Melatonin activates Nrf2/HO-1 signalling pathway to antagonizes oxidative stress-induced injury via melatonin receptor 1 (MT1) in cryopreserved mice ovarian tissue.

Our previous research has shown that melatonin (MLT) can reduce cryopreserved ovarian damage in mice. Yet, the molecular mechanism of MLT protection is still unclear. Some studies have shown that melatonin receptor 1 (MT1) is very important for animal reproductive system. To evaluate whether MLT exerts its protective effect on cryopreserved mice ovarian tissue via MT1, we added antagonist of MT1/MT2 (Luzindor) or antagonist of MT2 (4P-PDOT) to the freezing solution, followed by cryopreservation and thawing of ovarian tissue. The levels of total superoxide dismutase (T-SOD), catalase (CAT), nitric oxide (NO) and malondialdehyde (MDA) were detected. Besides, by using RT-PCR and Western blotting, the expression of Bcl-2, Bax and Nrf2/HO-1 signalling pathway-related proteins was detected. These findings demonstrated that compared with the melatonin group, the addition of Luzindor increased apoptosis, NO and MDA activities, decreased CAT and T-SOD activities and inhibited Nrf2/HO-1 signalling pathway. In conclusion, melatonin can play a protective role in cryopreserved ovarian tissue of mice through MT1 receptor.

The novel HLA-A*24:627 allele, identified by Sanger dideoxy nucleotide sequencing in a Chinese individual.

The HLA-A*24:627 allele differs from HLA-A*24:02:01:01 by one nucleotide substitution in codon 172 in exon 2.

Plasma-derived from human umbilical cord blood restores ovarian function and improves serum reproductive hormones levels in mice with premature ovarian insufficiency (POI) through cytokines and growth factors.

Premature ovarian insufficiency (POI) patients experience a decline in ovarian function and a reduction in serum reproductive hormones, leading to a significant impact on the outcomes of assisted reproductive technology. Despite the absence of an effective clinical treatment to restore fertility in POI patients, recent research has indicated that cord blood plasma (CBP) derived from human umbilical cord blood (hUCB) may offer therapeutic benefits for various degenerative diseases. The primary aim of this study is to explore approaches for enhancing ovarian function and serum reproductive hormones through the administration of CBP in a murine model. Initially, hUCB was utilized to obtain CBP (CBP), which was subsequently analyzed for cytokine and growth factor profiles in comparison to adult blood plasma (ABP) by use of flow cytometry. Subsequently, POI mouse models were established through the induction of 4-vinylcyclohexene diepoxide, followed by the injection of CBP into the tail. At 7, 14, and 21 days posttreatment, mouse ovaries and blood were collected, and their estrus cycle, body weight, and ovarian weights were evaluated using precise electronic balance. Finally, ovarian morphology and follicle number were assessed through HE staining, while serum levels of anti-Müllerian hormone (AMH), estradiol (E2) and follicle-stimulating hormone (FSH) were determined by ELISA. Our study revealed that individuals with CBP exhibited significantly lower concentrations of proinflammatory cytokines, including IL-ß (p < 0.01) and IL-2 (p < 0.05), while displaying elevated levels of anti-inflammatory cytokines and chemokines, such as IL-2, IL-4, IL-6, IL-8, IL-12P70, IL-17A, IP-10, interferon-γ, and tumor necrosis factor-α (p < 0.01). Furthermore, CBP demonstrated remarkably higher levels of growth factors, including transforming growth factor-ß1, vascular endothelial growth factor, and insulin-like growth factor-1 (p < 0.01) than ABP. Notably, our investigation also revealed that CBP restored the content of serum reproductive hormones, such as AMH, E2, and FSH (p < 0.05), and increased the number of primordial and primary follicles (p < 0.01) and decreased the number of luteal and atretic follicles (p < 0.01) in vivo. Our findings suggested that CBP-secreted cytokines and growth factors could be restored POI ovarian function, enhanced serum reproductive hormones and rescued follicular development in vivo. These findings further support the potential of CBP as a promising strategy in clinical applications for POI related infertility.

Effects of sericin on oxidative stress and PI3K/AKT/mTOR signal pathway in cryopreserved mice ovarian tissue.

Ovarian tissue cryopreservation is an effective fertility protective strategy for preadolescent female cancer patients, whose tumor treatment cannot be delayed. In the present study, the effects of sericin, as an antioxidant, on mice ovarian tissue freezing and thawing were investigated. Mice ovarian tissues were cryopreserved and thawed in medium containing 0.5% or 1%sericin (w/v), and 0.1 mM melatonin. Then, the follicular morphology was observed. The levels of antioxidant enzymes were determined, including glutathione (GSH), glutathione peroxidase (GSH-Px), total superoxide dismutase (T-SOD), total antioxidant capacity (T-AOC) and catalase (CAT). Moreover, the levels of nitric oxide (NO), malondialdehyde (MDA) and lactate dehydrogenase (LDH) were also tested. Besides, apoptosis-related proteins Bcl-2 and Bax were determined. Our results showed that 1% sericin maintained follicular morphology, inhibited apoptosis, decreased MDA and NO levels, and boosted endogenous antioxidant enzyme levels, while had no significant effect on LDH levels. Furthermore, these effects may be related with the activation of the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of Rapamycin (mTOR) signaling pathway, as demonstrated by increased PI3K, p-AKT and mTOR levels. These findings demonstrate that 1% sericin may reduce oxidative stress and protect ovarian tissues during freezing and thawing via PI3K/AKT/mTOR signaling pathway.

Bilateral varicocele leads to ferroptosis, pyroptosis and necroptosis of human spermatozoa and affects semen quality in infertile men.

Purpose: This study explored the effects of bilateral varicocele on male semen quality in infertile men and the molecular mechanisms involving ferroptosis, pyroptosis and necroptosis signaling pathways. Methods: Totally, 20 healthy males and 26 patients with bilateral varicocele receiving infertility treatment were enrolled. Semen samples were collected. Basic semen parameters, acrosome integrity and membrane integrity, mitochondrial membrane potential (MMP) and apoptosis rate were compared. Levels of reactive oxygen species (ROS), iron, glutathione (GSH), total superoxide dismutase (T-SOD), and, Catalase (CAT), were detected in human seminal plasma. Relative mRNA expression of Ca 2+-independent phospholipases A2 beta (iPLA 2ß), P53, Zinc finger E-box binding homeobox 1 (ZEB1) and GSH-dependent peroxidase 4 (GPX4) were evaluated. Relative protein expression was determined for GPX4, receptor interacting serine/threonine kinase 1 (RIPK1) and receptor interacting serine/threonine kinase 3 (RIPK3), as well as pyroptosis markers of Gasdermin E (GSDME) and heat shock protein 90 (HSP 90). Results: The results revealed that the bilateral varicocele group had significantly higher abnormalities (sperm progressive rate and sperm motility) compared to the control group. Meanwhile, compared to control group, GSH, T-SOD, and CAT levels were reduced in the bilateral varicocele group (p < 0.05). However, the level of ROS and iron were significantly increased (p < 0.05). Relative mRNA expression of P53, iPLA 2ß, ZEB1, and GPX4 were reduced. In addition, ROS exposure activated ferroptosis-related signal pathways. RIPK1, RIPK3, GSDME and HSP 90 were increased in bilateral varicocele group. ROS exposure affected signaling pathways related to ferroptosis, necrosis and pyroptosis in human spermatozoa. Conclusion: Bilateral varicocele leads to ferroptosis, pyroptosis and necroptosis of human spermatozoa and affects semen quality in infertile men.

Therapeutic Effect of Melatonin in Premature Ovarian Insufficiency: Hippo Pathway Is Involved.

Objective: Premature ovarian insufficiency (POI) is a female reproductive disorder of unknown etiology with no definite pathogenesis. Melatonin (MT) is an endogenous hormone synthesized mainly by pineal cells and has strong endogenous effects in regulating ovarian function. To systematically explore the pharmacological mechanism of MT on POI therapy, a literature review approach was conducted at the signaling pathways level. Methods: Relevant literatures were searched and downloaded from databases, including PubMed and China National Knowledge Infrastructure, using the keywords "premature ovarian insufficiency," "Hippo signaling pathways," and "melatonin." The search criteria were from 2010 to 2022. Text mining was also performed. Results: MT is involved in the regulation of Hippo signaling pathway in a variety of modes and has been correlated with ovarian function. Conclusions: The purpose of this review is to summarize the research progress of Hippo signaling pathways and significance of MT in POI, the potential crosstalk between MT and Hippo signaling pathways, and the prospective therapy.

Effect of dominant follicle status at the time of retrieval on the clinical outcomes in natural cycle IVF combined with immature oocyte treatment.

OBJECTIVE: It is commonly believed that the oocytes from small follicles are unhealthy when a dominant follicle (DF) is recruited in the ovaries, especially when the DF is ovulated. This study aims to confirm whether the presence or ovulation of DF at the time of retrieval affects the clinical outcome of the natural cycle IVF with in vitro maturation (NC-IVF/M) treatment. METHODS: Data were collected from 446 women with regular menstrual cycle and 536 retrieval cycles using NC-IVF/M treatment. The cycles were divided into three groups based on the results of the oocyte retrieval cycle. Group A covers the collection of oocytes from the DF and small follicles; Group B incorporates failed oocyte retrieval from DF and then the oocytes are retrieved only from small follicles; and Group C includes the retrieval of oocytes only from small follicles accompanied with an ovulated DF. Furthermore, Group B and C have subgroups to include whether in vivo matured oocytes were obtained from small follicles. Following aspiration of DF and small follicles, mature oocytes were inseminated on the date of retrieval by intracytoplasmic sperm injection (ICSI) and the immature oocytes were matured in vitro. If the immature oocytes were matured in vitro, they were inseminated using ICSI, and then the embryos obtained from in vivo and in vitro matured oocytes were transferred accordingly. RESULTS: The oocytes from DF were successfully retrieved in 445 cycles (83.0%), failed to be retrieved in 54 cycles (10.1%) and ovulated in 37 cycles (6.9%). In Group A, an average of 2.0 ± 1.7 mature oocytes were retrieved, which was significantly higher than the average of Group B, with 1.3 ± 1.3 matured oocytes and Group C, with an average of 1.1 ± 1.5 matured oocytes (P < 0.01). However, the average number of immature oocytes retrieved from each group show no difference among the three groups. There was no significant difference in maturation rates of immature oocytes, fertilization rates among the three groups. The clinical pregnancy rate per transfer cycle is 34.5%, 34.6% and 25.7% in Group A, B and C, respectively. No significant differences were observed in embryonic development and implantation capacity in Group B and C in comparison to Group A. And there was no significant difference in clinical pregnancy, implantation, live birth and miscarriage rates among the three groups. No significant differences were observed in the developmental and implantation capacity according to with or without in vivo matured oocytes were retrieved in Group B and Group C. CONCLUSION: The presence or ovulation of the dominant follicle from the ovaries does not significantly influence the developmental and implantation capacity of immature oocytes retrieved from small follicles, suggesting that NC-IVF/M is a promising treatment option for women without ovarian stimulation.

The Predictive Levels of Serum Anti-Müllerian Hormone and the Combined Index of the Number of Retrieved Oocytes and Good-Quality Embryos in Advanced-Age Infertile Women.

The primary objective of the study was to assess the values of serum anti-Müllerian hormone (AMH) levels and the combined index for the prediction of number of oocytes retrieved (NOR) and number of good-quality embryos (GQE) in infertile women undergoing IVF/ICSI treatment. A group of 521 infertile women aged 21-46 years were recruited as subject in this study. Serum AMH, hormones, and antral follicle count (AFC) were measured. The infertile women were categorized into three groups: 21-34 years (reproductive age), 35-39 years (reproductive age), and 40-46 years (advanced-age infertile). The predictive accuracy of variables was analyzed by the receiver operating characteristic (ROC) curve. AFC, AFC/age ratio, AMH/age ratio, and ovarian response prediction index (ORPI) decreased gradually, while AMH decreased significantly with increase in age. Moreover, NOR and GQE were positively correlated with AFC, AMH, AFC/age ratio, AMH/age ratio, and ORPI (P < 0.001). A statistical significance was observed in predicted oocyte retrieval including AMH, AMH/age ratio, and ORPI between 21-34 years and 35-46 years; especially in the 35-46 years group, these variables reached a "high" grade in the diagnostic accuracy because area under curve (AUC) ranged from 0.982 to 0.988 significantly. No statistical significance was observed for FSH, AMH, AFC, and related combined index predicting GQE. The predictive value of AFC and AFC/age ratio was limited regarding oocyte retrieval; however, AMH, AMH/age ratio, and ORPI concurrently had an excellent value for predicting NOR in reproductive-age women, especially in advanced-age infertile women.

Effects of embryo density on cell number of day 3 embryos cultured in a 30-µl drop: a retrospective cohort study.

For individual cultures, findings on regulating embryo density by changing the microdrop volume are contradictory. The aim of this study was to investigate the relationship between embryo density and the developmental outcome of day 3 embryos after adjusting covariates. In total, 1196 embryos from 206 couples who had undergone in vitro fertilization treatment were analyzed retrospectively. Three embryo densities were used routinely, i.e. one embryo in a drop (30 µl/embryo), two embryos in a drop (15 µl/embryo) and three embryos in a drop (10 µl/embryo). Embryo quality on day 3 was evaluated, both the cell number of day 3 embryos and the proportion of successful implantations served as endpoints. Maternal age, paternal age, antral follicles and level of anti-Müllerian hormone, type of infertility, controlled ovarian stimulation protocol, length of stimulation, number of retrieved oocytes, number of zygotes (two pronuclei) and insemination type were covariates and adjusted. After adjusting fully for all covariates, the cell number of day 3 embryos was significantly increased by 0.40 (95% CI 0.00, 0.79; P = 0.048) and 0.78 (95% CI 0.02, 1.54; P = 0.044) in the 15 µl/embryo and 10 µl/embryo group separately, compared with the 30 µl/embryo group. The proportions of implanted embryos were 42.1%, 48.7% and 0.0% in the 30 µl/embryo, 15 µl/embryo and 10 µl/embryo groups respectively. There was no statistical significance (P = 0.22) between the 30 µl/embryo group and the 15 µl/embryo group. After adjusting for confounders that were significant in univariate analysis, embryo density was still not associated with day 3 embryo implantation potential (P > 0.05). In a 30-µl microdrop, culturing embryos with an embryo density of both 15 and 10 µl/embryo increased the cell number of day 3 embryos, which did not benefit embryo implanting potential, compared with individual culture of 30 µl/embryo.

Embryo Density and Its Neutrality in Day-3 Embryo Development: A Retrospective Cohort Study.

Introduction: Many studies have shown that embryo density has an impact on day-3 embryo-developmental outcomes; however, embryo density remains controversial in clinical practice. We aimed to evaluate the association between embryo density and day-3 embryo-developmental outcomes in real world with the largest sample size. Methods: In 2018, we identified 10941 day-3 embryos from all female patients (n = 1568) in the study. The embryos were allocated to three embryonic densities: 30 µl/embryo (individual culture), 15 µl/embryo, and 10 µl/embryo (group culture). The primary outcomes were cleaving speed, quality, and proportion of successful implantations. The generalized estimate equation (GEE) model was used both in the univariate analysis and multivariable logistic regression analyses to investigate the relationship between embryo density and embryo-developmental outcomes. Results: There were 3064, 5695, and 2182 embryos in the 30 µl/embryo group, 15 µl/embryo group, and 10 µl/embryo group, respectively. The proportions of 7-10 cell embryos were 57.2%, 56.1%, and 58.3% in three densities with no statistical significance (P=0.37), respectively. The proportions of morphologically good embryos were 20%, 20.3%, and 20% in three densities with no statistical significance (P=0.85), respectively. Proportions of implanted embryos were 37.7%, 37.1%, and 27.8% with no statistical significance (P=0.36), respectively. After adjustment for confounders, which were significant in the univariate analysis, the embryo density was still not associated with day-3 embryo-cleaving speed, day-3 embryo quality, and day-3 embryo-implanting potential (all P > 0.05). Conclusion: In a 30 µl microdrop, the culturing embryos with embryo densities of 15, 10, and 30 µl/embryo (from zygotes to day 3) had similar developmental outcomes. The embryo density had no impact on day-3 embryo development.

Research progress of melatonin (MT) in improving ovarian function: a review of the current status.

Melatonin (MT) is an endogenous hormone mainly synthesized by pineal cells, which has strong endogenous effects of eliminating free radicals and resisting oxidative damages. Melatonin (MT) can not only regulate the body's seasonal and circadian rhythms; but also delay ovarian senescence, regulate ovarian biological rhythm, promote follicles formation, and improve oocyte quality and fertilization rate. This review aimd to provide evidence concerning the synthesis and distribution, ovarian function, and role of MT in development of follicles and oocytes. Moreover, the role of MT as antioxidative, participating in biological rhythm regulation, was also reviewed. Furthermore, the effects of MT on various ovarian related diseases were analyzed, particularly for the ovarian aging and polycystic ovary syndrome (PCOS).

LncRNAs induce oxidative stress and spermatogenesis by regulating endoplasmic reticulum genes and pathways.

Oligozoospermia or low sperm count is a leading cause of male infertility worldwide. Despite decades of work on non-coding RNAs (ncRNAs) as regulators of spermatogenesis, fertilization, and male fertility, the literature on the function of long non-coding RNAs (lncRNAs) in human oligozoospermia is scarce. We integrated lncRNA and mRNA sequencing data from 12 human normozoospermic and oligozoospermic samples and comprehensively analyzed the function of differentially expressed lncRNAs (DE lncRNAs) and mRNAs (DE mRNAs) in male infertility. The target genes of DE lncRNAs were identified using a Gaussian graphical model. Gene ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways were primarily enriched in protein transport and localization to the endoplasmic reticulum (ER). The lncRNA-mRNA co-expression network revealed cis- and trans-regulated target genes of lncRNAs. The transcriptome data implicated DE lncRNAs and DE mRNAs and their target genes in the accumulation of unfolded proteins in sperm ER, PERK-EIF2 pathway-induced ER stress, oxidative stress, and sperm cell apoptosis in individuals with oligozoospermia. These findings suggest that the identified lncRNAs and pathways could serve as effective therapeutic targets for male infertility.

The status and comparison of ovarian reserve between fertile and infertile healthy Chinese women of reproductive age.

ABSTRACT: We aimed to investigate ovarian reserve status, and explore differences in ovarian reserve between fertile and infertile healthy Chinese women of reproductive age.We recruited 442 fertile women aged 23 to 49 years (mean: 35.22 ±â€Š4.91 years) as subjects, and 196 infertile women aged 23 to 46 years (mean: 32.34 ±â€Š4.34 years) as controls. For all participants, a number of parameters were tested on days 2 to 4 of a spontaneous cycle, including basal serum follicle-stimulating hormone (FSH), estradiol (E2), luteinizing hormone (LH), total testosterone, anti-Müllerian hormone (AMH), ovarian response prediction index (ORPI), and antral follicle count (AFC).There were significant differences in terms of AFC, serum AMH levels, and ORPI among subject subgroups (10.58 ±â€Š5.80; 2.533 ±â€Š2.146 ng/mL; 1.28 ±â€Š1.87; respectively), and among control subgroups (12.44 ±â€Š5.69; 3.189 ±â€Š2.551 ng/mL; 1.88 ±â€Š2.68; respectively) (P < .01 for all). For both subjects and controls, AFC, AMH levels, and ORPI decreased gradually with increasing age, and presented with similar age-related trends; there were positive correlations between AMH and AFC (P < .001), and negative correlations between age and AFC, AMH, ORPI (P < .05 for all). There was a significant difference in age (P < .001), serum E2 (P < .01), and AMH (P < .01) levels between subjects and controls; however, when controlling for confounding factors (age, body mass index, total testosterone, and LH), we found no differences between the 2 groups with regards to the serum levels of AMH, FSH, E2, and AFC (P > .05 for all). Moreover, receiver operating characteristic curve analysis indicated that the significant variables of subjects and controls for evaluating ovarian reserve included age, AMH and ORPI, and ORPI was more valuable than other variables.A diminished ovarian reserve was one of the manifestations caused by female aging. When confounding factors were controlled for, we found no differences in ovarian reserve when compared between fertile and infertile women, and no correlation with infertility.

High anti-Müllerian hormone levels might not reflect the likelihood of clinical pregnancy rate in IVF/ICSI treatment.

OBJECTIVE: To investigate if high anti-Müllerian hormone (AMH) concentration is a useful tool to predict the outcome of assisted reproductive treatment. METHODS: Retrospective cohort study involving 520 patients who underwent IVF/ICSI procedures in a university hospital. We measured the serum AMH level on day 3 of the menstrual cycle. Based on AMH levels, we divided the patients into three groups as follows: low (<25th percentile) AMH group, average (25th to 75th percentile) AMH group and high (>75th percentile) AMH group. We recorded the fertilization rate (FR), the number of oocytes retrieved, the number of good quality embryos (GQEs) and the clinical pregnancy rate (CPR). RESULTS: There was no difference between the three AMH groups in terms of maternal age, body mass index (BMI), follicle-stimulating hormone (FSH), estradiol (E2), luteinizing hormone (LH) and testosterone (T) in the IVF/ICSI cycles. The women in the high serum AMH group had a higher number of retrieved oocytes than those in the low or average AMH groups (p < 0.01) in the IVF/ICSI cycles. Compared with the low or average AMH groups, the women with high AMH levels had a higher number of good quality embryos (GQEs) in the IVF/ICSI cycles (p < 0.01). However, high AMH women had no significantly higher clinical pregnancy rate (CPR) compared to the women in the low or average AMH groups. In addition, for the prediction of CPR, the AMH levels alone were not an independent predictor of CPR for IVF and ICSI cycles in the ROC curve analysis. CONCLUSIONS: High anti-Müllerian hormone levels are an independent predictor of the number of retrieved oocytes and good quality embryos (GQEs), but might not reflect the likelihood of higher clinical pregnancy rates (CPR) in IVF/ICSI treatment.

Melatonin induction of HSP90 expression exerts cryoprotective effect on ovarian tissue.

Our previous study revealed that melatonin (MLT) protected the quality of cryopreserved ovarian tissues in mice. This work was carried out to examine the role of MLT in inducing HSP90 expression of ovarian tissue for achieving cryoprotection. Pieces of ovarian tissues were obtained from 50 female rats treated with MLT at 0, 0.001, 0.01, 0.1, and 1 mM, respectively. After cryopreservation-thawing, HSP90 mRNA and protein level were evaluated using qRT-PCR and western blot. The qRT-PCR results revealed that HSP90 mRNA expression was significantly (p < 0.01) upregulated in MLT-treated groups in comparison with the controls (0 mM). Western blot revealed higher HSP90 protein expression in MLT-treated groups compared to control group (0 mM), thus further confirming that MLT positively affected HSP90 expression. Moreover, 0.1 mM MLT had better effects than other concentrations of MLT. Conclusively, findings in the present work provide a feasible technology for improving cryopreserved ovarian tissue quality through the addition of MLT to elicit HSP90 expression.

Antioxidative effect of melatonin on cryopreserved ovarian tissue in mice.

Cryopreservation of ovarian tissues (OTs) has become the most effective way to preserve the fertility of female cancer patients. However, cryopreservation of OTs is still relatively at an experimental stage. The aim of study is to examine the effect of melatonin (MTL) on cryopreserved-thawed OTs. Fragments of OTs were cryopreserved in medium containing different concentrations (0 mM, 0.001 mM, 0.01 mM, 0.1 mM and 1 mM) of MLT. The endogenous enzymes (GSH-PX, GSH, SOD, CAT and T-AOC), MDA and ROS levels were all evaluated after cryopreservation. Our results showed that the 0.1 mM of MLT significantly improved the survival and diameter of follicles (P < 0.001). Meanwhile, the antioxidant enzymes activities (including GSH-PX, GSH, SOD, CAT and T-AOC) were enhanced and MDA content were significantly decreased in 0.1 mM of MLT group compared to other groups (P < 0.001). Additionally, compared to the control group, MTL of 0.1 mM resulted in a significantly lower ROS level. In conclusion, MLT protects the quality of cryopreserved OTs by decreasing oxidative stress level and the optimal concentration is 0.1 mM.

Melatonin Inhibits Oxidative Stress and Apoptosis in Cryopreserved Ovarian Tissues via Nrf2/HO-1 Signaling Pathway.

In the field of assisted reproductive technology, female fertility preservation, particularly ovarian tissue cryopreservation in adolescent cancer patients, has attracted much attention. Melatonin (MLT) is well known for its antioxidative and anti-apoptotic properties; however, whether it can ameliorate the cryoinjury and inhibit the generation of reactive oxygen species (ROS) in cryopreserved ovarian tissues (OTs) has not yet been reported. Here, we demonstrated that MLT could protect follicular integrity; prevent cell apoptosis; decrease ROS, malondialdehyde (MDA), and nitric oxide (NO) levels; and increase activities of glutathione peroxidases (GSH-Px), glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD) in cryopreserved OTs. Furthermore, these effects may be related with the activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway, as evidenced by increased mRNA levels of Nrf2 downstream genes, including heme oxygenase-1 (HO-1), glutathione S-transferase M1 (GSTM1), SOD, and CAT. In summary, MLT can not only directly scavenge ROS but also significantly induce the activation of antioxidative enzymes via the Nrf2 signaling pathway, which is a new mechanism underlying the protection effects of MLT on cryopreserved OTs.

Protective effects of melatonin on male fertility preservation and reproductive system.

Melatonin is a ubiquitous indoleamine hormone synthesized primarily by the pineal gland. Diverse biological actions of melatonin involve quite complex mechanisms via its membrane receptors. More recently, studies have focused on the role of melatonin in male fertility preservation and male reproductive system. The protective effects of melatonin on immature testicular tissue freshness and activity maintenance and the preservation of sperm and spermatogonial stem cells (SSCs) have attracted considerable attention in recent years. Furthermore, since melatonin has strong antioxidant and anti-apoptotic properties, researchers have examined its potential role in male reproductive system. In this article, recent progress regarding melatonin's effects on male fertility preservation and its potential role is reviewed.

Melatonin Reduces Androgen Production and Upregulates Heme Oxygenase-1 Expression in Granulosa Cells from PCOS Patients with Hypoestrogenia and Hyperandrogenia.

BACKGROUND/AIMS: Polycystic ovary syndrome (PCOS) is an endocrine disorder characterized by abnormal hormone levels in peripheral blood and poor-quality oocytes. PCOS is a pathophysiological syndrome caused by chronic inflammation and oxidative stress. The aim of this study was to investigate the mechanism of melatonin regulation on androgen production and antioxidative damage in granulosa cells from PCOS patients with hypoestrogenia and hyperandrogenia. METHODS: Cumulus-oocyte complexes were collected from PCOS patients who had low levels of estrogen in follicular fluids. RESULTS: Melatonin triggered upregulation of cytochrome P450 family 19 subfamily A member 1 (CYP19A1) expression via the extracellular signal-regulated kinase pathway in luteinized granulosa cells. As a result, conversion of androgen to 17ß-estradiol was accelerated. We also found that melatonin significantly reduced the levels of inducible nitric oxide (NO) synthetase and NO in luteinized granulosa cells. Levels of transcripts encoding NF-E2-related factor-2 and its downstream target heme oxygenase-1 were also increased, leading to anti-inflammatory and antioxidant effects. We also found that melatonin could improve oocyte development potential. CONCLUSION: Our preliminary results showed that melatonin had a positive impact on oocyte quality in PCOS patients with hypoestrogenia and hyperandrogenia.

Effects of sperm proteins on fertilization in the female reproductive tract.

Mammalian fertilization that culminates by fusion of the male and female gametes is intricately regulated within the female reproductive tract. To become competent to fertilize an egg, the mammalian spermatozoa that enter the female reproductive tract must undergo a series of physiological changes, including hyperactivation, and capacitation. For reaching full competency, the acrosome, a specialized membrane-bound organelle that covers the anterior part of the sperm head, must undergo an acrosome reaction. For becoming competent to bind an ovum, and to penetrate the zona pellucida and cumulus, many sperm proteins are released in the course of the acrosome reaction. Ultimately, the acrosome binds to the oolemma and fusion of sperm and egg occurs. In this review, we outline current understanding of the roles and effects of some essential sperm proteins and their functions during fertilization in the female reproductive tract.