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

Shanyao regulates the PI3K/AKT/P21 pathway to promote oogonial stem cell proliferation and stemness restoration to alleviate premature ovarian insufficiency

ETHNOPHARMACOLOGICAL RELEVANCE

Shanyao (SY, yam, Rhizoma Dioscoreae, the dried rhizome of Dioscorea oppositifolia L.) was recorded in the Chinese pharmacopoeia and was often used in the treatment of premature ovarian insufficiency (POI).

AIM OF STUDY

To evaluate the efficacy of shanyao in cyclophosphamide (CTX)-induced POI and explore its potential mechanism of action.

MATERIAL AND METHODS

We employed network pharmacology, Liquid Chromatograph Mass Spectrometer (LC-MS), and molecular docking methods to identify active compounds and core targets, and predict the mechanism of shanyao for treating POI. The mechanism was subsequently validated through a series of experiments. Female Sprague-Dawley (SD) rats were randomly divided into five groups: control (CON), model, estradiol valerate (EV), low-dose shanyao, and high-dose shanyao. An experimental rat model of POI was established using cyclophosphamide and treated with either shanyao or EV for a duration of two months. We assessed the efficacy of shanyao in vivo through methods such as weighing, Enzyme-linked Immunosorbent Assay (ELISA), and Hematoxylin and Eosin (H&E) staining. Oogonial stem cells (OSCs) were isolated, after modeling, treated them with a serum containing either shanyao or EV. Using methods such as CCK8 assay, immunofluorescence staining, flow cytometry (FCM) analysis, and Western blot analysis to verify the mechanism of shanyao in treating POI.

RESULTS

In this study, we found that after treatment with shanyao, the general condition of POI rats was improved, body weight and the ratio of ovarian weight to body weight were increased, FSH, E2 and AMH levels were improved, primary follicles and preantral follicles were significantly increased, atretic follicles were decreased. However, the number of antral follicles and fresh corpus luteum was no statistical difference. We identified 10 active compounds of shanyao that act on 220 target genes, 176 of which are associated with POI. Denudatin B and Kadsurenone were finally identified as core components. Through topological analysis, 18 key targets were selected, and ultimately PI3K, CCND1, and CDK4 were identified as core targets. Molecular docking results showed that core components had good binding energy with core targets. The results of GO and KEGG enrichment analysis mainly focus on cell cycle regulation and PI3K/AKT signaling pathway. A series of molecular biology experiments confirmed that after shanyao treatment, the phosphorylation level of PI3K and AKT in POI rats were increased, P21 was inhibited, PI3K/AKT/P21 signaling pathway was activated, and the expression levels of CCND1 and CDK4 were increased. At the same time, the expression of Oct4, fragilis and Mvh of ovarian stem cells was up-regulated.

CONCLUSION

The active compounds of shanyao can regulate the PI3K/AKT/P21 signaling pathway, promote the proliferation of oogonial stem cells, stemness restoration, and delay ovarian aging. This study provides valuable insights into shanyao treatment for POI.

Autophagy and Female Fertility: Mechanisms, Clinical Implications, and Emerging Therapies

Autophagy, an evolutionarily conserved cellular mechanism essential for maintaining internal stability, plays a crucial function in female reproductive ability. In this review, we discuss the complex interplay between autophagy and several facets of female reproductive health, encompassing pregnancy, ovarian functions, gynecologic malignancies, endometriosis, and infertility. Existing research emphasizes the crucial significance of autophagy in embryo implantation, specifically in the endometrium, highlighting its necessity in ensuring proper fetal development. Although some knowledge has been gained, there is still a lack of research on the specific molecular impacts of autophagy on the quality of oocytes, the growth of follicles, and general reproductive health. Autophagy plays a role in the maturation, quality, and development of oocytes. It is also involved in reproductive aging, contributing to reductions in reproductive function that occur with age. This review explores the physiological functions of autophagy in the female reproductive system, its participation in reproductive toxicity, and its important connections with the endometrium and embryo. In addition, this study investigates the possibility of emerging treatment approaches that aim to modify autophagy, using both natural substances and synthetic molecules, to improve female fertility and reproductive outcomes. Additionally, this review intends to inspire future exploration into the intricate role of autophagy in female reproductive health by reviewing recent studies and pinpointing areas where current knowledge is lacking. Subsequent investigations should prioritize the conversion of these discoveries into practical uses in the medical field, which could potentially result in groundbreaking therapies for infertility and other difficulties related to reproduction. Therefore, gaining a comprehensive understanding of the many effects of autophagy on female fertility would not only further the field of reproductive biology but also open new possibilities for diagnostic and treatment methods.

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.

Ovarian Insufficiency and Fertility Preservation During and After Childhood Cancer Treatment

Premature ovarian insufficiency (POI) is one of many potential long-term consequences of childhood cancer treatment in females. Causes of POI in this patient population can include chemotherapy, especially alkylating agents, and radiation therapy. Rarely, ovarian tumors lead to ovarian dysfunction. POI can manifest as delayed pubertal development, irregular menses or amenorrhea, and infertility. This diagnosis often negatively impacts emotional health due to the implications of impaired ovarian function after already enduring treatment for a primary malignancy. The emerging adult may be challenged by the impact on energy level, quality of life, and fertility potential. POI can also lead to low bone density and compromised skeletal strength. This review discusses the health consequences of POI in childhood cancer survivors (CCS). We also explore the role of fertility preservation for CCS, including ovarian tissue cryopreservation and other available options. Lastly, knowledge gaps are identified that will drive a future research agenda.

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.

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.