Effects of cyclophosphamide administration on the in vitro fertilization of mice

Targeting Estrogen Receptor Beta Ameliorates Diminished Ovarian Reserve via Suppression of the FOXO3a/Autophagy Pathway

Diminished ovarian reserve (DOR) refers to a decrease in the number and/or quality of oocytes, leading to infertility, poor ovarian response and adverse pregnancy outcomes. Currently, the pathogenesis of DOR is largely unknown, and the efficacy of existing therapeutic methods is limited. Therefore, in-depth exploration of the mechanism underlying DOR is highly important for identifying molecular therapeutic targets for DOR. Our study showed that estrogen receptor beta (ERβ) mRNA and protein expression was upregulated in granulosa cells (GCs) from patients with DOR and in the ovaries of DOR model mice. Mechanistically, elevated ERβ promotes forkhead transcription factor family 3a (FOXO3a) expression, which contributes to autophagic activation in GCs. Activation of FOXO3a/autophagy signalling leads to decreased cell proliferation and increased cell apoptosis and ultimately leads to DOR. In a cyclophosphamide (Cy)-induced DOR mouse model, treatment with PHTPP, a selective ERβ antagonist, rescued fertility by restoring normal sex hormone secretion, estrus cycle duration, follicle development, oocyte quality and litter size. Taken together, these findings reveal a pathological mechanism of DOR based on ERβ overexpression and identify PHTPP as a potential therapeutic agent for DOR.

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.

Extended adverse effects of cyclophosphamide on mouse ovarian function

PURPOSE

Most patients with cancer undergo multiple administrations of anticancer drugs during treatment, resulting in chronic impairment of their reproductive health. As improved treatment options increase cancer survival, it has become increasingly important to address fertility issues in cancer survivors. In this study, we examined the pathophysiological effects of multiple exposures to cyclophosphamide (Cy) on the ovaries of mice and their underlying molecular mechanism.

METHODS

Female C57BL/6 mice were intraperitoneally injected with 100 mg/kg Cy six times over 2 weeks; 4 weeks later, the mice were sacrificed and their ovaries, sera, and oocytes were collected for histological observation, measurement of anti-Müllerian hormone levels, and assessment of oocyte quantity and quality in response to hormonal stimulation. Gene expression changes in Cy-treated ovaries were examined by microarray and bioinformatics analyses.

RESULTS

After repeated Cy exposure, the anti-Müllerian hormone level was decreased, and follicle loss and impairments in the quality of oocyte were irreversible. The expression levels of genes involved in folliculogenesis, oogenesis, and zona pellucida glycoprotein transcription displayed sustained alterations in Cy-exposed ovaries even after 4 weeks.

CONCLUSION

The adverse effects of Cy on ovarian function and oocytes remained even after chemotherapy was complete. Therefore, strategies to prevent ovarian damage or restore ovarian function after treatment are required to safeguard the fertility of young cancer survivors.

Upregulation of FSHR and PCNA by administration of coenzyme Q10 on cyclophosphamide-induced premature ovarian failure in a mouse model

Cyclophosphamide (CTX) has been broadly used in the clinic for the treatment of autoimmune disorders and ovarian cancer. The process of chemotherapy has significant toxicity in the reproductive system as it has detrimental effects on folliculogenesis, which leads to an irreversible premature ovarian failure (POF). Coenzyme Q10 (CoQ10) has positive impacts on the reproductive system due to its antioxidant properties, protecting the cells from free-radical oxidative damage and apoptosis. However, little is known about the possible synergistic effect of CTX and CoQ10 on the expression of genes involved in folliculogenesis, such as proliferation cell nuclear antigen (PCNA) and follicle-stimulating hormone receptor (FSHR). A total of 32 NMRI mice were applied and divided into four groups, including healthy control, CTX, CTX + CoQ10, and CoQ10 groups. The effects of CoQ10 on CTX-induced ovarian injury and folliculogenesis were examined by histopathological and real-time quantitative reverse transcription-polymerase chain reaction analyses. The rates of fertilization (in vitro fertilization), embryo development, as well as the level of reactive oxygen species (ROS) in metaphase II (MII) mouse oocytes after PMSG/HCC treatment were also assessed. Results showed that the treatment with CTX decreased the mRNA expression of PCNA and FSHR, IVF rate, and embryo development whereas the application of CoQ10 successfully reversed those factors. CoQ10 administration significantly enhanced histological morphology and decreased ROS levels and the number of atretic follicles in the ovary of CTX-treated mice. In conclusion, it seems that the protective effect of CoQ10 is exerted via the antioxidant and proliferative properties of this substance on CTX-induced ovarian damage.

Association between spontaneous ovulation and serum anti-Müllerian hormone levels in a premature ovarian insufficiency patient after a multimodal treatment for breast cancer

The high toxicity of chemotherapy can damage a patient's gonadal function, leading to premature ovarian insufficiency (POI). Here, we report the case of a patient suffering from POI after chemotherapy for breast cancer, who 3 years later ovulated spontaneously and became pregnant. The patient, a 31-year-old infertile women, nulligravida, was diagnosed with breast cancer. The Anti-Müllerian Hormone (AMH) level in her serum was 1.85 ng/mL before multimodal treatment for cancer. She later visited our hospital for amenorrhea and 2 years after cancer treatment, she was diagnosed with POI. Her AMH level at that point was less than 0.1 ng/mL. One year after the diagnosis of POI, the patient's AMH level increased slightly to 0.14 ng/mL and she ovulated spontaneously. The patient later became pregnant using Assisted Reproductive Technology on the fourth attempt.During the course of treatment for infertility at our hospital, the AMH levels in her serum changed along with the recovery of ovarian function. These findings suggest the possibility that ovulation and pregnancy could be predicted by the chronological changes of the AMH levels in the patient's serum.