Induce Oocyte Maturation Research Articles

Polystyrene nanoplastic exposure actives ferroptosis by oxidative stress-induced lipid peroxidation in porcine oocytes during maturation

BackgroundPolystyrene nanoplastics (PS-NPs) are becoming increasingly prevalent in the environment with great advancements in plastic products, and their potential health hazard to animals has received much attention. Several studies have reported the toxicity of PS-NPs to various tissues and cells; however, there is a paucity of information about whether PS-NPs exposure can have toxic effects on mammalian oocytes, especially livestock. Herein, porcine oocytes were used as the model to investigate the potential effects of PS-NPs on mammalian oocytes.ResultsThe findings showed that different concentrations of PS-NPs (0, 25, 50 and 100 μg/mL) entering into porcine oocytes could induce mitochondrial stress, including a significant decrease in mitochondrial membrane potential (MMP), and the destruction of the balance of mitochondrial dynamic and micromorphology. Furthermore, there was a marked increase in reactive oxygen species (ROS), which led to oocyte lipid peroxidation (LPO). PS-NPs exposure induced abnormal intracellular iron overload, and subsequently increased the expression of transferrin receptor (TfRC), solute carrier family 7 member 11 (SLC7a11), and acyl-CoA synthetase long-chain family member 4 (ACSL4), which resulted in ferroptosis in oocytes. PS-NPs also induced oocyte maturation failure, cytoskeletal dysfunction and DNA damage. Cotreatment with 5 μmol/L ferrostatin-1 (Fer-1, an inhibitor of ferroptosis) alleviated the cellular toxicity associated with PS-NPs exposure during porcine oocyte maturation.ConclusionsIn conclusion, PS-NPs caused ferroptosis in porcine oocytes by increasing oxidative stress and altering lipid metabolism, leading to the failure of oocyte maturation.Graphical PS-NPs could enter oocytes, caused mitochondrial dysfunction and oxidative stress, induced lipid peroxidation and ferroptosis, which eventually resulted in failure of oocyte maturation.

Overcoming dysfunctional gametogenesis in hatchery-produced greater amberjack, Seriola dumerili using recombinant gonadotropins, and spawning induction using gonadotropin releasing hormone agonist-loaded implants

Female greater amberjack, Seriola dumerili reared in tanks have been inconsistent in entering or completing vitellogenesis. As a result, established spawning induction protocols employing gonadotropin-releasing hormone agonist (GnRHa) fail to induce oocyte maturation, ovulation and spawning. Males also exhibit reproductive dysfunctions resulting in low sperm production of relatively low quality. To ameliorate these problems, homologous Seriola dumerili single-chain recombinant Follicle stimulating hormone (sdrFsh) and Luteinizing hormone (sdrLh) were produced and administered to adult 4.8-year-old hatchery-produced (F1 generation) greater amberjack held in tanks, in order to enhance gametogenesis and increase reproductive performance (fecundity and fertilization success) upon spawning induction with GnRHa. Beginning at the onset of gametogenesis (27 April 2022), injections of sdrFsh and sdrLh were given for 6 consecutive weeks (a total of 7 treatments) in different combinations in males and females, and increasing doses. All fish treated with sdrFsh/Lh underwent complete gametogenesis, with females having oocytes in post-vitellogenesis and males producing releasable sperm at the time planned for the GnRHa spawning induction (6 June 2022). Furthermore, five of the six females initiated oocyte maturation prior to the GnRHa treatment, and at least one female also spawned spontaneously earlier (week 4). All but one untreated Control females did not complete vitellogenesis and exhibited follicular apoptosis/atresia, making them ineligible for GnRHa-induced spawning. Untreated Control males completed spermatogenesis and produced releasable sperm, but of somewhat lower spermatozoa density and significantly lower motility percentage and velocity compared to sdrFsh/Lh-treated males. GnRHa-induced spawning of the sdrFsh/Lh-treated fish enhanced mean daily relative fecundity and fertilization success, with embryo and larval survival >50%. These results are encouraging, and we expect that further optimization of dosage and administration timing can provide a reliable protocol for enhancing gametogenesis and promoting maturation in dysfunctional greater amberjack broodstocks maintained in aquaculture indoor facilities.

Resistant ovary syndrome: Two case reports and a literature review of effective controlled ovarian stimulation in IVF.

Resistant ovary syndrome (ROS) represents a rare reproductive endocrine disorder that is predominantly associated with infertility, characterized by heightened endogenous gonadotropin levels in the presence of a normal ovarian reserve. Patients with ROS typically exhibit a poor response to exogenous gonadotropins during controlled ovarian stimulation (COS). Due to the absence of a universally accepted effective COS protocol, this study aims to contribute to the existing body of literature by detailing 2 successful pregnancies achieved through conventional in vitro fertilization (c-IVF) in patients with ROS, and through retrospective analysis, seeks to elucidate the factors contributing to the successful ovarian stimulation in these cases, with the ultimate goal of establishing clinical guidelines for ROS management. The central challenge addressed in this study pertains to the effective induction of oocyte maturation during c-IVF COS in ROS patients. The study focuses on 2 infertile women diagnosed with ROS who sought to conceive via c-IVF. The patients were subjected to a COS protocol involving pituitary downregulation followed by ovarian stimulation using recombinant follicle-stimulating hormone (r-FSH) and human menopausal gonadotropin (HMG), preceded by 3 cycles of hormone replacement therapy (HRT) pretreatment. The proposed protocol elicited a favorable ovarian response, culminating in the retrieval of numerous mature oocytes and the development of multiple viable embryos via c-IVF, ultimately leading to successful live births post-embryo transfer. Our study suggests that the outlined COS protocol may serve as a viable treatment option for ROS patients aspiring to conceive through c-IVF, thereby potentially expanding the therapeutic repertoire for this challenging condition.

Recent insights into egg quality and larval vitality of the European eel Anguilla anguilla

To date, the eel industry still depends on wild-caught juveniles that are grown to marketable size. There is an urgent need to close the eel life cycle in captivity to make aquaculture independent of the natural population. With this artificial reproduction protocol, yolk-sac larvae can be produced but egg quality may be impaired. Low survival rates and high deformity rates are frequently observed during the first week after hatching. Over the past four years, we have conducted studies with the aim to optimize the artificial reproduction protocol, thereby focussing on increasing egg and larval quality. Weekly carp or salmon pituitary extract (PE) treatment was successfully replaced with recombinant gonadotropins (rGTHs) to mature female eels and produce larvae. 17α,20β-dihydroxy-4-pregnen-3-one (DHP) was replaced with upstream precursor progesterone (P) to induce the endogenous production of DHP by the female eel. DHP and P were found equally potent in inducing oocyte maturation and ovulation. The effects of antibiotics on larval survival and the occurrence of deformities were investigated. Antibiotic treatment increased survival and decreased the occurrence of deformities indicating bacterial infection as an important cause. A deformity determination key for young eel larvae has been developed that provides a framework of reference for larval deformities which will be instrumental with gaining insights on the reasons behind each larval deformity. These improvements of the artificial reproduction protocol and hatchery practices will contribute to the production of robust eel larvae that survive, grow and metamorphose into juveniles that will later be able to reproduce in captivity.

Melatonin and its Emerging Physiological Role in Reproduction: A Review and Update.

Melatonin is a neuroendocrine hormone secreted by the pineal gland. The secretion of melatonin follows a circadian rhythm controlled by the suprachiasmatic nucleus, and its secretion is synchronized with the changes in light and dark periods in nature, with the highest secretion level at night. Melatonin is a critical hormone that coordinates external light stimulation and cellular responses of the body. It transmits information about the environmental light cycle, including the circadian and seasonal rhythms, to the relevant tissues and organs in the body, which, along with changes in its secretion level, ensures that its regulated functional activities are adapted in response to changes in the outside environment. Melatonin takes beneficial actions mainly through the interaction with specific membrane-bound receptors, termed MT1 and MT2. Melatonin also acts as a scavenger of free radicals via non-receptor-mediated mechanism. For more than half of acentury melatonin has been associated with vertebrate reproduction, especially in the context of seasonal breeding. Though modern humans show little remaining reproductive seasonality, the relationships between melatonin and human reproduction continue to attract extensive attention. Melatonin plays important roles in improving mitochondrial function, reducing the damage of free radicals, inducing oocyte maturation, increasing fertilization rate and promoting embryonic development, which improves the outcomes of in vitro fertilization and embryo transfer. The present article reviews the progress that has been made in our evolving understanding of the physiological role of melatonin in reproduction and its potential clinical applications in reproductive medicine.

GnRH agonist trigger in poor prognosis patients undergoing a multicycle approach through DuoStim or consecutive stimulations: a SWOT analysis.

Identify the most recent and significant evidence regarding the ovulation trigger within the framework of a multicycle approach through DuoStim, providing valuable insights for improving treatment strategies in patients with a poor prognosis. The trigger method plays a pivotal role in optimizing in-vitro fertilization (IVF) stimulation, influencing oocyte retrieval and maturation rates, as well as follicle recruitment in consecutive ovarian stimulations such as double stimulation. Decision-making involves multiple factors and, while guidelines exist for conventional stimulation, specific recommendations for the multicycle approach are not well established. The different methods for inducing oocyte maturation underscore the need for personalization of IVF protocols. The GnRH agonist trigger induces rapid luteolysis and establishes favorable hormonal conditions that do not adversely affect the recruitment of consecutive follicular waves in the context of DuoStim. It serves as a valid alternative to hCG in freeze-all cycles. This strategy might enhance the safety and flexibility of ovarian stimulations with no impact on oocyte competence and IVF efficacy.

Evidence of binding between diethylstilbestrol (DES) and the goldfish (Carassius auratus) membrane progesterone receptor α

Background In a previous study, diethylstilbestrol (DES) was shown to induce oocyte maturation in fish. In the present study, the interaction of DES on goldfish membrane progesterone receptor α (GmPRα) was investigated using a competitive binding assay with radiolabeled steroids. The results indicate that DES exerts its effects on membrane progesterone receptor alpha (mPRα) and induces oocyte maturation through nongenomic steroid mechanisms. This study provides empirical data that demonstrate the binding between DES and GmPRα. Methods Binding of DES to GmPRα was achieved by using radiolabeled DES and recombinant GmPRα expressed in culture cells or purified GmPRα proteins that coupled to graphene quantum dots (GQDs). Additionally, the competitive binding of fluorescently labeled progesterone to GmPRα-expressing cells was evaluated. Results Although significant nonspecific binding of radiolabeled DES to the cell membrane that expresses GmPRα has been observed, specific binding of DES to GmPRα has been successfully identified in the presence of digitonin. Furthermore, the specific binding of DES to GmPRα was confirmed by a binding assay using GQD-GmPRα. The radiolabeled DES was shown to bind to GQD-GmPRα. Additionally, the competition for the binding of fluorescently labeled progesterone to GmPRα-expressing cells was achieved with the DES. Conclusions The results of the experiments revealed that DES binds to GmPRα. Thus, it can be concluded that DES induces goldfish oocyte maturation by binding to GmPRα.

In vivo induction of male sexual behavior in zebrafish by adding agents to water.

Successful fertilization in fish mating occurs when egg maturation in the ovary of the female, ovulation, sperm maturation in the testis of the male, and reproductive behaviors in both sexes are triggered in synchrony. The male sexual behavior of fish is induced by hormones and pheromones. In a previous study, we demonstrated that externally applied hormones added to the water can induce oocyte maturation and ovulation in female zebrafish. Here, we attempted to establish a similar method to induce the sexual behavior of male zebrafish. The male sex steroid testosterone (Tes) triggered sexual behavior within several hours in vivo when administered directly into the surrounding water. A selective agonist for membrane progesterone receptor (mPR), Org OD-02 (Org), also induced sexual behavior. Through trials of various combinations of compounds, we found that the most effective conditions were achieved by treatment with a mixture of testosterone (Tes) and Org. The effect of treatment was evaluated by the number of fertilized eggs obtained by pairing with females with induced ovulation in vivo. The period necessary for the induction of male sexual behavior was evaluated by time course experiments. The success rate of mating and the number of fertilized eggs reached the maximum level at 3-4 hours of treatment. The duration of hormonal treatment was confirmed by counting the number of hooking occurrences, which is the final cue to induce spawning by females. In summary, we have established a method to induce male sexual behavior in zebrafish in vivo. The method can be used to obtain fertilized eggs in zebrafish by simply adding agents into the water.

Neurotensin induces sustainable activation of the ErbB-ERK1/2 pathway, which is required for developmental competence of oocytes in mice.

LH induces the expression of EGF-like factors and their shedding enzyme (ADAM17) in granulosa cells (GCs), which is essential for ovulation via activation of the ErbB-ERK1/2 pathway in cumulus cells (CCs). Neurotensin (NTS) is reported as a novel regulator of ovulation, whereas the NTS-induced maturation mechanism in oocytes remains unclear. In this study, we focused on the role of NTS in the expression of EGF-like factors and ErbBs, and ADAM17 activity, during oocyte maturation and ovulation in mice. The expression and localization in GC and CC were examined. Next, hCG and NTS receptor 1 antagonist (SR) were injected into eCG-primed mice, and the effects of SR on ERK1/2 phosphorylation were investigated. Finally, we explored the effects of SR on the expression of EGF-like factors and ErbBs, and ADAM17 activity in GC and CC. NTS was significantly upregulated in GC and CC following hCG injection. SR injection suppressed oocyte maturation and ERK1/2 phosphorylation. SR also downregulated part of the expression of EGF-like factors and their receptors, and ADAM17 activity. NTS induces oocyte maturation through the sustainable activation of the ERK1/2 signaling pathway by upregulating part of the EGF-like factor-induced pathway during oocyte maturation in mice.

#285 : Amphiregulin Increases Pentraxin 3 Production via the EGFR-Mediated Erk1/2 Signaling in Human Granulosa Cells

Background and Aims: Pentraxin 3 (PTX3) plays a key role in the assembly of the extracellular matrix, which is critical for cumulus expansion, ovulation, and in vivo fertilization. As a member of the epidermal growth factor family, amphiregulin (AREG) mediates luteinizing hormone (LH)-induced oocyte maturation and cumulus expansion in mammalian follicles. The aim of this study was to investigate whether AREG regulates the expression and production of PTX3 in human granulosa cells and to examine its underlying molecular determinants. Method: Immortalized human granulosa cells (SVOG cells) and primary human granulosa-lutein (hGL) cells obtained from women undergoing in vitro fertilization in an academic research center were used as the study models. The expression and accumulated levels of PTX3 were examined following cell incubation with AREG at different time points using the RT-qPCR and ELISA, respectively. Two kinase inhibitors (AG1478, and U0126) and small interfering RNAs targeting EGF receptor (EGFR) were used to verify the specificity of the effects and to investigate the molecular mechanisms. The results were analyzed by one-way analysis of variance. Results: The results showed that AREG upregulated the expression and production of PTX3 in primary and immortalized hGL cells. Additionally, using a dual inhibition approach (kinase inhibitors and siRNA-based expression knockdown), we demonstrated that this effect was mainly mediated by the EGFR receptor. Furthermore, we revealed that the Erk1/2 signaling is the downstream signaling pathway that mediates the increase in PTX expression and production in response to AREG treatment in hGL cells. Conclusion: AREG upregulated the expression of PTX3, leading to increased production of PTX3 in hGL cells. The AREG-induced cellular activities were most likely driven by the EGFR-mediated Erk1/2-dependent signaling pathway. Our findings shed light on the detailed molecular mechanisms by which AREG regulates the process of cumulus expansion and subsequent ovulation in humans.

Novel variants in TUBB8 gene cause multiple phenotypic abnormalities in human oocytes and early embryos

BackgroundThe genotype-phenotype relationships between TUBB8 variants and female infertility are difficult to clearly define due to the complex inheritance patterns and the highly heterogeneous phenotypes. This study aims to identify novel TUBB8 variants and relevant phenotypes in more infertile females.MethodsA total of 35 females with primary infertility were recruited from two reproductive centers and investigated for identifying variants in TUBB8. Pedigree analysis, in-silico analysis and molecular remodeling were performed to assess their clinical significance. The effects of the variants on human oocytes and embryos as well as HeLa cells were analyzed by morphological observations, immunostaining and Western blot.ResultsWe totally identified five novel variants (p.G13R, p.Y50C, p.T136I, p.F265V and p.T366A) and five previously reported variants (p.I4L, p.L42V, p.Q134*, p.V255M and p.V349I) in TUBB8 from 9 unrelated females with primary infertility. These variants were rare and highly conserved among different species, and were inherited in autosomal dominant/recessive patterns, or occurred de novo. In vitro functional assays in HeLa cells revealed that exogenous expression of mutant TUBB8 proteins caused different degrees of microtubule structural disruption. The existence of these pathogenic TUBB8 variants finally induced oocyte maturation arrest or morphological abnormalities, fertilization failure, cleavage failure, embryonic development defects and implantation failure in the affected females.ConclusionThese findings enriched the variant spectrum of TUBB8 gene and could contribute to optimize genetic counselling and clinical management of females with primary infertility.

Endocrine profile of the kisspeptin receptor agonist MVT-602 in healthy premenopausal women with and without ovarian stimulation: results from 2 randomized, placebo-controlled clinical tricals

Kisspeptin is an essential regulator of hypothalamic gonadotropin-releasing hormone release and is required for physiological ovulation. Native kisspeptin-54 (KP54) can induce oocyte maturation during in vitro fertilization treatment, including in women at high risk of ovarian hyperstimulation syndrome. MVT-602 is a potent kisspeptin receptor agonist with prospective utility to treat anovulatory disorders by triggering oocyte maturation and ovulation during medically assisted reproduction (MAR). Currently, the endocrine profile of MVT-602 during ovarian stimulation is unreported. ObjectiveTo determine the endocrine profile of MVT-602 in the follicular phase of healthy premenopausal women (Phase-1 trial), and after minimal ovarian stimulation to more closely reflect the endocrine milieu encountered during MAR (Phase-2a trial). DesignTwo randomized, placebo-controlled, parallel group, dose-finding trials. SettingClinical trials unit, Netherlands. ParticipantsHealthy women aged 18-35 years, either without (Phase-1; n=24), or with ovarian stimulation (Phase-2a; n=75). InterventionsPhase-1: Single subcutaneous dose of MVT-602 (0.3, 1.0, or 3.0 μg) or placebo, (n=6 per dose).Phase-2a: Single subcutaneous dose of MVT-602 (0.1, 0.3, 1.0, or 3.0 μg; n=16-17 per dose), triptorelin 0.2 mg (n=5; active comparator), or placebo (n=5). Main Objectives and Outcome MeasuresPhase-1: Safety/tolerability; pharmacokinetics; pharmacodynamics (LH and other reproductive hormones).Phase-2a: Safety/tolerability; pharmacokinetics; pharmacodynamics (LH and other reproductive hormones); time to ovulation assessed by transvaginal ultrasound. ResultsIn both trials, MVT-602 was safe and well-tolerated across the entire dose-range. It was rapidly absorbed and eliminated, with a mean elimination half-life of 1.3-2.2 hours.In the Phase-2a trial, LH concentrations increased dose-dependently; mean maximum change from baseline of 82.4 IU/L at 24.8 hours was observed after administration of 3μg MVT-602 and remained above 15 IU/L for 33 hours. Time to ovulation following drug administration was 3.3-3.9 days (MVT-602), 3.4 days (triptorelin), and 5.5 days (placebo). Ovulation occurred within 5 days of administration in 100% (3 μg), 88% (1μg), 82% (0.3μg), and 75% (0.1μg), of women after MVT-602, 100% after triptorelin, and 60% after placebo. ConclusionsMVT-602 induces LH concentrations of similar amplitude and duration as the physiological mid-cycle LH surge with potential utility for induction of oocyte maturation and ovulation during MAR. Trial RegistrationsEUDRA-CT: 2017-003812-38, 2018-001379-20

Production of marmoset eggs and embryos from xenotransplanted ovary tissues

The common marmoset (Callithrix jacchus) has attracted attention as a valuable primate model for the analysis of human diseases. Despite the potential for primate genetic modification, however, its widespread lab usage has been limited due to the requirement for a large number of eggs. To make up for traditional oocyte retrieval methods such as hormone administration and surgical techniques, we carried out an alternative approach by utilizing ovarian tissue from deceased marmosets that had been disposed of. This ovarian tissue contains oocytes and can be used as a valuable source of follicles and oocytes. In this approach, the ovarian tissue sections were transplanted under the renal capsules of immunodeficient mice first. Subsequent steps consist of development of follicles by hormone administrations, induction of oocyte maturation and fertilization, and culture of the embryo. This method was first established with rat ovaries, then applied to marmoset ovaries, ultimately resulting in the successful acquisition of the late-stage marmoset embryos. This approach has the potential to contribute to advancements in genetic modification research and disease modeling through the use of primate models, promoting biotechnology with non-human primates and the 3Rs principle in animal experimentation.

The induction of oocyte maturation and ovulation in the European eel (Anguilla anguilla): in vitro and in vivo comparison of progesterone with 17α,20β-dihydroxy-4-pregnen-3-one.

Ovulation in European eel is induced by injection of 17α,20β-dihydroxy-4-pregnen-3-one (DHP) as the maturation-inducing hormone (MIH). Female eels need to ovulate within 18h after injection to release good quality eggs. Progesterone (P), as an upstream precursor of DHP, may promote endogenous DHP production and improve egg quality. The purpose of this study was therefore to compare treatment of P with DHP on batch level, in vitro, to determine dose-response effects, and in vivo, at a single dose. For the in vitro experiment, ovarian tissue was extracted and placed in culture plates containing hormone-free medium and media supplemented with the treatment: DHP at 1, 10 and 100ngmL-1, or P at 10, 100 and 1,000ngmL-1. At the start of incubation, the folliculated oocytes were sampled for histology, microscopy and qPCR. After incubation for 12 and 18h, the oocytes were sampled for microscopy and qPCR analysis. For the in vivo experiment, females were either injected with DHP or P at a dose of 2mgkg-1 to assess their effects on ovulation and reproductive success. At the moment of release, eggs were sampled for RNA sequencing to compare effects of DHP and P on the expression of genes involved in egg quality aspects. Remaining eggs were fertilized and larval viability was recorded. Both DHP and P were able to induce GVBD (DHP at 10 and 100ngmL-1, P at 100 and 1,000ngmL-1) in vitro. Expression of genes involved in oocyte maturation and ovulation was similar in vitro for both DHP and P treatments. Regarding the in vivo results, RNAseq results reflected similar DHP and P effects on the expression of genes involved in egg quality aspects. Females injected with either DHP or P ovulated, released eggs, and were equally able to produce larvae without any differences in reproductive success. Our results support the conclusion that DHP and P work equally well in vitro and in vivo. P is more attractive to apply as the price is 3,000 times lower than the price of DHP.

Betacellulin regulates gap junction intercellular communication by inducing the phosphorylation of connexin 43 in human granulosa-lutein cells

BackgroundThe gap junction protein, connexin 43 (Cx43) is highly expressed in human granulosa-lutein (hGL) cells. The phosphorylation of certain amino acid residues in the Cx43 protein has been shown to be related to a decline in gap junction intercellular communication (GJIC), which subsequently affects oocyte meiotic resumption. As a member of the epidermal growth factor (EGF) family, betacellulin (BTC) mediates luteinizing hormone (LH)-induced oocyte maturation and cumulus cell expansion in mammalian follicles. Whether BTC can regulate Cx43 phosphorylation, which further reduces Cx43-coupled GJIC activity in hGL cells remains to be determined.MethodsImmortalized human granulosa cells (SVOG cells) and primary human granulosa-lutein cells obtained from women undergoing in vitro fertilization in an academic research center were used as the study models. The expression levels of Cx43 and phosphorylated Cx43 were examined following cell incubation with BTC at different time points. Several kinase inhibitors (sotrastaurin, AG1478, and U0126) and small interfering RNAs targeting EGF receptor (EGFR) and receptor tyrosine-protein kinase 4 (ErbB4) were used to verify the specificity of the effects and to investigate the molecular mechanisms. Real-time-quantitative PCR and western blot analysis were used to detect the specific mRNA and protein levels, respectively. GJIC between SVOG cells were evaluated using a scrape loading and dye transfer assay. Results were analyzed by one-way analysis of variance.ResultsThe results showed that BTC induced the rapid phosphorylation of Cx43 at serine368 without altering the expression of Cx43 in primary and immortalized hGL cells. Additionally, using a dual inhibition approach (kinase inhibitors and siRNA-based expression knockdown), we demonstrated that this effect was mainly mediated by the EGFR but not the ErbB4 receptor. Furthermore, using a protein kinase C (PKC) kinase assay and a scrape-loading and dye transfer assay, we revealed that PKC signaling is the downstream signaling pathway that mediates the increase in Cx43 phosphorylation and subsequent decrease in GJIC activity in response to BTC treatment in hGL cells.ConclusionsBTC promptly induced the phosphorylation of connexin 43 at Ser368, leading to decreased GJIC activity in hGL cells. The BTC-induced cellular activities were most likely driven by the EGFR-mediated PKC-dependent signaling pathway. Our findings shed light on the detailed molecular mechanisms by which BTC regulates the process of oocyte meiotic resumption.

Relaxin-like Gonad-Stimulating Peptides in Asteroidea.

Starfish relaxin-like gonad-stimulating peptide (RGP) is the first identified peptide hormone with gonadotropin-like activity in invertebrates. RGP is a heterodimeric peptide, comprising A and B chains with disulfide cross-linkages. Although RGP had been named a gonad-stimulating substance (GSS), the purified peptide is a member of relaxin-type peptide family. Thus, GSS was renamed as RGP. The cDNA of RGP encodes not only the A and B chains, but also signal and C-peptides. After the rgp gene is translated as a precursor, mature RGP is produced by eliminating the signal and C-peptides. Hitherto, twenty-four RGP orthologs have been identified or predicted from starfish in the orders Valvatida, Forcipulatida, Paxillosida, Spinulosida, and Velatida. The molecular evolution of the RGP family is in good accordance with the phylogenetic taxonomy in Asteroidea. Recently, another relaxin-like peptide with gonadotropin-like activity, RLP2, was found in starfish. RGP is mainly present in the radial nerve cords and circumoral nerve rings, but also in the arm tips, the gonoducts, and the coelomocytes. RGP acts on ovarian follicle cells and testicular interstitial cells to induce the production of 1-methyladenine (1-MeAde), a starfish maturation-inducing hormone. RGP-induced 1-MeAde production is accompanied by an increase in intracellular cyclic AMP levels. This suggests that the receptor for RGP (RGPR) is a G protein-coupled receptor (GPCR). Two types of GPCRs, RGPR1 and RGPR2, have been postulated as candidates. Furthermore, 1-MeAde produced by RGP not only induces oocyte maturation, but also induces gamete shedding, possibly by stimulating the secretion of acetylcholine in the ovaries and testes. Thus, RGP plays an important role in starfish reproduction, but its secretion mechanism is still unknown. It has also been revealed that RGP is found in the peripheral adhesive papillae of the brachiolaria arms. However, gonads are not developed in the larvae before metamorphosis. It may be possible to discover new physiological functions of RGP other than gonadotropin-like activity.

Pre-culture with transferrin-Fe3+ before in vitro maturation improves the developmental competence of porcine oocytes matured in vitro.

Since the developmental competence of oocytes cultured after in vitro maturation (IVM) is low, it is necessary to improve the IVM method for efficient offspring production. In this study, we revealed that transferrin (TF)-Fe3+ was accumulated in follicular fluid with increasing the follicular diameter, and that TF receptor (TFR1) was localized in granulosa cells of pig. Thus, we hypothesized that TF-Fe3+ would be a factor in the induction of developmental competence of porcine oocytes. To mimic the follicular development environment, cumulus-oocyte complexes (COCs) were cultured in pre-IVM medium (low dose of FSH) without or with Holo-TF (monoferric or diferric TF) or Apo-TF (non-iron bond TF). After pre-IVM without or with Holo-TF, COCs were cultured in IVM medium (high dose of FSH and EGF) without or with Holo-TF. Cultivation with Holo-TF increased the expression of follicular development maker (Cyp19a1 and Ccnd2), E2 production, and proliferative activity of cumulus cells, whereas cultivation with Apo-TF did not show these positive effects. The treatment with Holo-TF during pre-IVM, but not during IVM, dramatically induced oocyte maturation with increasing the blastocyst rate. We succeeded in showing for the first time that the cultivation with Holo-TF in pre-IVM can produce embryos in pig with high efficiency.

Using GnRH agonists in combination with hCG in antagonist ART cycles: A SCOPING Review of recent evidences.

Assisted Reproductive technology encompasses all techniques involving ovarian stimulation to produce high-quality oocytes and manipulation of both oocytes and sperm in vitro to produce embryos for the purpose of reproduction. The final maturation of oocytes induced by a "trigger" is a crucial step with the potential to affect in vitro fertilization outcomes. Human chorionic gonadotropin has traditionally been used as a substitute for luteinizing hormone to induce final oocyte maturation and meiosis. However, this practice may cause a potentially fatal iatrogenic complication known as ovarian hyperstimulation syndrome, which can cause significant morbidity and, in rare cases, death in otherwise healthy women. Thus, gonadotropin releasing hormone agonists have been promoted as a safer alternative for inducing oocyte maturation, albeit at the expense of luteal phase defect. Since then, various combinations of gonadotropin releasing hormone agonists and human chorionic gonadotropin have been tried. This scoping review evaluates these trigger combinations in various types of responders.

To investigate the role of rutin on bisphenol-A induced female infertility in rats.

The aim of this study is to see how rutin affects female infertility in rats after exposure to bisphenol-A (BA). Now a day, infertility is a major issue in the health care system. Currently, various chemicals and toxins are exposed to our biological system. Moreover, globally the improvement in reproductive health is alarming in developing and developed countries. The complete understanding and full therapeutic spectrum of natural medicines like citrus fruit-derived phytoconstituent i.e., rutin is not explored yet. However, rutin is contributed to the improvement of vascular health and smooth muscle tissue functions. The proposed research work is designed to explore the role of rutin on bisphenol-A (BA) induced female infertility in rats. BA is a potent endocrine disruptor and it causes female infertility in the rat. The inducer of oocyte maturation with nitric oxide donor i.e., sodium nitroprusside (SNP) was used for female infertility in the rat. The test compound rutin was administered with variable doses for 60 minutes per day for 21 days for this study. The female infertility of rats was assessed by male-female interaction behaviours, and anxiety behaviours were tested on 0, 7, 14, and 21st days. The biomarkers levels i.e., estradiol-17b (E2), follicle-stimulating hormone (FSH) and antimullerian tubulin hormone (AMH), reduced glutathione (GSH), and lipid peroxidation (MDA) levels were estimated at the end of the experimental protocol. The treatment of rutin is ameliorated the BA-associated female reproductive behaviours and biomarkers level. Hence, it may be useful to improve female reproductive health due to its potential multi-targeted actions like hormonal regulation, anti-oxidant, and anti-peroxidative actions.

The Science of IVM

Oocyte in vitro maturation (IVM) makes use of oocytes from patients that have received minimal or no gonadotrophin stimulation. Whilst this brings many advantages to patients, this typically means oocytes are collected from small-medium sized (4-12 mm) antral follicles. These oocytes are under-developed, and yet removal of these from the follicle and culture in vitro leads to spontaneous oocyte meiotic maturation, without the benefit of the physiological signals that naturally induce oocyte maturation at ovulation. Using animals models, over the past decade seminal advances have been made in our understanding of the fundamental mechanisms regulating oocyte maturation in vivo. Most IVM systems, as practised clinically today, typically do not recapitulate these key cellular processes, possibly accounting for the lower efficiency of IVM compared to IVF. A key objective of modern approaches to IVM is to restore in vitro, as far as possible, the natural processes that occur during oocyte maturation in vivo. One strategy to achieve this in IVM is to: 1) prevent spontaneous meiotic resumption at oocyte collection using phosphodiesterase inhibitors, then 2) artificially maintain or elevate cumulus-oocyte complex (COC) cAMP levels, and finally to 3) induce oocyte meiotic resumption using EGF-like peptides. This typically requires the use of biphasic or 2-step IVM systems. One such biphasic IVM system is called capacitation-IVM (CAPA-IVM), as the oocyte is “capacitated” for development in vitro. CAPA-IVM uses the follicle’s natural oocyte meiotic inhibitor, c-type natriuretic peptide (CNP), in the pre-IVM phase, and amphiregulin as the oocyte meiotic inducer in the second IVM phase. Such biphasic-IVM systems typically lead to subsequent improvements in embryo yield compared to standard IVM, and indeed this is the case for CAPA-IVM. Several pilot RCTs and a large RCT of CAPA-IVM vs conventional IVF have been completed, and CAPA-IVM is now practiced in a few centres globally and is commencing in Sydney. The development and clinical application of modern IVM systems, built on decades of animal scientific research, is a bench-to-bedside success story of biomedical research. IVM is now a viable minimally invasive procedure for the treatment of infertility and for fertility preservation in female cancer patients.