based on the chemical structure. The POI-related targets were obtained from four databases. A PPI network was constructed to find the key target genes between ZSYTP and POI, while GO and KEGG enrichment analyses were employed to study the mechanism of ZSYTP against POI. The binding capability of the key co-targets with active components was examined by molecular docking. We used a cyclophosphamide (CTX)-inducible POI mouse model to verify our predictions by histopathological observation, immunohistochemical staining (caspase-3, TUNEL assay), hormone determination (FSH, AMH) and ribonucleic acid sequencing (RNA Seq). Progynova was also used to study the difference between ZSYTP and HRT.

Result

We identified 21 target genes as the hub between ZSYTP and POI. The GO and KEGG analyses revealed that the molecular mechanism of ZSYTP against POI were mainly based on the regulation of gene and protein expression. A variety of signaling pathways may be involved in the treatment of ZSYTP against POI, especially PI3K-AKT, HIF-1 and the AGE-RAGE cascades. Docking simulation showed that G1, C1, SR5, and F1 had relatively lower binding energy. In vivo, ZSYTP significantly reversed CTX-induced ovarian damage in follicle number, hormone level and apoptosis, with an overall improved therapeutic effect compared to Progynova. Results from RNA-Seq revealed that the PI3K-AKT, Hippo, AGE-RAGE, and Rap1 signaling pathways and regulation of inflammation, immune response, and lipid metabolism may mediate the protective effects of ZSYTP against POI, which is different than Progynova's mechanism of action.

Conclusions

Collectively, this study indicates that ZSYTP could be a highly promising alternative as a non-HRT-based therapy for POI. Its mechanism involves multiple signaling pathways, alleviating ovarian apoptosis and recovering AMH and FSH level. However, the discrepancy between different research techniques highlight the necessity of further experimental verification from other aspects such as translation and posttranslational modification.

Investigation of the Mechanisms and Experimental Verification of Yulin Formula in the Treatment of Diminished Ovarian Reserve via Network Pharmacology

Purpose

The aim of this study is to examine, using network pharmacology analysis and experimental validation, the pharmacological processes by which Yulin Formula (YLF) reduces cyclophosphamide-induced diminished ovarian reserve (DOR).

Methods

First, information about the active components, associated targets, and related genes of YLF and DOR was gathered from open-access databases. The primary targets and pathways of YLF to reduce DOR were predicted using studies of functional enrichment from the Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), and Protein-Protein Interaction (PPI) networks. Second, we built a cyclophosphamide-induced diminished ovarian reserve (DOR) rat model to verify the primary target proteins implicated in the predicted signaling pathway to explore the mechanism of improve ovarian function of YLF.

Results

98 targets met the targets of the 82 active ingredients in YLF and DOR after searching the intersection of the active ingredient targets and DOR targets. Fourteen targets, including AKT and Caspase-3 among others, were hub targets, according to the PPI network study. The PI3K/AKT pathway was revealed to be enriched by numerous targets by the GO and KEGG enrichment studies, and it was used as a target for in vivo validation. Animal studies showed that YLF administration not only reduced the number of atretic follicles, the proportion of TUNEL-positive ovarian cells, the rate of apoptosis of granulosa cells (GCs) and the proportion of abnormal mitochondria in DOR rats, but also reversed the high expression of Caspase-3, Caspase-9, BAX, cytochrome C, PI3K and P-AKT, improving the ovarian reserve in cyclophosphamide (CTX)-induced DOR rats.

Conclusion

Our research results predicted the active ingredients and potential targets of YLF-interfering DOR by an integrated network pharmacology approach, and experimentally validated some key target proteins participated in the predicted signaling pathway. A more comprehensive understanding of the pharmacological mechanism of YLF for DOR treatment was obtained.

Tamoxifen decreases ovarian toxicity without compromising cancer treatment in a rat model of mammary cancer

BACKGROUND

Premenopausal women diagnosed with breast cancer often face aggressive chemotherapy resulting in infertility. Tamoxifen (TAM) is a selective estrogen receptor modulator that was previously suggested as a protective agent against chemotherapy-induced ovarian failure. In the current study, we examined mechanisms of the protective action of TAM in the ovaries of tumor-bearing rats treated with the chemotherapy drug cyclophosphamide (CPA).

RESULTS

TAM prevented CPA-induced loss of ovarian follicular reserves. The protective TAM effect in the rat ovary partially resulted from decreased apoptosis. In addition, transcriptomic and proteomic screening also implicated the importance of DNA repair pathways as well as cell adhesion and extracellular matrix remodeling in the protective ovarian actions of TAM.

CONCLUSIONS

Tamoxifen shielded the ovary from the side effects of chemotherapy without lessening the tumoricidal actions of mammary cancer treatment.

Ovarian scaffolds promoted mouse ovary recovery from cyclophosphamide damage

There is growing evidence to suggest that scaffold of tissue can promote the tissue reparation. In this study, we investigate the effects of ovarian scaffolds on the reparation of cyclophosphamide (CPA) damaged mice ovaries. The mice were first administered with CPA, was then either transplanted an ovarian scaffold into each ovarian bursa for the experimental group (EG) or underwent sham surgery as the control (CG). To evaluate the extent of ovarian damage caused by CPA, a third group which did not undergo any treatment was included for the normal control (NG). Their ovaries were harvested for examination at day 30, 60, and 90 post CPA injection. We found that in EG, the number of all types of follicles in the ovaries remained almost the same throughout. The numbers of follicles were not significantly different from CG, except at day 60, where in CG the numbers of each type of follicle decreased to basal levels. The decrease in the number of ovarian follicles at day 60 in CG was mirrored by the significant increase in the number of apoptotic granulosa cells in the follicles, and was corroborated further by the basal levels of serum estradiol. Furthermore, we observed a significant decrease in collagen composition preceded by macrophage polarization, and elevation of inflammatory cytokine expression in the ovaries of the EG compared to the CG at day 60. We concluded that ovarian scaffolds can effectively protect primordial follicles from CPA-damage and promote the reparation of CPA-damaged ovaries. This research establishes a proof of concept for the future treatment of chemo-damaged ovaries.

Chemotherapy induced oxidative stress in the ovary: drug-dependent mechanisms and potential interventions†

Cancer incidence and relative survival are expected to increase over the next few decades. With the majority of patients receiving combinatorial chemotherapy, an increasing proportion of patients experience long-term side effects from treatment-including reproductive disorders and infertility. A limited number of studies have examined mechanisms of single-agent chemotherapy-induced gonadotoxicity, with chemotherapy-induced oxidative stress being implicated in the loss of reproductive functions. Current methods of female fertility preservation are costly, invasive, only moderately successful, and seldom presented to cancer patients. The potential of antioxidants to alleviate chemotherapy has been overlooked at a time when it is becoming increasingly important to develop strategies to protect reproductive functions during chemotherapy. This review will summarize the importance of reactive oxygen species homeostasis in reproduction, chemotherapy-induced mitochondrial dysfunction in oocytes, chemotherapy-induced oxidative stress, and several promising natural adjuvants.

The future of fertility preservation for women treated with chemotherapy

Cytotoxic chemotherapies have been a mainstay of cancer treatment, but are associated with numerous systemic adverse effects, including impacts to fertility and endocrine health. Irreversible ovarian damage and follicle depletion are side-effects of chemotherapy that can lead to infertility and premature menopause, both being major concerns of young cancer patients. Notably, many women will proceed with fertility preservation, but unfortunately existing strategies don't entirely solve the problem. Most significantly, oocyte and embryo freezing do not prevent cancer treatment-induced ovarian damage from occurring, which may result in the impairment of long-term hormone production. Unfortunately, loss of endogenous endocrine function is not fully restored by hormone replacement therapy. Additionally, while GnRH agonists are standard care for patients receiving alkylating chemotherapy to lessen the risk of premature menopause, their efficacy is incomplete. The lack of more broadly effective options stems, in part, from our poor understanding of how different treatments damage the ovary. Here, we summarise the impacts of two commonly utilised chemotherapies - cyclophosphamide and cisplatin - on ovarian function and fertility, and discuss the mechanisms underpinning this damage. Additionally, we critically analyse current research avenues in the development of novel fertility preservation strategies, with a focus on fertoprotective agents.

Chemotherapy and female fertility

Chemotherapy to treat cancer is usually responsible for early ovarian follicle depletion. Ovarian damage induced by cancer treatments frequently results in infertility in surviving patients of childbearing age. Several fertility preservation techniques have been developed. Nowadays, oocyte or embryo cryopreservation with or without ovarian stimulation and cryopreservation of the ovarian cortex are the most commonly used. However, these methods may be difficult to implement in some situations, and subsequent use of the cryopreserved germ cells remains uncertain, with no guarantee of pregnancy. Improved knowledge of the molecular mechanisms and signaling pathways involved in chemotherapy-induced ovarian damage is therefore necessary, to develop new strategies for fertility preservation. The effects of various chemotherapies have been studied in animal models or in vitro on ovarian cultures, suggesting various mechanisms of gonadotoxicity. Today the challenge is to develop molecules and techniques to limit the negative impact of chemotherapy on the ovaries, using experimental models, especially in animals. In this review, the various theories concerning ovarian damage induced by chemotherapy will be reviewed and emerging approaches for ovarian protection will be explained.

Identification of royal jelly as a potential new drug to protect the ovarian reserve and uterus against cyclophosphamide in rats

OBJECTIVE

The aim of this study was to investigate the effect of royal jelly (RJ), a powerful natural antioxidant, on cyclophosphamide-induced ovarian damage.

METHODS

Thirty-two Wistar albino rats were divided into four groups. Oral treatment was administered to all rats for 16 days after a single intraperitoneal injection. The control group received intraperitoneal and oral saline; the RJ group received intraperitoneal saline and 100 mg/kg/day oral RJ; the cyclophosphamide group received intraperitoneal 100 mg/kg cyclophosphamide and oral saline; and the treatment group received intraperitoneal 100 mg/kg cyclophosphamide and 100 mg/kg/day oral RJ. The groups were compared in terms of ovarian reserve tests and histopathological changes in the ovary and uterus.

RESULTS

All follicle counts were higher in the treatment group than in the cyclophosphamide group. The increase in the number of preantral follicles (p=0.001) and the decrease in the number of atretic follicles (p=0.004) were statistically significant. RJ treatment significantly improved follicular degeneration and cortical fibrosis in the ovary and epithelial and gland degeneration in the uterus due to cyclophosphamide toxicity.

CONCLUSION

According to these results, RJ reduces cyclophosphamide-related ovarian and endometrial damage in rats. For this reason, it should be further investigated to determine its effects on reproductive function.

When to cryopreserve ovarian tissue: Determining the effects of chemotherapy on the ovarian reserve by studying follicular density and apoptosis

OBJECTIVES

Patients scheduled to receive chemotherapy should be counselled on fertility preservation. Known gonadotoxic chemotherapies such as alkylating agents have a high risk of altering ovarian reserve. In some cases, the urgency of treatment requires the use of chemotherapy before fertility preservation, which will be carried out at a later stage. Usually the ovarian tissue is cryopreserved. The aim of our study is to investigate the impact of chemotherapies on follicular density and the apoptosis of reserve follicles.

METHODS

We included 140 patients: 63 patients, mean age 18.8 years, were included in the group "no chemotherapy" (group A) and 77 patients, mean age 17.1 years, in the group "received chemotherapy before ovarian conservation" (group B). None of the patients had had pelvic radiotherapy prior to ovarian cryopreservation. The histological parameters studied were follicular density and the presence of malignant cells. We selected 12 patients from group A and 15 patients from group B, comparable in age and pathology, for whom we evaluated follicle apoptosis by immunostaining cleaved caspase-3.

RESULTS

We demonstrated an inverse relationship between follicular density and age (p < 0.0001), as well as a lack of effect of chemotherapy on follicular density (p = 0.87). We showed the impact of various chemotherapies, especially with alkylating agents, on the apoptosis of ovarian follicles (p < 0.0001). Three patients had ovarian tissue infiltration, two of which were malignant.

CONCLUSION

This work underlines the fact that conservation of ovarian tissue after chemotherapy remains possible.

Role of apoptosis and autophagy in ovarian follicle pool decline in children and women diagnosed with benign or malignant extra-ovarian conditions

STUDY QUESTION

Which biological mechanisms are responsible for physiological ovarian reserve decline owing to aging, or pathological follicle depletion triggered by inflammation or a pro-oxidant environment throughout a woman's lifetime?

SUMMARY ANSWER

Ovarian follicle pool size is modulated by both apoptosis and autophagy, the first responsible for its physiological decline over time and increasing in the event of prior chemotherapy in children, and the latter playing a major role in physiological ovarian follicle pool diminution before puberty.

WHAT IS KNOWN ALREADY

Among the different pathways of controlled cell death, apoptosis and autophagy are implicated in follicle loss. Apoptosis participates in eliminating damaged follicles, such as those impaired by chemotherapy (CHT), but its involvement in physiological age-related follicle decline is less well understood. Autophagy has proved crucial in follicle quiescence maintenance in murine models, but its contribution to human follicle pool modulation is still unclear.

STUDY DESIGN, SIZE, DURATION

This retrospective study included 84 patients with benign or malignant extra-ovarian conditions aged between 1 and 35 years, with ovarian tissue stored for histological analyses at the time of cryopreservation (between 2012 and 2021) at a tertiary care center.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Ovarian fragments were used for the following analyses: hematoxylin and eosin staining for follicle count and classification; cleaved caspase-3 immunostaining to identify follicle apoptosis; and microtubule-associated proteins 1A/1B light chain 3B immunolabeling to detect follicle autophagy. Transmission electron microscopy was also carried out to investigate ultrastructural features of oocytes and granulosa cells. All analyses stratified patients by age, menarchal status (premenarchal = 32; postmenarchal = 52), potentially gonadotoxic CHT before cryopreservation (n = 14), presence of endometriosis and use of hormonal treatment.

MAIN RESULTS AND THE ROLE OF CHANCE

Premenarchal patients had a larger follicle pool in terms of total follicle density [mean, range 4979.98 (342.2-21789) versus 918.8 (26.18-3983), P < 0.001], but higher rates of morphologically abnormal [8.52 (0-25.37)% versus 3.54 (0-17.5)%, P < 0.001] and atretic [15.8 (0‒31.85)% versus 10.6 (0-33.33)%, P < 0.01] follicles than postmenarchal subjects. Apoptosis rates did not change with increasing age [27.94 (0-93.2)% in prepubertal subjects and 29.5 (0-100)% in postpubertal subjects], but autophagic follicles were around 10 times more common in premenarchal than postmenarchal subjects [10.21 (0-62.3)% versus 1.34 (0-25)%, P < 0.001], playing a crucial role in age-related follicle decline and elimination of 'abnormal' follicles, that are rarely seen after menarche. The impact of diagnosis and previous CHT varied according to age. In premenarchal patients with previous CHT, significantly more apoptotic [40.22 (0-100)% versus 26.79 (0-87)%, P < 0.05] and fewer abnormal [3.84 (0-10-76)% versus 9.83 (0-25.37)%, P < 0.01] follicles were detected than in subjects with no CHT prior to ovarian tissue cryopreservation, suggesting a direct effect on follicle elimination, especially of those with abnormalities. In postmenarchal subjects with previous CHT, quiescent follicle rates were lower than in patients with no CHT before tissue freezing [71.57 (0-100)% versus 85.89 (50-100)%, P < 0.05], suggesting accelerated follicle activation and growth. Moreover, increased autophagic activity was observed in the event of a cancer diagnosis compared to benign conditions after puberty [26.27 (0-100)% versus 9.48 (0-29.41)%, respectively, P < 0.05].

LIMITATIONS, REASONS FOR CAUTION

The impact of specific CHT protocols could not be investigated since the group of patients with previous CHT was highly heterogeneous.

WIDER IMPLICATIONS OF THE FINDINGS

This study yields a deeper understanding of regulation of the follicle pool decline, showing for the first time that both apoptosis and autophagy pathways are involved in physiological follicle depletion, the latter being crucial before puberty. Moreover, our data showed a different response to non-physiological damage according to age, with higher apoptosis rates only in premenarchal subjects with previous CHT, confirming that this pathway is activated by drugs known to induce DNA damage in oocytes, such as alkylating agents, but not by cancer itself.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by grants from the Fonds National de la Recherche Scientifique de Belgique (F.R.S.-FNRS/FRIA FC29657 awarded to L.C., CDR J.0063.20 and grant 5/4/150/5 awarded to M.M.D.), grants from the Fondation contre le Cancer (grant 2018-042 awarded to A.Ca.), the Fondazione Comunitaria del Varesotto and Provincia di Varese ('Amalia Griffini' Fellowship in Gynecology and Obstetrics awarded to A.Ce.), Fonds Spéciaux de Recherche, Fondation St Luc and donations from the Ferrero family. The authors have no competing interests to declare.

TRIAL REGISTRAION NUMBER

N/A.

Ginger's Antiapoptotic and Antioxidant Effects on Ovaries of Cyclophosphamide-therapied Rats

BACKGROUND

In the recent decade, there has been increasing interest in preventing ovarian toxicity after chemotherapy exposure. It has been documented that ginger (Zingiber officinale) might normalize the hormonal balance and control the menstrual cycle..

OBJECTIVE

This study has analyzed whether ginger extract protects against cyclophosphamide (CP)-induced ovarian failure in rats.

METHODS

Rats were distributed into four groups consisting of vehicle, CP, ginger, and CP + ginger. At the end of the treatment, all rats were killed under anesthesia to obtain ovarian tissues and blood samples for histological, molecular, and biochemical experiments.

RESULTS

Our results indicated that ginger improves CP-caused histological changes in ovarian tissues and significantly restores serum hormonal abnormalities. Ginger also showed unique antioxidant, anti-inflammatory, and antiapoptotic properties in the ovarian tissues of CP-induced rats. Further, our findings indicated that ginger might activate the Nrf2 and SIRT and inhibit the PI3K/AKT pathway in the ovaries of CP-treated rats. In conclusion, ginger was found to protect against CP-caused ovarian toxicity in rats.

CONCLUSION

The protective impacts of ginger may mediate, at least partly, by alleviating the oxidant state, inhibiting pro-inflammatory conditions, and exhibiting antiapoptotic activities.

TAp63 determines the fate of oocytes against DNA damage

Cyclophosphamide and doxorubicin lead to premature ovarian insufficiency as an off-target effect. However, their oocyte death pathway has been debated. Here, we clarified the precise mechanism of ovarian depletion induced by cyclophosphamide and doxorubicin. Dormant oocytes instead of activated oocytes with high PI3K activity were more sensitive to cyclophosphamide. Checkpoint kinase 2 (CHK2) inhibitor rather than GNF2 protected oocytes from cyclophosphamide and doxorubicin, as cyclophosphamide up-regulated p-CHK2 and depleted primordial follicles in Abl1 knockout mice. Contrary to previous reports, TAp63 is pivotal in cyclophosphamide and doxorubicin-induced oocyte death. Oocyte-specific Trp63 knockout mice prevented primordial follicle loss and maintained reproductive function from cyclophosphamide and doxorubicin, indicated by undetectable levels of BAX and cPARP. Here, we demonstrated that TAp63 is fundamental in determining the signaling of oocyte death against DNA damage. This study establishes the role of TAp63 as a target molecule of adjuvant therapies to protect the ovarian reserve from different classes of chemotherapy.

BNC1 deficiency-triggered ferroptosis through the NF2-YAP pathway induces primary ovarian insufficiency

Primary ovarian insufficiency (POI) is a clinical syndrome of ovarian dysfunction characterized by premature exhaustion of primordial follicles. POI causes infertility, severe daily life disturbances and long-term health risks. However, the underlying mechanism remains largely unknown. We previously identified a Basonuclin 1 (BNC1) mutation from a large Chinese POI pedigree and found that mice with targeted Bnc1 mutation exhibit symptoms of POI. In this study, we found that BNC1 plays key roles in ovarian reserve and maintaining lipid metabolism and redox homeostasis in oocytes during follicle development. Deficiency of BNC1 results in premature follicular activation and excessive follicular atresia. Mechanistically, BNC1 deficiency triggers oocyte ferroptosis via the NF2-YAP pathway. We demonstrated that pharmacologic inhibition of YAP signaling or ferroptosis significantly rescues Bnc1 mutation-induced POI. These findings uncover a pathologic mechanism of POI based on BNC1 deficiency and suggest YAP and ferroptosis inhibitors as potential therapeutic targets for POI.

Primary ovarian insufficiency (POI) is a clinical syndrome of ovarian dysfunction that results in infertility. Here they show that BCN1 mutation results in premature ovarian follicle activation and atresia through dysregulation of ferroptosis.

Effects of hypoxia-preconditioned HucMSCs on neovascularization and follicle survival in frozen/thawed human ovarian cortex transplanted to immunodeficient mice

Background

The massive loss of follicles in the early stage of ovarian tissue transplantation is considered a significant restriction to the efficacy of ovarian tissue cryopreservation (OTC) and transplantation (OT). The use of mesenchymal stem cells (MSCs) before transplantation of ovarian fragments shortened the hypoxic period and boosted neovascularization. Hypoxia-preconditioned MSCs can enhance the potential of angiogenesis. Can hypoxia-preconditioned human umbilical cord mesenchymal stem cell (HucMSCs) and ovarian tissue co-xenotransplantation improve more neovascularization and subsequently more follicle survival in human ovarian tissue?

Methods

Frozen-thawed cortical pieces from 4 patients were transplanted into the bilateral renal capsule of immune-deficient nude mice without HucMSCs or normoxia/hypoxia-preconditioned HucMSCs. Sixty-four mice were randomly distributed into 4 groups. In each group, the mice were euthanized for blood and/or graft retrieval on post-transplantation days 3 (n = 8) and 7 (n = 8), respectively. Non-grafted frozen-thawed ovarian fragment was taken for non-grafted control. Grafts were histologically processed and analysed for follicle density and atretic follicles by HE, neovascularization by CD34 and CD31 immunohistochemical staining, primordial follicle growth by Ki67 staining, and apoptosis of stromal cell and follicles by immunofluorescence using TUNEL. The ROS and TAC levels of grafted and non-grafted tissue were assessed. We evaluated the protein expression of HIF1α, VEGFA, pAkt, Akt, and GDF9 in grafted and non-grafted ovarian tissue. E2, Prog, AMH, and FSH levels in the plasma of mice were measured after 3 and 7 days of OT.

Results

Hypoxia-preconditioned HucMSCs positively protect the grafted ovarian tissue by significantly decreasing the apoptosis and increasing higher expression of CD31, CD34, and VEGFA for earlier angiogenesis. They are crucial to preserving the resting primordial follicle pool by modulation of follicle death.

Conclusion

This is the first study to demonstrate that co-transplantation of hypoxia-preconditioned HucMSC with ovarian tissue improved earlier vascularization of ovarian grafts in the early post-grafting period, which correlates with increased follicle survival and reduced apoptosis. The HIF1α/VEGFA signal pathways may play an important role in elucidating the mechanisms of action of hypoxia-preconditioned HucMSCs with regard to OT and clinical implementation.

Impact of Co-Administration of N-Acetylcysteine and Vitamin E on Cyclophosphamide-Induced Ovarian Toxicity in Female Rats

Cyclophosphamide is used to treat various types of cancer. However, it can reduce ovarian function and fertility rate. The current study was done to compare the effects of N-acetylcysteine and vitamin E on cyclophosphamide-induced ovarian damage. Thirty-five rats were randomly divided into 5 groups: control (C), cyclophosphamide (CP, 200 mg/kg single dose intraperitoneally), T1 (cyclophosphamide + vitamin E at 200 mg/kg), T2 (cyclophosphamide + 200 mg/kg N-acetylcysteine), and T3 (cyclophosphamide + N-acetylcysteine and vitamin E at 200 mg/kg). The main measurements included total antioxidant capacity (TAC), glutathione peroxidase (GPx), malondialdehyde (MDA), interleukin 8 (IL-8), tumor necrosis factor-α (TNFα), follicle stimulating hormone (FSH), luteinizing hormone (LH), and estrogen (ES). Except for the C and T3 groups, the other groups lost weight. A significantly lower concentration of MDA was observed in the T3 group. However, TAC was substantially increased compared to the other groups. The level of GPx in the S group was significantly reduced compared to all groups. Proinflammatory markers (IL-8 and TNFα) reached their lowest serum level in the T3 group, with a statistically significant difference compared to that of the S group. In addition, there were no significant differences in the means of primary, secondary, and graph and atretic follicles between the T3 and C group. On the other hand, a decrease in FSH and LH was observed while an increase in ES was seen in the T3 group compared to the S group. This study revealed that N-acetylcysteine and vitamin E coadministration could significantly decrease the side effects of cyclophosphamide, especially in ovarian tissue.

Protective Effects of Antioxidants on Cyclophosphamide-Induced Ovarian Toxicity

The most common limitation of anticancer chemotherapy is the injury to normal cells. Cyclophosphamide, which is one of the most widely used alkylating agents, can cause premature ovarian insufficiency and infertility since the ovarian follicles are extremely sensitive to their effects. Although little information is available about the pathogenic mechanism of cyclophosphamide-induced ovarian damage, its toxicity is attributed to oxidative stress, inflammation, and apoptosis. The use of compounds with antioxidant and cytoprotective properties to protect ovarian function from deleterious effects during chemotherapy would be a significant advantage. Thus, this article reviews the mechanism by which cyclophosphamide exerts its toxic effects on the different cellular components of the ovary, and describes 24 cytoprotective compounds used to ameliorate cyclophosphamide-induced ovarian injury and their possible mechanisms of action. Understanding these mechanisms is essential for the development of efficient and targeted pharmacological complementary therapies that could protect and prolong female fertility.

Impact of imatinib administration on the mouse ovarian follicle count and levels of intra-ovarian proteins related to follicular quality

Objective

The impact of imatinib, a tyrosine kinase inhibitor, on ovarian follicles and several proteins related to follicular function and apoptosis was investigated in mice.

Methods

Saline, cyclophosphamide (Cp; 50 or 75 mg/kg), or imatinib (7.5 or 15 mg/kg) was injected once intraperitoneally into female B6D2F1 mice (18 mice in each group). In multiple ovarian sections, the number of various types of follicles and the proportion of good-quality (G1) follicles were counted. The levels of six proteins (anti-Müllerian hormone [AMH], BCL-xL, BAX, acid sphingomyelinase [A-SMase], caspase-3, and α-smooth muscle actin [α-SMA]) within the whole ovaries were quantified using Western blots.

Results

Compared to the saline group, a significant reduction of the primordial follicle count was observed in the group treated with imatinib 7.5 and 15 mg/kg, as well as in the group treated with Cp 75 mg/kg. Administration of Cp significantly decreased the proportion of G1 primordial follicles, but administration of imatinib did not. No differences in the AMH, anti-apoptotic BCLX-L, pro-apoptotic BAX, and A-SMase levels in the ovarian tissues were observed among the five groups. However, caspase-3 and α-SMA levels were significantly higher in the imatinib and Cp groups than in the saline group.

Conclusion

The administration of imatinib to mice significantly reduced the primordial follicle count and increased the protein levels of caspase-3 and α-SMA. Our findings suggest that imatinib potentially exerts ovarian toxicity via apoptotic processes, similarly to Cp.

Sesamol protects the function and structure of rat ovaries against side effects of cyclophosphamide by decreasing oxidative stress and apoptosis

AIM

Chemotherapy with cyclophosphamide can damage ovaries and cause infertility in girls and women. Sesamol is a phenolic antioxidant that can protect various organs from damage. The purpose of this study was to evaluate the effects of sesamol on protecting the function and structure of rat ovaries against the side effects of a chemotherapy model with cyclophosphamide.

METHODS

Twenty-four adult female Wistar rats were randomly divided into three groups: (1) normal group, without any treatment, (2) control group, immediately after receiving cyclophosphamide, 0.5% dimethyl sulfoxide (DMSO) as the solvent of sesamol was intraperitoneally injected for 14 consecutive days, (3) sesamol group, immediately after receiving cyclophosphamide, 50 mg/kg sesamol was intraperitoneally injected for 14 consecutive days. Four weeks after the last injection, superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels in the ovary, anti-Mullerian hormone (AMH) levels in the serum, number of ovarian follicles in different stages, and expression of proteins growth differentiation factor-9 (GDF-9), Bcl-2, and Bax in the ovary were evaluated.

RESULTS

The results of SOD activity and MDA levels in the ovary, AMH levels in the serum, number of ovarian follicles in different stages, and expression of proteins GDF9, Bcl-2, and Bax in the ovary were significantly more favorable in the sesamol group than the control group.

CONCLUSIONS

The results suggest that sesamol may protect function and structure in the rat ovaries against side effects of the chemotherapy model with cyclophosphamide by decreasing oxidative stress and apoptosis in the ovary.

Evidence of cancer therapy-induced chronic inflammation in the ovary across multiple species: A potential cause of persistent tissue damage and follicle depletion

Chemotherapy and radiation treatments are known for deleterious effects on the ovary, which can result in prolonged recovery time before ovarian function resumes, including follicular growth after completion of these therapies. To better understand the protracted ovarian dysfunctions after chemotherapy and radiotherapy, we designed a comprehensive study to investigate the underlying mechanisms involved in chronic ovarian damage that prevent follicular development and/or to induce persistent follicle loss. Blood and ovarian samples were collected from reproductive age women, rhesus macaques, and mice after completion of chemotherapy and/or radiotherapy and from age-matched patients and animals without chemotherapy agent or radiation exposure to serve as controls. Serum levels of anti-Müllerian hormone and proinflammatory cytokines, monocyte chemoattractant protein 1 and IL6, were measured. Ovarian tissue was assessed for histopathology and inflammatory cell infiltration, e.g., macrophages and neutrophils, by immuohistochemistry. Serum anti-Müllerian hormone concentrations were lower, whereas proinflammatory cytokine concentrations were higher, in patients and rhesus macaques at ~1 year post-chemotherapy agent and/or radiation exposure compared with controls. The number of primordial follicles reduced in the mouse ovary > 5 weeks after a single injection of cyclophosphamide. Macrophage infiltration was observed in the ovarian cortex of humans and animals. These data suggest that chronic inflammation induced by chemotherapy agents and/or radiation treatment may be associated with persistent ovarian tissue damage, follicle depletion, and functional decline. Interventions that dampen the overactivated inflammatory response may further protect the ovary after completion of chemotherapy and radiotherapy to maintain follicle viability and support continued follicular development in female patients.

Efficacy of Bushen Culuan decoction on ovarian follicle and follicular granulosa cells in mice with premature ovarian insufficiency induced by tripterygium wilfordii polyglycoside

OBJECTIVE

To investigate the protective efficacy of Bushen Culuan decoction (BCD) on ovarian follicle and follicular granulosa cells in mice with premature ovarian insufficiency (POI) induced by tripterygium wilfordii polyglycoside, and to study the potential mechanism underlying the action.

METHODS

Eighty female Balb/c mice were randomly divided into 4 groups (n = 20 each): blank group, model group, Bushen Culuan decoction intervening group (BCD group) and estradiol valerate intervening group (EV group). In the first 14 model establishing d, mice in model group, BCD group and EV group were under Tripterygium wilfordii polyglycoside (TWP) gavage to establish POI models. In the 14-day therapeutic stage, mice in BCD group were taken BCD 18.35 mg·kg-1d-1, mice in EV group were taken EV solution 0.15 mg·kg-1d-1, while mice in blank group and model group were taken normal saline. When the mice accomplished therapy, whole blood was collected for serum hormone including follicle stimulating hormone (FSH), luteal hormone (LH), estradiol (E2), antimullerian hormone (AMH) levels and vascular endothelial growth factor (VEGF), bone morphogenetic protein-7 (BMP-7) measurement. Ovarian tissues were harvested for morphologic observation, follicle counting, ovarian follicular graulosa cell apoptosis test and testing BMP-7 and caspase-3 expressions.

RESULTS

The body weights of the mice kept growing stably in the process expect in TWP intervening stage. Compared with model group, BCD group had significantly higher ovarian index, serum E2, AMH, VEGF, BMP-7 levels and significantly lower FSH level (P < 0.05). Meanwhile the VEGF level in BCD group was higher than in EV group (P < 0.05). Compared with model group, the histopathological damage and GCs apoptosis were mitigated; developing follicle counting, BMP-7 expression were up-regulated, and caspase-3 expression was downregulated in BCD groups (P < 0.05).

CONCLUSION

BCD treatment could attenuate pathological process in POI ovaries, suppress GC apoptosis, probably through promoting BMP-7 expression and following inhibiting caspase-3 activation.

The effects and mechanism of taxanes on chemotherapy-associated ovarian damage: A review of current evidence

Chemotherapy is often a cause of premature ovarian insufficiency and infertility since the ovarian follicles are extremely sensitive to the effects of chemotherapeutic agents. Different chemotherapeutic agents with varying mechanisms of action may damage ovarian function differently. Taxanes are widely used in clinical cancer treatment, but the specific reproductive toxicological information is still controversial. This review described the impact and duration of taxanes on ovarian function in women and analyzed the possible reasons for different conclusions. Furthermore, the toxicity of taxanes on ovarian function and its possible mechanisms were discussed. The potential protective strategies and agents against ovarian damage induced by taxanes are also reviewed.

A Warning Call for Fertility Preservation Methods for Women Undergoing Gonadotoxic Cancer Treatment

Malignant hematological conditions have recognized an increased incidence and require aggressive treatments. Targeted chemotherapy, accompanied or not by radiotherapy, raises the chance of defeating the disease, yet cancer protocols often associate long-term gonadal consequences, for instance, diminished or damaged ovarian reserve. The negative effect is directly proportional to the types, doses, time of administration of chemotherapy, and irradiation. Additionally, follicle damage depends on characteristics of the disease and patient, such as age, concomitant diseases, previous gynecological conditions, and ovarian reserve. Patients should be adequately informed when proceeding to gonadotoxic therapies; hence, fertility preservation should be eventually regarded as a first-intention procedure. This procedure is most beneficial when performed before the onset of cancer treatment, with the recommendation for embryos or oocytes’ cryopreservation. If not feasible or acceptable, several options can be available during or after the cancer treatment. Although not approved by medical practice, promising results after in vitro studies increase the chances of future patients to protect their fertility. This review aims to emphasize the mechanism of action and impact of chemotherapy, especially the one proven to be gonadotoxic, upon ovarian reserve and future fertility. Reduced fertility or infertility, as long-term consequences of chemotherapy and, particularly, following bone marrow transplantation, is often associated with a negative impact of recovery, social and personal life, as well as highly decreased quality of life.

Female Oncofertility: Current Understandings, Therapeutic Approaches, Controversies, and Future Perspectives

Recent advances in early detection and oncological therapies have ameliorated the survival rate of young cancer patients. Yet, ovarian impairment induced by chemotherapy and radiotherapy is still a challenging issue. This review, based on clinical and lab-based studies, summarizes the evidence of gonadotoxicity of chemoradiotherapy, the recent approaches, ongoing controversies, and future perspectives of fertility preservation (FP) in female patients who have experienced chemo- or radio-therapy. Existing data indicate that chemotherapeutic agents induce DNA alterations and massive follicle activation via the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway. Meanwhile, the radiation causes ionizing damage, leading to germ cell loss. In addition to the well-established methods, numerous therapeutic approaches have been suggested, including minimizing the follicle loss in cryopreserved ovarian grafts after transplantation, in vitro activation or in vitro growing of follicles, artificial ovarian development, or fertoprotective adjuvant to prevent ovarian damage from chemotherapy. Some reports have revealed positive outcomes from these therapies, whereas others have demonstrated conflictions. Future perspectives are improving the live birth rate of FP, especially in patients with adverse ovarian reserve, eliminating the risk of malignancy reintroducing, and increasing society’s awareness of FP importance.

Establishment and Mechanism Study of a Primary Ovarian Insufficiency Mouse Model Using Lipopolysaccharide

This study is aimed at establishing a lipopolysaccharide- (LPS-) induced primary ovarian insufficiency (POI) mouse model and investigating the underlying mechanism. C57BL/6N female mice were intraperitoneally injected with low-dose LPS (0.5 mg/kg) once daily for 14 days, high-dose LPS (2.5 mg/kg) twice weekly for 2 weeks, or cyclophosphamide (CTX; 150 mg/kg) once weekly for 2 weeks. Ovarian function was assessed by measuring the length of estrous cycle, the number of primordial follicles, and the levels of serum hormones. Expression and production of interleukin 1β (IL-1β) were determined to evaluate ovarian inflammation. Histopathological examination was performed to examine ovarian fibrosis. TUNEL assay was carried out to evaluate granulosa cell apoptosis. Western blotting was performed to measure the levels of inflammation-, fibrosis-, and apoptosis-related proteins in the mouse ovaries. Like CTX, both low- and high-dose LPS significantly impaired ovarian functions in mice, as evidenced by extended lengths of estrous cycles, reduced counts of primordial follicles, and alterations in the levels of serum hormones. Also, LPS promoted granulosa cell apoptosis and ovarian fibrosis in mice. However, LPS but not CTX promoted IL-1β expression and production in mice. Moreover, LPS but not CTX enhanced TLR, p-p65, p65, and MyD88 expression in mouse ovaries, suggesting that LPS differs from CTX in triggering ovarian inflammation. In general, continuous low-dose LPS stimulation was less potent than high-dose LPS to affect the ovarian functions. In conclusion, LPS may induce ovarian inflammation, fibrosis, and granulosa cell apoptosis and can be used to establish a POI model in mice.

Effects of PD-1 blockade on ovarian follicles in a prepubertal female mouse

Immunotherapy has emerged at the forefront of cancer treatment. Checkpoint inhibitor pembrolizumab (KEYTRUDA), a chimeric antibody which targets programmed cell death protein 1 (PD-1), has been approved by the Food and Drug Administration (FDA) for use in pediatric patients with relapsed or refractory classical Hodgkin's lymphoma. However, there is currently no published data regarding the effects of pembrolizumab on the ovary of female pediatric patients. In this study, prepubertal immunocompetent and immunodeficient female mice were injected with pembrolizumab or anti-mouse PD-1 antibody. The number of primordial follicles significantly decreased post-injection of both pembrolizumab and anti-mouse PD-1 antibody in immunocompetent mice. However, no changes in follicle numbers were observed in immunodeficient nude mice. Superovulation test and vaginal opening experiments suggest that there is no difference in the number of cumulus-oocyte complexes (COCs) and the timing of puberty onset between the control and anti-mouse PD-1 antibody treatment groups, indicating that there is no effect on short-term fertility. Elevation of pro-inflammatory cytokine TNF-α following COX-2 upregulation was observed in the ovary. CD3+ T-cell infiltration was detected within some ovarian follicles and between stromal cells of the ovaries in mice following treatment with anti-mouse PD-1 antibody. Thus, PD-1 immune checkpoint blockade affects the ovarian reserve through a mechanism possibly involving inflammation following CD3+ T-cell infiltration.

Ovarian tissue and oocyte cryopreservation prior to iatrogenic premature ovarian insufficiency

Gonadotoxic treatments like chemotherapy or radiotherapy and ovarian surgery may result in an accelerated depletion of the ovarian reserve and subsequent premature ovarian insufficiency. Important determinants of this severe risk that require fertility preservation strategies are patient age, ovarian reserve, type of treatment, and administered dose. Oocytes and ovarian tissue can both be cryopreserved, with encouraging results in terms of pregnancy and live birth rates according to recent publications. Moreover, since ovarian tissue transplantation also results in long-term endocrine resumption, it represents a potential future therapeutic option for complete ovarian function restoration in patients with premature ovarian insufficiency.