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

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.

Syringic acid alleviates cisplatin-induced ovarian injury through modulating endoplasmic reticulum stress, inflammation and Nrf2 pathway

BACKGROUND

Reproductive toxicity is one of the most important side effects of cisplatin (CIS) and leading to discontinuation of treatment. Syringic acid (SA) is a phenolic acid whose industrial use has increased in recent years due to its antioxidant properties. Recent reports highlight the importance of the supressed Nrf2 pathway in the molecular pathogenesis of CIS toxicity. Therefore, this study aimed to evaluate the therapeutic effect of SA on CIS-induced ovotoxicity through the Nrf2 pathway for the first time.

MATERIAL AND METHODS

Thirty female rats were divided into 5 groups: control, CIS, CIS+SA (5 and 10 mg/kg) and only SA (per se, 10 mg/kg). CIS was administered intraperitoneally at a dose of 5 mg/kg on the 1st day, injections of SA followed by three consecutive days in the rats. Serum anti-mullerian hormone (AMH) levels and ovarian oxidative stress (OS), inflammation, endoplasmic reticulum stress (ERS), apoptosis and Nrf2 pathway markers were determined colorimetrically. Histopathological examinations of the ovaries with hematoxylin and eosin staining were also used to evaluate CIS-induced ovotoxicity.

RESULTS

The CIS treatment depleted serum AMH levels, caused histopathological findings and increased OS, inflammation, ERS and apoptosis levels in ovarian tissue. However, treatments with SA significantly ameliorated CIS-induced biochemical and histopathological changes by activating Nrf2 pathway.

CONCLUSION

The promising adjuvant potential of SA to alleviate CIS-related ovarian damage should be supported by more comprehensive studies.

Evaluation of the therapeutic effects of arbutin on cisplatin-induced ovarian toxicity in rats through endoplasmic reticulum stress and Nrf2 pathway

Arbutin (ARB) is a glycosylated hydroquinone with potent antioxidant effects. Although cisplatin (CP) is widely used in chemotherapy, its toxicity in healthy tissues, including ovotoxicity, is an insurmountable problem. This study aimed to evaluate the therapeutic effect of ARB against CP-related ovototoxicity by including nuclear factor erythroid 2-related factor 2 (Nrf2) pathway in rats for the first time. Rats treated one dose of CP (5 mg/kg) on the first day, followed by ARB (5 and 10 mg/kg) for three days. Serum reproductive hormone levels were determined using ELISA kits. Oxidative stress (OS), inflammation, endoplasmic reticulum stress (ERS) and apoptosis markers in ovarian tissue were also determined colorimetrically. In addition, how CP affects Nrf2 pathway and the effect of ARB on this situation were also addressed. ARB treatment reduced the levels of markers of OS, inflammation, ERS and apoptosis in ovarian tissue of CP-stimulated animals. ARB regenerated the depleted antioxidant system by triggering Nrf2 pathway in the ovarian tissues of animals stimulated by CP. Histological findings also supported the therapeutic efficacy of ARB. The results indicate that ARB may have therapeutic effects against CP-induced reproductive toxicity with its Nrf2 activator potential. ARB should be tested in more extensive studies as a new generation chemopreventive candidate molecule.

Effects of erythropoietin on ischaemia-reperfusion when administered before and after ovarian tissue transplantation in mice

RESEARCH QUESTION

Is the optimal timing for administering erythropoietin to minimize ischaemic injury in ovarian tissue transplantation before ovary removal for cryopreservation and subsequent transplantation or after transplantation?

DESIGN

Thirty Swiss mice (nu/nu) were divided into three groups: treatment control group (n = 10); erythropoietin before harvesting group (EPO-BH) (n = 10) and erythropoietin after transplantation group (EPO-AT) (n = 10). Animals underwent bilateral ovariohysterectomy and their hemiovaries were cryopreserved by slow freezing. At the same time, previously cryopreserved hemiovaries were transplanted subcutaneously in the dorsal region. Erythropoietin (250 IU/kg) and sterile 0.9% saline solution were administered every 12/12 h over 5 consecutive days in the EPO-AT and EPO-BH groups, respectively.

RESULTS

Administration of erythropoietin in the EPO-AT group improved the viability of ovarian follicles, reducing degeneration and increasing the number of morphologically normal growing follicles at 14 days after transplantation compared with the EPO-BH group (P = 0.002). This group also showed higher percentages of proliferative follicles at 7 days after transplantation (P ≤ 0.03), increased blood vessel count (P ≤ 0.03) and greater tissue area occupied by blood vessels at days 7 and 14 after transplantation (P ≤ 0.03), compared with hormone administration before cryopreservation (EPO-BH group) and the treatment control group. Additionally, treatment with erythropoietin before or after transplantation reduced fibrotic areas at 7 days after transplantation (P = 0.004).

CONCLUSION

Erythropoietin treatment after transplantation reduced ischaemic damage in transplanted ovarian tissue, increased angiogenesis, maintenance of ovarian follicle proliferation and reduced fibrosis areas in the grafted tissue.

Fertility-enhancing effects of inositol & vitamin C on cisplatin induced ovarian and uterine toxicity in rats via suppressing oxidative stress and apoptosis

Cisplatin can lead to infertility due to its negative impact on the uterus and ovaries. This study aimed to explore the effects of Inositol and vitamin C on cisplatin-induced infertility. Forty-eight adult female Wistar rats were divided into eight groups (N = 6) and orally treated for 21 days. The treatments were as follows: negative control (saline), positive control (saline and cisplatin injected into the abdomen on day 15), T1-T3: rats given vitamin C (150 mg/kg), Inositol (420 mg/kg), and vitamin C + Inositol, respectively, along with cisplatin injected into the abdomen on day 15, T4-T6: rats given only vitamin C, Inositol, and vitamin C + Inositol, respectively. Vitamin C and Inositol enhanced cisplatin-induced histopathological improvements in the uterus and ovaries, raising progesterone and estradiol serum levels. Furthermore, the supplements enhanced ESR1 gene expression in the uterus and ovary, reducing uterine and ovarian apoptosis caused by cisplatin through modulation of caspase 3, 8, and Bcl-2 gene levels. These substances decreased ovarian and uterine malondialdehyde levels, boosted total antioxidant capacity and superoxide dismutase, and alleviated oxidative stress. The findings reveal that vitamin C and Inositol shield against cisplatin-related infertility by reducing oxidative stress and apoptosis in the uterus and ovaries.

The therapeutic effect of silibinin against 5-fluorouracil-induced ovarian toxicity in rats

5-Fluorouracil (5-FU) is a fluoropyrimidine group antineoplastic drug with antimetabolite properties and ovotoxicity is one of the most important side effects. Silibinin (SLB) is a natural compound that is used worldwide and stands out with its antioxidant and anti-inflammatory properties. The aim of this study was to evaluate the therapeutic effect of SLB in 5-FU-induced ovototoxicity using biochemical and histological analysis. This study was carried out in five main groups containing six rats in each group: control, SLB (5 mg/kg), 5-FU (100 mg/kg), 5-FU + SLB (2.5 mg/kg), and 5-FU + SLB (5 mg/kg). The levels of ovarian malondialdehyde (MDA), total oxidant status (TOS), total antioxidant status (TAS), superoxide dismutase (SOD), catalase (CAT), 8-hydroxy-2'-deoxyguanosine (8-OHdG), tumor necrosis factor-alpha (TNF-α), myeloperoxidase (MPO), and caspase-3 were determined using spectrophotometric methods. Hematoxylin and eosin staining method was employed for histopathological examination. MDA, TOS, 8-OHdG, TNF-α, MPO, and caspase-3 levels in 5-FU group were significantly increased compared with the control group, while the levels of TAS, SOD, and CAT were decreased (p < 0.05). SLB treatments statistically significantly restored this damage in a dose-dependent manner (p < 0.05). Although vascular congestion, edema, hemorrhage, follicular degeneration, and leukocyte infiltration were significantly higher in the 5-FU group compared with the control group, SLB treatments also statistically significantly restored these damages (p < 0.05). In conclusion, SLB has a therapeutic effect on the ovarian damage induced by 5-FU via decreasing the levels of oxidative stress, inflammation, and apoptosis. It may be helpful to consider the usefulness of SLB as an adjuvant therapy to counteract the side effects of chemotherapy.

Melatonin Mitigates Cisplatin-Induced Ovarian Dysfunction via Altering Steroidogenesis, Inflammation, Apoptosis, Oxidative Stress, and PTEN/PI3K/Akt/mTOR/AMPK Signaling Pathway in Female Rats

Ovarian damage and fertility impairment are major side effects of chemotherapy in pre-menopausal cancer patients. Cisplatin is a widely used chemotherapeutic drug. The present study was designed to assess the ameliorative effects of melatonin as an adjuvant for fertility preservation. Thirty-two adult female Wistar rats were divided randomly into four equal groups: Control, Melatonin, Cisplatin (CP) treated, and CP + Melatonin treated. The cisplatin-treated group showed decreased body and ovarian weights, decreased serum E2 and AMH, increased serum LH and FSH, reduced ovarian levels of SOD, CAT, GSH, and TAC, and increased ovarian MDA. The histopathological examination of the cisplatin-treated group showed deleterious changes within ovarian tissue in the form of damaged follicles and corpus luteum, hemorrhage, and inflammatory infiltrates with faint PAS reaction in zona pellucida, increased ovarian collagen deposition, and marked expression of caspase-3 immune reaction in granulosa and theca cells, stroma, and oocytes. Alongside, there was a significant downregulation in the mRNA expression of steroidogenic enzymes, IL10, AMPK, PI3K, AKT, mTOR, and PTEN, while TGF-β1, IL1β, IL6, TNF-α, NF-Kβ, P53, p38-MAPK, JNK, and FOXO3 mRNA expressions were upregulated in cisplatin-treated rats' ovarian tissue. Coadministration of cisplatin-treated rats with melatonin reversed these changes significantly. In conclusion, melatonin's antioxidant, anti-inflammatory, and anti-apoptotic activities could modulate ovarian disturbances induced by cisplatin and preserve fertility.

Protective effect of adenosine triphosphate against sunitinib-related skin damage in rats

Cutaneous side effects associated with sunitinib use are a major problem in patients receiving cancer treatment. The aim of this study was to investigate the protective effect of adenosine triphosphate (ATP) against possible skin damage resulting from sunitinib use in rats. Thirty Albino Winstar rats were divided into the following three groups: healthy controls (HCs, n = 10), sunitinib (SUN, n = 10), and sunitinib + ATP (SAT, n = 10). ATP was injected intraperitoneally at a dose of 2 mg/kg. One hour subsequent to the administration of ATP and 0.9% NaCl, the SAT and SUN groups were orally administered a dose of 25 mg/kg sunitinib to the stomach. Macroscopic evaluation of the skin indicated lower levels of skin damage in the SAT group than in the SUN group. As an indicator of oxidative stress, malondialdehyde (MDA), total oxidant status (TOS), and oxidative stress index (OSI) levels were significantly higher in the SUN group than in the HC group, while total glutathione (tGSH) and total antioxidant status (TAS) levels were significantly lower. However, MDA, TOS, and OSI levels were significantly lower in the SAT group than in the SUN group, while tGSH and TAS levels were significantly higher. Histopathological examination revealed keratin plugs with edema, vasopathology, and inflammatory cell infiltration in the SUN group. The SAT group showed less necrotic epithelium, keratin plugs, edema, and vasopathology than the SUN group. ATP can be effective in preventing skin damage caused by sunitinib use by reducing oxidative stress.

Impact of coadministration of apigenin and bone marrow stromal cells on damaged ovaries due to chemotherapy in rat: An experimental study

BACKGROUND

Apigenin is a plant-derived flavonoid with antioxidative and antiapoptotic effects. Bone marrow stromal cells (BMSCs) are a type of mesenchymal stem cells (MSCs) that may recover damaged ovaries. It seems that apigenin may promote the differentiation of MSCs.

OBJECTIVE

The aim of this study was to investigate the effect of coadministration of apigenin and BMSCs on the function, structure, and apoptosis of the damaged ovaries after creating a chemotherapy model with cyclophosphamide in rat.

MATERIALS AND METHODS

For chemotherapy induction and ovary destruction, cyclophosphamide was injected intraperitoneally to 40 female Wistar rats (weighing 180-200 gr, 10 wk old) for 14 days. Then, the rats were randomly divided into four groups (n = 10/each): control, apigenin, BMSCs and coadministration of apigenin and BMSCs. Injection of apigenin was performed intraperitoneally and BMSC transplantation was performed locally in the ovaries. The level of anti-mullerian hormone serum by ELISA kit, the number of oocytes by superovulation, the number of ovarian follicles in different stages by H&E staining, and the expression of ovarian Bcl-2 and Bax proteins by western blot were assessed after four wk.

RESULTS

The results of serum anti-mullerian hormone level, number of oocytes and follicles, and Bcl-2/Bax expression ratio showed that coadministration of apigenin and BMSCs significantly recovered the ovarian function, structure, and apoptosis compared to the control, BMSC, and apigenin groups (p < 0.001).

CONCLUSION

The results suggest that the effect of coadministration of apigenin and BMSCs is maybe more effective than the effect of their administrations individually on the recovery of damaged ovaries following the chemotherapy with cyclophosphamide in rats.

Rapamycin preserves the primordial follicle pool during cisplatin treatment in vitro and in vivo

Rapamycin has been proven to effectively inhibit the activation of primordial follicles while cisplatin-induced the loss of primordial follicles due to the over-activation of the primordial follicle stockpile. Whether rapamycin could inhibit the loss of primordial follicles induced by cisplatin is still unknown. The ovaries of neonatal Sprague Dawley rats were cultured in vitro in different doses of rapamycin (0.08, 0.16, and 0.32 μg/ml) and cisplatin (0.1, 0.4, and 0.8 μg/ml). The immature BALB/c mice were administered cisplatin with or without rapamycin by intraperitoneal injection. Ovaries were collected to analyze the histomorphology, the messenger RNA (mRNA) expression of anti-Mullerian hormone (AMH), growth differentiation factor 9 (GDF9), and bone morphogenetic protein 15 (BMP15) and the expression of key proteins of mammalian target of rapamycin (mTOR) pathway. Growing follicle counts of ovaries cultured in vitro in the R0.16 and R0.32 groups were decreased and the ratio of growing to primordial follicles was also decreased in a dose-dependent manner. In the C0.8 group, growing follicles were decreased compared with the other groups while the ratio was substantially increased in the C0.4 and C0.8 group. Co-treatment attenuated primordial follicle loss and reduced the upregulated ratio induced by cisplatin. Ovarian follicle dynamics in vivo was consistent with the in vitro results. Primordial follicles counts were statistically increased and the ratio was reduced in the rapamycin group compared with the control group. Primordial follicle counts were dramatically reduced in the cisplatin group whereas co-treatment with rapamycin slightly recovered its counts. There was no obvious difference in the number of growing follicles between the cisplatin group and other groups. The ratio was significantly increased in cisplatin-treated mice whereas decreased in the co-treatment group. The apoptosis rate of antral follicles in cisplatin-treated mice was higher than the other groups while the apoptosis rate was decreased in the co-treatment group in vivo. Compared with the control and rapamycin group, the mRNA expression of AMH, GDF9, and BMP15 were downregulated in the cisplatin group. The co-treatment group recovered the mRNA expression of BMP15. In addition, the expression of key protein of mTOR pathway rpS6 and its phosphorylated forms were increased in the cisplatin-treated group while co-treatment decreased their expression. Rapamycin attenuated the loss of primordial follicles induced by cisplatin through the inhibitory effect of rapamycin on the mTOR pathway. These results suggest that rapamycin may be an effective drug for the protection of ovarian function during chemotherapy.

Investigation of the preventive effects of dehydroepiandrosterone (DHEA) and Caffeic acid phenethyl ester (CAPE) on cisplatin-induced ovarian damage in rats

To investigate whether Dehydroepiandrosterone (DHEA) and Caffeic acid phenethyl ester (CAPE) had any preventive effect against the ovarian damage caused by cisplatin (CP) (cis-diamminedichloroplatinum) in rats. On the first day ovaries were removed, Anti-Müllerian hormone (AMH) was measured (Group1, n:6), in the other groups 7.5 mg/kg cisplatin was administered intraperitoneally. In Group 2 (n = 6), 0.1 ml saline, in Group 3 (n = 5), 20 umol/kg CAPE, in Group 4 (n = 7), DHEA 6 mg/kg were administered every day. On the 10th day, ovaries were removed, AMH was measured. Ovary reserve (primordial/primary/secondary/tertiary/atretic follicles, AMH), ovarian damage scores (follicular degeneration, congestion, hemorrhage, edema, inflammation) were compared. The number of tertiary follicles were statistically high in the CAPE group (p = .015), the inflammation score in the DHEA group (p = .012), AMH level (p = .009) in the control group. The lowest number of atretic follicles (AF) was in the control group, while the highest number of AF was in the DHEA group (p = .002). Significant decreases in AF were the case in the cisplatin and DHEA groups compared to the control group (p < .008). The AMH values had the highest positive correlation with the number of primordial follicles and the highest negative correlation with the number of AF. The cut off point for AMH was 1.57 ng/ml as an indicator of low ovarian reserve. Cisplatin causes total damage and increased numbers of AF on the ovary. Depending on this, AMH levels fall. These negative effects of cisplatin are not obstructed by CAPE or DHEA, and may even be increased by DHEA.

Consequences of chemotherapeutic agents on primordial follicles and future clinical applications

The ovarian reserve is necessary for female fertility and endocrine health. Commonly used cancer therapies diminish the ovarian reserve, thus, resulting in primary ovarian insufficiency, which clinically presents as infertility and endocrine dysfunction. Prepubertal children who have undergone cancer therapies often experience delayed puberty or cannot initiate puberty and require endocrine support to maintain a normal life. Thus, developing an effective intervention to prevent loss of the ovarian reserve is an unmet need for these cancer patients. The selection of adjuvant therapies to protect the ovarian reserve against cancer therapies underlies the mechanism of loss of primordial follicles (PFs). Several theories have been proposed to explain the loss of PFs. The "burn out" theory postulates that chemotherapeutic agents activate dormant PFs through an activation pathway. Another theory posits that chemotherapeutic agents destroy PFs through an "apoptotic pathway" due to high sensitivity to DNA damage. However, the mechanisms causing loss of the ovarian reserve remains largely speculative. Here, we review current literature in this area and consider the mechanisms of how gonadotoxic therapies deplete PFs in the ovarian reserve.

The Impact of Chemotherapy on the Ovaries: Molecular Aspects and the Prevention of Ovarian Damage

Cancer treatment, such as chemotherapy, induces early ovarian follicular depletion and subsequent infertility. In order to protect gametes from the gonadotoxic effects of chemotherapy, several fertility preservation techniques—such as oocyte or embryo cryopreservation with or without ovarian stimulation, or cryopreservation of the ovarian cortex—should be considered. However, these methods may be difficult to perform, and the future use of cryopreserved germ cells remains uncertain. Therefore, improving the methods currently available and developing new strategies to preserve fertility represent major challenges in the area of oncofertility. Animal and ovarian culture models have been used to decipher the effects of different cytotoxic agents on ovarian function and several theories regarding chemotherapy gonadotoxicity have been raised. For example, cytotoxic agents might (i) have a direct detrimental effect on the DNA of primordial follicles constituting the ovarian reserve and induce apoptosis; (ii) induce a massive growth of dormant follicles, which are then destroyed; or (ii) induce vascular ovarian damage. Thanks to improvements in the understanding of the mechanisms involved, a large number of studies have been carried out to develop molecules limiting the negative impact of chemotherapy on the ovaries.

Adjuvant gonadotropin-releasing hormone analogues for the prevention of chemotherapy-induced premature ovarian failure in premenopausal women

BACKGROUND

This is an update of the original review published in the Cochrane Database of Systematic Reviews 2011, Issue 11, and updated in 2015, Issue 4.Chemotherapy has significantly improved prognosis for women with malignant and some non-malignant conditions. This treatment, however, is associated with ovarian toxicity. The use of gonadotropin-releasing hormone (GnRH) analogues, both agonists and antagonists, may have a protective effect on the ovaries. The primary mechanism of action of GnRH analogues is to suppress the gonadotropin levels to simulate pre-pubertal hormonal milieu and subsequently prevent primordial follicles from maturation and therefore decrease the number of follicles that are more vulnerable to chemotherapy.

OBJECTIVES

To assess the efficacy and safety of GnRH analogues given before or in parallel to chemotherapy to prevent chemotherapy-related ovarian damage in premenopausal women with malignant or non-malignant conditions.

SEARCH METHODS

The search was run for the original review in July 2011, and for the first update in July 2014. For this update we searched the following databases in November 2018: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and the Chinese Biomedicine Database (CBM).

SELECTION CRITERIA

Randomised controlled trials (RCTs), in all languages, which examined the effect of GnRH analogues for chemotherapy-induced ovarian failure in premenopausal women, were eligible for inclusion in the review.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed trial quality using the Cochrane 'Risk of bias' tool. We analysed binary data using risk ratios (RRs) with 95% confidence intervals (CI) and for continuous data, we used the standardized mean difference (SMD) to combine trials. We applied the random-effects model in our analyses. We used the GRADE approach to produce a 'Summary of findings' table for our main outcomes of interest.

MAIN RESULTS

We included 12 RCTs involving 1369 women between the ages of 12 and 51.1 years. Participants were diagnosed with breast malignancy, ovarian malignancy, or Hodgkin's lymphoma, and most of them received alkylating, or platinum complexes, based chemotherapy. The included studies were funded by a university (n = 1), research centres (n = 4), and pharmaceutical companies (n = 1). Trials were at high or unclear risk of bias.Comparison 1: GnRH agonist plus chemotherapy versus chemotherapy aloneThe incidence of menstruation recovery or maintenance was 178 of 239 (74.5%) in the GnRH agonist group and 110 of 221 (50.0%) in the control group during a follow-up period no longer than 12 months (RR 1.60, 95% CI 1.14 to 2.24; 5 studies, 460 participants; I² = 79%; low-certainty evidence), with an overall effect favouring treatment with GnRH agonist (P = 0.006). However, we observed no difference during a follow-up period longer than 12 months between these two groups (P = 0.24). In the GnRH agonist group, 326 of 447 participants had menstruation recovery or maintenance (72.9%) in comparison to the control group, in which 276 of 422 participants had menstruation recovery or maintenance (65.4%) during a follow-up period longer than 12 months (RR 1.08, 95% CI 0.95 to 1.22; 8 studies, 869 participants; I² = 56%; low-certainty evidence).The incidence of premature ovarian failure was 43 of 401 (10.7%) in the GnRH agonist group and 96 of 379 (25.3%) in the control group (RR 0.44, 95% CI 0.31 to 0.61; 4 studies, 780 participants; I² = 0%; moderate-certainty evidence), with an overall effect favouring treatment with GnRH agonist (P < 0.00001).The incidence of pregnancy was 32 of 356 (9.0%) in the GnRH agonist group and 22 of 347 (6.3%) in the control group (RR 1.59, 95% CI 0.93 to 2.70; 7 studies, 703 participants; I² = 0%; low-certainty evidence), with no difference between groups (P = 0.09). However, we are cautious about this conclusion because there were insufficient data about whether the participants intended to become pregnant.The incidence of ovulation was 29 of 47 (61.7%) in the GnRH agonist group and 12 of 48 (25.0%) in the control group (RR 2.47, 95% CI 1.43 to 4.26; 2 studies, 95 participants; I² = 0%; low-certainty evidence) with an overall effect favouring treatment with GnRH (P = 0.001).The most common adverse effects of GnRH analogues included hot flushes, vaginal dryness, urogenital symptoms, and mood swings. The pooled analysis of safety data showed no difference in adverse effects between GnRH agonist group and control group.Comparison 2: GnRH agonist-antagonist cotreatment plus chemotherapy versus chemotherapy aloneOnly one RCT discussed GnRH agonist-antagonist cotreatment. The limited evidence showed the incidence of menstruation recovery or maintenance was 20 of 25 (80%) in both cotreatment group and control group during a 12-month follow-up period (RR 1.00, 95% CI 0.76 to 1.32; 50 participants; very low-certainty evidence), with no difference between groups (P = 1.00). In the cotreatment group, 13 of 25 participants had menstruation recovery or maintenance (52.0%) in comparison to the control group, in which 14 of 25 participants had menstruation recovery or maintenance (56.0%) during a follow-up period longer than 12 months (RR 0.93, 95% CI 0.56 to 1.55; 50 participants; very low-certainty evidence), with no difference between groups (P = 0.78). The incidence of pregnancy was 1 of 25 (4.0%) in the cotreatment group and 0 of 25 (0%) in the control group (RR 3.00, 95% CI 0.13 to 70.30; 50 participants; very low-certainty evidence), with no difference between groups (P = 0.49).

AUTHORS' CONCLUSIONS

GnRH agonist appears to be effective in protecting the ovaries during chemotherapy, in terms of maintenance and resumption of menstruation, treatment-related premature ovarian failure and ovulation. Evidence for protection of fertility was insufficient and needs further investigation. Evidence was also insufficient to assess the effect of GnRH agonist and GnRH antagonist cotreatment on ovarian protection against chemotherapy. The included studies differed in some important aspects of design, and most of these studies had no age-determined subgroup analysis. Large and well-designed RCTs with longer follow-up duration should be conducted to clarify the effects of GnRH analogues in preventing chemotherapy-induced ovarian failure, especially on different age groups or different chemotherapy regimens. Furthermore, studies should address the effects on pregnancy rates and anti-tumour therapy.