Assessment of fertility protection and ovarian reserve with GnRH antagonist in rats undergoing chemotherapy with cyclophosphamide

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 and fertility. Chemotherapy-induced ovarian damage has been concerned, apart from ovarian preservation, the prevention and treatment of ovarian dysfunction are widely studied. In this article, the mechanisms of ovarian injury caused by chemotherapy, including the apoptosis of follicle and supporting cells, follicle "burn out", ovarian stromal and microvascular damage; and influencing factors, including age at diagnosis and 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 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 ovary, etc.

Effects of Cetrorelix on Ovary and Endometrium Prior to Anti-PD-L1 Antibody in Murine Model

BACKGROUND

Recent anti-cancer agents, immune checkpoint inhibitors (ICIs), have emerged as effective agents targeting the programmed cell death protein-1 (PD-1)/programmed death-ligand 1 (PD-L1) pathway. While the administration of gonadotropin-releasing hormone (GnRH) analogs before cytotoxic agents is known to preserve female reproductive organ function, the potential effects of ICIs and the protective impact of GnRH analogs on female reproductive organs, especially concerning ovarian reserve and endometrial receptivity, remain unknown. In this study, we attempted to elucidate the protective or regenerative effect on the female reproductive organ of cetrorelix prior to anti-PD-L1 antibody administration.

METHOD

Using a murine model, we examined the effects of Anti-PD-L1 antibody treatment on ovarian and uterine morphology, compared them with controls, and further assessed any potential protective effect of cetrorelix, a GnRH analog. Histological examinations and quantitative reverse transcription polymerase chain reaction were employed to study the morphological changes and associated gene expression patterns.

RESULTS

Anti-PD-L1 treatment led to a significant depletion of primordial/primary ovarian follicles and impaired decidualization in uterine stromal cells. However, while pretreatment with cetrorelix could restore normal decidualization patterns in the uterus, it did not significantly ameliorate ovarian follicular reductions. Gene expression analysis reflected these observations, particularly with marked changes in the expression of key genes like Prl and Igfbp1, pivotal in uterine decidualization.

CONCLUSION

Our study underscores the potential reproductive implications of cetrorelix treatment prior to Anti-PD-L1 therapy, shedding light on its short-term protective effects on the uterus. Further studies are necessary to understand long-term and clinical implications.

GnRH Analogues as a Co-Treatment to Therapy in Women of Reproductive Age with Cancer and Fertility Preservation

In this review, we analyzed existing literature regarding the use of Gonadotropin-releasing Hormone (GnRH) analogues (agonists, antagonists) as a co-treatment to chemotherapy and radiotherapy. There is a growing interest in their application as a prophylaxis to gonadotoxicity caused by chemotherapy and/or radiotherapy due to their ovarian suppressive effects, making them a potential option to treat infertility caused by such chemotherapy and/or radiotherapy. They could be used in conjunction with other fertility preservation options to synergistically maximize their effects. GnRH analogues may be a valuable prophylactic agent against chemotherapeutic infertility by inhibiting rapid cellular turnover on growing follicles that contain types of cells unintentionally targeted during anti-cancer treatments. These could create a prepubertal-like effect in adult women, limiting the gonadotoxicity to the lower levels that young girls have. The use of GnRH agonists was found to be effective in hematological and breast cancer treatment whereas for ovarian endometrial and cervical cancers the evidence is still limited. Studies on GnRH antagonists, as well as the combination of both agonists and antagonists, were limited. GnRH antagonists have a similar protective effect to that of agonists as they preserve or at least alleviate the follicle degradation during chemo-radiation treatment. Their use may be preferred in cases where treatment is imminent (as their effects are almost immediate) and whenever the GnRH agonist-induced flare-up effect may be contra-indicated. The combination treatment of agonists and antagonists has primarily been studied in animal models so far, especially rats. Factors that may play a role in determining their efficacy as a chemoprotective agent that limits gonadal damage, include the type and stage of cancer, the use of alkylating agents, age of patient and prior ovarian reserve. The data for the use of GnRH antagonist alone or in combination with GnRH agonist is still very limited. Moreover, studies evaluating the impact of this treatment on the ovarian reserve as measured by Anti-Müllerian Hormone (AMH) levels are still sparse. Further studies with strict criteria regarding ovarian reserve and fertility outcomes are needed to confirm or reject their role as a gonadal protecting agent during chemo-radiation treatments.

An assessment of the protective effect of gonadotropin-releasing hormone agonist and antagonist on bleomycin-induced ovarian toxicity in rats

The aim of this study is to evaluate the effect of GnRH agonist or GnRH antagonist therapy on bleomycin-administered rats by examining ovarian follicle counts and AMH levels. A total of 30 female Wistar albino rats aged 4-6 months were randomly divided into 4 groups. First, an intramuscular injection of bleomycin (30 mg/m2) was administered to all except the control group on the 1st, 8th and 15th days. The control group (Group I) was administered 0.1 mL intramuscular saline on those days. The bleomycin group (Group II) was followed up without any further treatment. The bleomycin + GnRH agonist group (Group III) was administered subcutaneous GnRH agonist triptorelin (1 mg/kg) at the same time as the bleomycin injections. The bleomycin + GnRH antagonist group (Group IV) was administered 1 mg/kg cetrorelix acetate subcutaneously, concurrently with the bleomycin. Although AMH levels were lower in the bleomycin group than in all the other groups, there was no statistically significant difference between the groups in terms of AMH levels (p > .05). In the bleomycin + cetrorelix acetate and bleomycin + triptorelin groups, significantly higher primordial, secondary and tertiary follicle counts were determined compared to the bleomycin group (p < .001). In conclusion the harmful effects of bleomycin on ovarian reserve can be reduced by the simultaneous administration of GnRH agonist or GnRH antagonist.

Protective effect of alpha-lipoic acid and omega-3 fatty acids against cyclophosphamide-induced ovarian toxicity in rats

Background and Aim:

Cyclophosphamide therapy is known to be associated with the risk of female infertility as a result of ovarian toxicity. Alpha-lipoic acid (LA) and omega-3 fatty acids are known for their antioxidant and anti-inflammatory activities. The present study investigated the potential protective effect of alpha-LA, omega-3 fatty acids, and its combination against cyclophosphamide-induced ovarian toxicity in rats.

Materials and Methods:

Thirty rats were equally divided into Groups I, II, III, IV, and V. Group I was normal control, wherein the rats were fed with normal feed and water ad libitum. Group II served as cyclophosphamide-induced group, wherein the rats were injected with cyclophosphamide at 75 mg/kg through intraperitoneal route once a week to induce ovarian toxicity. Groups III and IV were treated with alpha-LA at the rate of 25 mg/kg and omega-3 fatty acids at the rate of 400 mg/kg, respectively, in parallel to cyclophosphamide induction as in Group II. Group V animals were coadministered with alpha-LA (25 mg/kg) and omega-3 fatty acids (400 mg/kg) along with cyclophosphamide induction as in Group II. The respective treatments were administered daily through oral route for a period of 30 days. Regularity of estrous cycle was evaluated by vaginal cytology. Post-treatment period, the animals were humanely sacrificed, and the blood samples were subjected to the estimation of follicle-stimulating hormone (FSH) and estrogen. The ovarian tissue was weighed and subjected to histopathology, transmission electron microscopy, estimation of decreased glutathione (GSH), and tumor necrosis factor (TNF)-alpha.

Results:

Rats treated with cyclophosphamide alone manifested irregularity in estrous cycle, increased FSH, and reduced estrogen levels. The ovaries showed decreased GSH and increased TNF-alpha concentrations. Histopathological and transmission electron microscopic analysis of the ovarian follicles revealed degenerative changes. Administration of alpha-LA and omega-3 fatty acids as well as the combination of both the treatments demonstrated significant normalization of the estrous cycle and antioxidant defense mechanism as well as ameliorated the hormonal profile and histological architecture of the ovarian follicles. However, appreciable synergistic efficacy of the combination therapy (alpha-LA+omega-3 fatty acids) with respect to the monotherapies was not observed in the present study.

Conclusion:

The efficacy of alpha-LA and omega-3 fatty acids against cyclophosphamide-induced ovarian toxicity could be attributed to its antioxidant and anti-inflammatory activities that prevented the oxidative damage to the ovaries caused by cyclophosphamide. Hence, our findings suggest that dietary supplementation of alpha-LA and omega-3 fatty acids in women receiving cyclophosphamide therapy could carry potential benefits in preventing cyclophosphamide-induced infertility in childbearing women.

Both in vivo FSH depletion and follicular exposure to Gonadotrophin-releasing hormone analogues in vitro are not effective to prevent follicular depletion during chemotherapy in mice

STUDY QUESTION

Does fertility preservation using gonadotrophin-releasing hormone (GnRH) analogues during chemotherapy act through a direct effect on the ovary or through inhibition of FSH secretion?

SUMMARY ANSWER

The absence of FSH in vivo and the direct exposition of ovarian follicles to GnRH analogues in vitro did not prevent chemotherapy-induced ovarian damage.

WHAT IS KNOWN ALREADY

The potential mechanisms of action of GnRH analogues in protecting ovaries against chemotherapy damage remain poorly understood. We previously showed that GnRH analogues have a limited inhibitory effect on gonadotropin secretion and follicular growth in mice.

STUDY DESIGN SIZE, DURATION

Mouse models were developed to independently evaluate (i) the indirect effect of FSH depletion on chemotherapy-induced ovarian damage using Fshb-deficient (-/-) mice to mimic the profound inhibition of FSH secretion during GnRH analogues treatment and (ii) the direct in vitro effect of GnRH agonist and antagonist in follicles exposed to chemotherapy using a follicular culture system.

PARTICIPANTS/MATERIALS, SETTING, METHODS

To assess the indirect effect of GnRH analogues through FSH inhibition, Fshb-/- mice were treated with 1 IU pregnant mare serum gonadotropin (control group) or saline (study group) for 7 days and with cyclophosphamide (200 mg/kg) on Day 5. Ovaries were collected 48 h post-cyclophosphamide to evaluate ovarian reserve, cellular apoptosis and proliferation. To evaluate the direct effects of GnRH analogues on growing follicles, isolated preantral follicles from prepubertal mice were cultured in vitro for 13 days with 1 μM GnRH analogues and 20 μM of 4-hydroperoxycyclophosphamide or not at Day 4. Oocytes were matured by adding epidermal growth factor (EGF)/hCG on Day 12. Follicular development, follicular survival, oocyte maturation rates, cAMP production, and steroidogenesis were evaluated. To assess the direct GnRH analogues effects on follicular reserve, whole neonatal ovaries were cultured in vitro under the same conditions for 2 days. Ovaries were processed 24 h post-chemotherapy for ovarian reserve, cellular apoptosis and proliferation analysis.

MAIN RESULTS AND THE ROLE OF CHANCE

Cyclophosphamide induced a significant follicular loss of more than 50% in Fshb-/- mice regardless of previous treatment with gonadotropins and no difference was observed in cell proliferation or apoptosis. In vitro experiments on growing follicles showed that 4-hydroperoxycyclophosphamide significantly decreased preantral follicle survival and maturation rates (55% and 37%, respectively) and delayed follicular development, regardless of the presence of GnRH analogues. Chemotherapy reduced granulosa cell numbers in all groups, while no change in cAMP production/106 granulosa cells was observed. Similarly, 4-hydroperoxycyclophosphamide induced apoptosis and significant follicular loss in cultured neonatal ovaries irrespective of GnRH analogues exposure.

LIMITATIONS REASONS FOR CAUTION

As ovarian GnRH receptors expression differs in humans and mice, further studies are needed to validate our results in human ovaries.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings demonstrate that ovarian damage occurred even in the absence of FSH, suggesting that inhibition of the pituitary-gonadal axis is not involved in ovarian protection during GnRH analogues treatment. Using in vitro models, no evidence for direct protective effect of GnRH analogues against cyclophosphamide metabolite damage was observed. At present, clinical efficiency of GnRH analogues to prevent chemotherapy-induced ovarian damage remains highly debated and these experimental results reinforced the question as they did not bring evidence of direct or indirect mechanisms of protection.

LARGE SCALE DATA

N/A.

STUDY FUNDING AND COMPETING INTEREST(S)

This work was supported by the Belgian FNRS, 'Le Fonds Emile DEFAY', and 'La Fondation Rose et Jean Hoguet'. Authors have no conflict of interest to declare.

Could erythropoietin reduce the ovarian damage of cisplatin in female rats?

The aim of this study is to investigate whether erythropoietin (EPO) can reduce the ovarian damage of cisplatin or not. Thirty, female, Wistar-Albino rats were used in the study. Control group (N = 10): Intraperitoneal saline infusion, Cisplatin group (N = 10): Intraperitoneal 7 mg/kg cisplatin, Cisplatin + EPO group (N = 10): Intraperitoneal 7 mg/kg cisplatin and subcutaneous 200 IU/kg/day EPO. Serum AMH concentrations were measured by enzyme-linked immunosorbent assay kit of AMH. Follicular counts were evaluated according to mean diameter of the follicles. Ovarian damage; including follicular cell degeneration, vascular congestion, hemorrhage, and inflammation was scored histologically using a graduated scale. Posttreatment AMH levels of cisplatin group were significantly lower than control and cisplatin + EPO groups. In cisplatin group, there was a significant decrement in posttreatment AMH level compared to pretreatment AMH level. The total damage score of cisplatin group was significantly higher than scores of control and cisplatin + EPO groups. The mean primordial follicle counts of control and cisplatin + EPO groups were significantly higher than that of cisplatin group (p = .007 and p = .003). The results of this study revealed that EPO administration to cisplatin chemotherapy could ameliorate the ovarian damage. Erythropoietin administration to chemotherapeutic agents might suggest to protect ovarian failure and infertility.

A Combination of a GnRH Antagonist and Agonist for Fertility Preservation in an Adolescent Female Murine Model

Recent studies have suggested that GnRH agonists (GnRHags) protect ovarian function following chemotherapy. Here, we study the effect of a combination of GnRH antagonist (GnRHan) and GnRHag for gonadal protection from gonadotoxic chemotherapy in adolescent female rats. Cycling Sprague Dawley rats were treated at adolescent age. Thirty female rats were randomized to 5 treatment groups (n = 6/group): (1) placebo, (2) cyclophosphamide (CPA) alone, (3) GnRHan followed by GnRHag with placebo, (4) GnRHan followed by GnRHag with CPA, and (5) GnRHag with CPA. The main outcome measure was live birth rate (LBR), and secondary measures included rat weight, ovarian volume, and follicles. Group 2 had decreased LBR compared to all other groups. Group 4 and 5 had LBR similar to placebo. There was no difference in the ovarian volume. The CPA-alone group had decreased number of antral follicles compared to control. These studies demonstrate that the combination of GnRHan and GnRHag and GnRHag alone preserved fertility in female adolescent rats following gonadotoxic chemotherapy treatment. The addition of a GnRHan to a GnRHag does not confer a greater protective effect.

Triptorelin and cetrorelix induce immune responses and affect uterine development and expressions of genes and proteins of ESR1, LHR, and FSHR of mice

CONTEXT

GnRH immunity can reduce the expression of pituitary GnRH levels, and cause the changes in reproductive behaviors. It is unclear whether triptorelin (TRI) and cetrorelix (CET) immunity influences uterine development and expression of follicle-stimulating hormone receptor (FSHR), luteinizing hormone receptor (LHR), and estradiol receptor 1 (ERS1) in the uterus.

OBJECTIVE

The study investigated the effects of active immunity of GnRH agonist and antagonist on uterine development, microstructures, expression of hormone receptors mRNAs, and proteins in uteri.

MATERIALS AND METHODS

One hundred and five mice were assigned into CET, TRI, and control groups (CG). Mice in CET-1, CET-2, and CET-3 (n = 15) were subcutaneously injected with 10, 20, and 40 μg CET antigens for seven days, respectively. Mice in TRI-1, TRI-2, and TRI-3 were injected with 10, 20, and 40 μg TRI antigens for seven days, respectively. The qPCR and Western blot were implemented to determine expressions of ESR1, LHR and FSHR mRNAs, and proteins.

RESULTS

Compared with CG, the uterine weights of CET-1, CET-2, and CET-3 increased by 42.86, 62.86, and 10.00% on day 35 (p < 0.05), respectively. Uterine weights of TRI-2, TRI-3 reduced by 28.57% and 11.43% (p < 0.05), respectively. The uterine cavity in CET-1, CET-2, and CET-3 increased; the uterine wall became thick. The cytoplasm of endometrial epithelial cells (EEC) increased slightly. In TRI group, the uterine wall thinned. Uterine cavity became narrow slightly in TRI-1. Numbers of uterine glands reduced. The endometrium epithelial thickness (EET) in CET-1 and CET-2 increased by 68.21% and 79.46% (p < 0.05), respectively. EET in TRI-1 was decreased by 13.69%. Uterine wall thicknesses (UWT) in CET-1 and CET-2 were higher than CG, with the increment of 28.59% and 30.72%. UWT of TRI-1, TRI-2, and TRI-3 reduced by 29.35, 15.36, and 14.41%, respectively. Expressions of ESR1, FSHR, and LHR mRNAs in CET and TRI mice increased. ESR1 and FSHR protein levels increased in all experimental mice (p < 0.05), with a maximum of TRI-3. LHR protein levels of the CET decreased. LHR protein levels of TRI group increased, with a maximum of TRI-3 (p < 0.05). ESR1 protein level had significant negative correlations to mRNA expressions of ESR1, LHR, and FSHR.

CONCLUSIONS

CET immunity promoted the uterine development, improved EET and UWT, and also promoted the expressions of ESR1 and FSHR protein levels. It lessened the LHR protein levels. TRI immunity blocked EET and UWT, inhibited uterine growth and development. The efficacy of CET immunity was more obvious than TRI.

Folliculogenesis Is Not Fully Inhibited during GnRH Analogues Treatment in Mice Challenging Their Efficiency to Preserve the Ovarian Reserve during Chemotherapy in This Model

As many chemotherapy regimens induce follicular depletion, fertility preservation became a major concern in young cancer patients. By maintaining follicles at the resting stage, gonadotropin-releasing hormone analogues (GnRHa) were proposed as an ovarian-protective option during chemotherapy. However, their efficacy and mechanisms of action remain to be elucidated. Mice were dosed with cyclophosphamide (Cy, 100–500mg/kg i.p) to quantify follicular depletion and evaluate apoptosis at different times. We observed a dose-dependent depletion of the follicular reserve within 24 hours after Cy injection with a mean follicular loss of 45% at the dose of 200mg/kg. Apoptosis occurs in the granulosa cells of growing follicles within 12 hours after Cy treatment, while no apoptosis was detected in resting follicles suggesting that chemotherapy acutely affects both resting and growing follicles through different mechanisms. We further tested the ability of both GnRH agonist and antagonist to inhibit oestrus cycles, follicular growth and FSH secretion in mice and to protect ovarian reserve against chemotherapy. Although GnRHa were efficient to disrupt oestrus cycles, they failed to inhibit follicular development, irrespective of the doses and injection sites (sc or im). Around 20% of healthy growing follicles were still observed during GnRHa treatment and serum FSH levels were not reduced either by antagonist or agonist. GnRHa had no effect on Cy-induced follicular damages. Thus, we showed that GnRHa were not as efficient at inhibiting the pituitary-gonadal axis in mice as in human. Furthermore, the acute depletion of primordial follicles observed after chemotherapy does not support the hypothesis that the ovary may be protected by gonadotropin suppression.

Protective effects of sildenafil citrate administration on cisplatin-induced ovarian damage in rats

The aim of this study is to evaluate the effects of sildenafil citrate on cisplatin-induced ovarian toxicity. Thirty-two female rats were divided into four groups. Group 1: saline control; group 2: cisplatin; group 3: sildenafil citrate; and group 4: cisplatin plus sildenafil citrate group. In groups 2 and 4, the rats were injected with 5 mg/kg cisplatin intraperitoneally (i.p.). In groups 3 and 4, the rats were injected with 1.4 mg/kg sildenafil citrate i.p. The ovaries were removed two weeks later in all groups. Histopathologic examination, follicle counting and classification were performed. The expression of anti-Müllerian hormone (AMH) was detected immunohistochemically in the ovarian tissues. Sildenafil alleviated cisplatin-induced histopathological changes in the ovarian tissue. Primordial, secondary and tertiary follicles were diminished in group 2 compared with group 1 (p < 0.05). Pretreatment with sildenafil citrate preserved primordial follicle count in group 4 compared with group 2, and the difference was statistically significant (p < 0.05). According to our results, immunoreactivity intensity of AMH was lower in group 2 compared with group 1 (92.4 ± 3.97 versus 88.8 ± 1.77) but not significantly, whereas immunoreactivity intensity of AMH was higher in group 4 compared with group 2 (88.8 ± 1.77 versus 94.1 ± 2.36; p < 0.05). Our results demonstrated that pretreatment with sildenafil citrate is beneficial for protecting the ovaries from cisplatin-induced damage. Sildenafil citrate can be a choice for fertility preservation.

Protective effect of mirtazapine and hesperidin on cyclophosphamide-induced oxidative damage and infertility in rat ovaries

Cyclophosphamide (CP) causes infertility due to ovarian toxicity. The toxicity mechanism suggests oxidative stress. We assessed whether mirtazapine (MTZ) and hesperidin (HSP) could promote ovarian protection against damage due to CP chemotherapy. Female Wistar rats aged 14 weeks were used. Animals were divided into four groups: control vehicle group (n = 8); CP group (n = 8, rats received 150 mg/kg of CP, single intraperitoneal [i.p.] injection); CP + MTZ group (n = 8, rats received same dose of CP + 30 mg/kg of MTZ, orally, daily); and HSP + CP group (n = 8, rats received same dose of CP + 100 mg/kg of HSP, orally, daily). After eight days of medication, ovaries were removed and ovarian toxicity was assessed by counting follicles and corpora lutea. Nitric oxide (NO) and malondialdehyde (MDA) levels, myeloperoxidase (MPO), glutathione peroxidase (GPx), and superoxide dismutase (SOD) activities were estimated in ovarian tissue. NO level, MDA level, and MPO activity were increased (P < 0.001), while, GPx and SOD activities were lowered significantly (P < 0.001) in CP-treated group compared with control vehicle. In addition, ovulation, number of follicles, and ovarian weight were reduced by CP treatment. On the contrary, rats pretreated with MTZ and HSP showed significant decrease in NO, MDA levels, and MPO activity, while, activities of SOD and GPx were increased (P < 0.001). Oxidative stress induced by CP in the rat ovary causes infertility in the female rats. HSP and MTZ could reverse this effect and provide protection of fertility against CP-induced toxicity.

Protective effect of dienogest on chemotherapy-induced reduced fertility in female rats

Reduced fertility is one of the main long-term consequences of chemotherapy given for lymphoma, leukemia, and other malignancies in young women. We examined with a female rat model whether and how dienogest, a fourth-generation progestin, modulates reduced fertility following exposure to gonadotoxic chemotherapy. Female rats were administered cyclophosphamide with or without GnRH agonist and different concentrations of dienogest for 20 days. Animals were sacrificed on Day 29, and the numbers of follicle at primordial, preantral and antral stage in the ovaries were counted histologically. Rats treated with sterile saline solution (as control), cyclophosphamide, cyclophosphamide plus GnRH agonist, and cyclophosphamide plus dienogest were also mated with male rats to evaluate their fertility and pregnancy outcomes. Cyclophosphamide significantly reduced the number of primordial follicles, whereas dienogest suppressed depletion of primordial follicle pool induced by chemotherapy. Although the rats exposed to cyclophosphamide alone failed to deliver live births, co-treatment with dienogest improved the pregnancy outcomes of treated rats. The protective effect of dienogest on chemotherapy-induced ovarian damage and reduced fertility was comparable to that of GnRH agonist. The present results suggest that the co-administration of dienogest and chemotherapy may be a useful strategy in preserving ovarian function and fertility in premenopausal women facing gonadotoxic chemotherapy.

Combination of a GnRH agonist with an antagonist prevents flare-up effects and protects primordial ovarian follicles in the rat ovary from cisplatin-induced toxicity: a controlled experimental animal study

BACKGROUND

With the continuous improvement of surgery and chemotherapeutic treatments, many tumour patients increasingly achieve long-term survival and can even be completely cured. However, platinum-containing drugs, which are widely used to treat a variety of types of cancer, cause menstrual disorders and ovarian failure, which in turn lead to infertility. Thus far, gonadotropin releasing hormone (GnRH) agonist (GnRHa) and antagonist (GnRHant) are reported to act as protective agents of the ovary in chemotherapy through the inhibition of the female gonadal axis. Nevertheless, they both have disadvantages that limit their use. GnRHa causes a flare-up effect during the first week after administration, and no long-acting GnRHant agent is available. GnRHa combined with GnRHant may prevent the flare-up effect of GnRHa and rapidly inhibit the female gonadal axis. Several clinical studies with small sample sizes have reported controversial conclusions. In this strictly controlled animal study, we investigated the advantages of combination treatment with GnRHa and GnRHant.

METHODS

Rats aged 12 weeks were divided into six groups: Control, cisplatin (CDDP), GnRHa, GnRHant, Combination (sht, short-term) and Combination (lng, long-term) of GnRHa and GnRHant. The last four groups received Triptorelin (1 mg/kg·d, for 14 days), Cetrorelix (0.5 mg/kg·d, for 10 days), a combination of Triptorelin (1 mg/kg·d, for 10 days) and Cetrorelix (0.5 mg/kg·d, for 10 days) in the long-term group and for 3 days in the short-term group. The Control and CDDP groups received saline (1 ml/kg·d, for 10 day). Then, all groups apart from the Control group received cisplatin (1 mg/kg·d, for 10 days), and the Control group received another 10 days of saline as described above. Blood samples were collected to detect the serum levels of E2, LH and FSH. Observation of oestrous cyclicity was also performed after drug administration. Finally, bilateral ovaries were collected for histological study and follicle counting.

RESULTS

We observed a flare-up effect in rats treated with GnRHa, but not in any of the combination groups. The percentage of normal cyclicity increased from 0% in the CDDP group to 25.0%, 33.3%, 66.7% and 41.7%, in the GnRHa, GnRHant, combination (lng) and combination (sht) groups, respectively. Pretreatment with GnRHa, GnRHant and combination (lng) significantly protected the primordial follicles from destruction by preserving 57.6%, 63.4%, 87.1% and 60.4% of the follicles, respectively.

CONCLUSIONS

The combination of a GnRH agonist with antagonist completely prevented the flare-up effect and enhanced the protective effect of the ovary from cisplatin-induced gonadotoxicity in rats.

Multiple approaches for individualized fertility protective therapy in cancer patients

In the last decade, fertility preservation has risen as a major field of interest, creating new interactions between oncologists and gynecologists. Various options, such as cryopreservation of ovarian tissue, have been developed and are currently routinely proposed in many centers. However, many of the options remain experimental and should be offered to patients only after adequate counseling. This paper addresses the efficiency and the potential of the different fertility preservation approaches.