Profile of melatonin and its receptors and synthesizing enzymes in cumulus-oocyte complexes of the developing sheep antral follicle-a potential estradiol-mediated mechanism

From spermatogenesis to fertilisation: the role of melatonin on ram spermatozoa

This review presents recent findings on the effect of melatonin on ram spermatozoa. This hormone regulates seasonal reproduction in the ovine species through the hypothalamic-pituitary-gonadal axis, but it also exerts direct effects on spermatogenesis, seminal quality and fertility. In the testis, melatonin stimulates blood flow to this organ, but it also appears to be involved in the differentiation of spermatogonial stem cells and the secretion of testosterone through the MT1 and MT2 receptors. In the epididymis, this hormone modulates sperm maturation and the secretory activity of epidydimal epithelial cells. In addition, the antioxidant activity of melatonin may protect spermatozoa from oxidative damage during their formation in the testis and their maturation in the epididymis. After ejaculation, the melatonin present in seminal plasma may also protect sperm from oxidative damage and premature capacitation and may improve seminal quality. Finally, once the sperm begins its transit through the female genital tract, melatonin may modulate sperm capacitation. Thus, melatonin could have a bimodal activity in ram sperm capacitation, so high concentrations, such as those in seminal plasma, have a decapacitating effect. In contrast, low concentrations, such as those present in the female reproductive tract, may promote it, likely through interaction with MT2 receptors. In addition, melatonin could also be involved in chemotaxis and fertilisation, although further studies are needed to elucidate the specific role of melatonin in these processes. Finally, the effect of latitude and melatonin receptor gene polymorphisms in ram reproduction is also discussed.

SHR0302 Improves Treg/Th17 Imbalance in Patients with Systemic Lupus Erythematosus

IL-6-mediated JAK1/STAT3 signaling pathway is involved in the development of Th17 cells, which play an essential role in the pathogenesis of various autoimmune diseases such as systemic lupus erythematosus (SLE). To evaluation of the regulatory and anti-inflammatory effects of the JAK1/STAT3 inhibition in SLE, we evaluated the effects of SHR0302 on regulatory T cell (Treg)/Th17 balance. Thirty-two patients with SLE and twenty-nine healthy subjects were enrolled in this study. The mRNA expression levels of anti- and pro-inflammatory cytokines, such as FOXP3, ROR-γt, IL-10, IL-17A, IL-21, and IRF-4, were determined using real-time PCR, and the cytokine levels of IL-6, IL-10, IL-17A, TNF-α, and IFN-γ were analyzed by ELISA. The frequency and in vitro development of CD4+ CD25+ Foxp3+ Treg and Th17 cells were evaluated by flow cytometry. SHR0302 could increase the mRNA expression and cytokine level of Treg-related molecules. Furthermore, numbers of Treg cells were increased, after treatment with SHR0302. In contrast, the mRNA expression level of Th17-related molecules, ROR-γt, IL-17A, and IL-21, were decreased. Reduction of inflammatory cytokine levels was a confirmation of the modulating effect of the SHR0302, including IL-6, IL-17, TNF-α, and IFN-γ. In addition, frequency of Th17 cells were reduced by SHR0302. Our study shows that SHR0302 regulating the JAK1/STAT3 pathway can be a new treatment option for SLE.

Uterus histomorphometry of alpacas (Vicugna pacos) in induced luteal phase, with GnRH or copulation

Background

Alpacas have reproductive traits such as induced ovulation and a higher gestation rate in the left uterine horn (LUH). Additionally, low fertility and high embryonic mortality are significant challenges in alpaca breeding. To address these issues, it is essential to study the histological changes occurring in the uterine wall during day 8 of the luteal phase (LP).

Aim

This research aims to describe these changes in alpacas with induced ovulation using GnRH or copulation.

Methods

The study was conducted on 8 sexually mature fertile alpacas with a preovulatory follicle of ≥ 7 mm. Ovulation was induced with GnRH (G1, n = 3) and natural mating' (G2, n = 5), confirmed by ultrasound showing the disappearance of the follicle and formation of the corpus luteum (CL). On day 8 of the LP, samples of the uterine wall from the right and LUHs were obtained through a midline laparotomy. A uterine lavage with PBS was also performed, and no embryo-ova was found. The tissues were fixed, processed, and stained with Hematoxylin and Eosin. Measurements of the myometrium and endometrium, the area of the superficial and deep endometrial glands, the height of the gland cells, and the height of the endometrial mucosal cells were performed using microscopy and software. The measurements were taken in microns (um), from 12 different photographs per animal.

Results

In G2 (copulation), greater thickness of the endometrium and myometrium, as well as a larger area of the superficial glands and cell height, were observed (p < 0.005). Additionally, the area of the superficial glands in the left horn was greater compared to the right.

Conclusion

The thickness of the myometrium and endometrium, and the area of the superficial glands of the LUH in alpacas during the LP (day 8), induced by copulation (G2), show better development. This research provides new insights into changes in the histomorphometry of the alpacas' uterus during this stage and is the first report on this species.

Melatonin regulates the antioxidant capacity of sheep granulosa cells through a novel uORF-Nrf2aa mediated Nrf2/KEAP1 pathway

Ovarian dysfunction stands as a prevalent contributor to female infertility, with its etiology intertwined with genetic, autoimmune, and environmental factors. Within the ovarian follicles, granulosa cells (GCs) represent the predominant cell population. Alterations in GCs, notably oxidative stress (OS) and the consequential surge in reactive oxygen species (ROS), play pivotal roles in the orchestration of ovarian function. Nrf2aa, a newly identified upstream open reading frame (uORF), is situated within the 5' untranslated region (5'UTR) of sheep Nrf2 mRNA and is regulated by melatonin, a crucial intrafollicular antioxidant. In this study, we have noted that Nrf2aa has the capacity to encode a peptide and exerts a negative regulatory effect on the translation efficiency (TE) of the Nrf2 CDs region. Further in vitro experiments, we observed that interfering with Nrf2aa can enhance the cellular functionality of GCs under 3-np-induced oxidative stress, while overexpressing Nrf2aa has the opposite effect. Furthermore, overexpression of Nrf2aa counteracts the rescuing effect of melatonin on the cellular functions of GCs under oxidative stress conditions, including estrogen secretion, proliferation, apoptosis, and many more. Finally, we confirmed that Nrf2aa, by regulating the expression of key proteins in the Nrf2/KEAP1 signaling pathway, further modulates the antioxidant levels in GCs.

Ovarian overexpression of ASMT gene increases follicle numbers in transgenic sheep: Association with lipid metabolism

Melatonin plays an important role in mammalian reproductive activities, to further understand the effects of endogenous melatonin on functions of ovary, the transgenic sheep with overexpression of melatonin synthetic enzyme gene ASMT in ovary were generated. The results showed that total melatonin content in follicular fluid of transgenic sheep was significantly greater than that in the wild type. Accordingly, the follicle numbers of transgenic sheep were also significantly greater than those in the WT. The results of follicular fluid metabolites sequencing showed that compared with WT, the differential metabolites of the transgenic sheep were significantly enriched in several signaling pathways, the largest number of metabolites was lipid metabolism pathway and the main differential metabolites were lipids and lipoid molecules. SMART-seq2 were used to analyze the oocytes and granulosa cells of transgenic sheep and WT sheep. The main differential enrichment pathway was metabolic pathway, in which lipid metabolism genes accounted for the majority. In conclusion, this is the first report to show that ovary overexpression of ASMT increased local melatonin production and follicle numbers. These results may imply that ASMT plays an important role in follicle development and formation, and melatonin intervention may be a potential method to promote this process.

[Effect of Intrauterine Perfusion of Granulocyte Colony-Stimulating Factor on Endometrium and Blood Flow Parameters in Patients With Thin Endometrium: A Prospective Controlled Clinical Trial]

Objective

To investigate the effects of intrauterine perfusion with granulocyte colony-stimulating factor (G-CSF) on the endometrial thickness, volume, and blood flow parameters of patients with thin endometrium and their clinical outcomes.

Methods

We designed a prospective non-randomized synchronous controlled trial and recruited patients with thin endometrium who underwent frozen-thawed embryo transfer (FET) at Mianyang Central Hospital between September 1, 2021 and September 1, 2023. They were divided into two groups, an experimental group of patients who received the experimental treatment of intrauterine perfusion with G-CSF and a control group of patients who did not receive the experimental treatment. The general data and the clinical outcomes of the two groups were analyzed and compared. The endometrial thickness, volume and blood flow parameters of patients in the experimental group before and after intrauterine perfusion with G-CSF were analyzed.

Results

The clinical data of 83 patients were included in the study. The experimental group included 51 cases, while the control group included 31 cases. There were no significant differences in the baseline data between the two groups. The clinical pregnancy rate of the experimental group (56.86%) was higher than that of the control group (50.00%) and the rate of spontaneous abortion in the experimental group (27.59%) was lower than that in the control group (37.50%), but the differences were not statistically significant (P>0.05). In the experimental group, the postperfusion endometrial thickness ([0.67±0.1] cm) was greater than the preperfusion endometrial thickness ([0.59±0.09] cm), the postperfusion ([1.84±0.81] cm3) was greater than the preperfusion endometrial volume ([1.54±0.69] cm3), and the postperfusion vascularization flow index (VFI) (1.97±2.82) was greater than the preperfusion VFI (0.99±1.04), with all the differences being statistically significant (P<0.05).

Conclusion

Intrauterine perfusion with G-CSF can enhance the endometrial thickness, volume, and some blood flow parameters in patients with thin endometrium.

Variation in the AA-NAT gene G203A is associated with Awassi and Hamdani sheep fertility

Arylalkylamine-N-acetyl-transferase (AA-NAT) is one of several genes that influence sheep reproduction. Thus, the objective of this study was to investigate whether genetic variability within the AA-NAT gene influenced the reproductive performance of Awassi and Hamdani ewes. A total of 99 twin and 101 single-progeny ewes were analyzed for genomic DNA. Polymerase chain reaction (PCR) was used to produce amplicons of 300, 313, and 287 bp from exons 1, 2, and 3 of the AA-NAT gene. A 300-bp amplicon was genotyped, resulting in two genotypes: GG and GA. Through sequence analysis, a mutation 203 G > A was identified in the GA genotype. The statistical analysis revealed a strong correlation between the single nucleotide polymorphism (SNP) 203 G > A and reproductive performance. Ewes carrying this mutation showed significantly increased litter sizes, twinning rates, lambing rates, and fewer days to lambing compared to those carrying GG. These findings demonstrate that the presence of the 203 G > A SNP variant has a significant positive impact on litter sizes and enhances the fertility of Awassi and Hamdani sheep.

Melatonin alleviates the toxic effect of di(2-ethylhexyl) phthalate on oocyte quality resulting from CEBPB suppression during primordial follicle formation

Presently, the exposure of plasticizers to humans and animals occurs daily, which pose a potential threat to reproductive health. In the present study, a pregnant mouse model exposed to di(2-ethylhexyl) phthalate (DEHP, one of the most common plasticizers) and melatonin was established, and the single-cell transcriptome technology was applied to investigate the effects of melatonin in ovarian cells against DEHP. Results showed that DEHP markedly altered the gene expression pattern of ovarian cells, and severely weakened the histone methylation modification of oocytes. The administration of melatonin recovered the expression of LHX8 and SOHLH1 proteins that essential for primordial follicle formation, and increased the expression of CEBPB, as well as key genes of histone methylation modification (such as Smyd3 and Kdm5a). In addition, the ovarian damage caused by DEHP was also relieved after the overexpression of CEBPB, which suggested melatonin could improve primordial follicle formation progress via enhancing CEBPB expression in mice. Besides, the apoptosis of ovarian cells induced by DEHP also was diminished by melatonin. The study provides evidence of melatonin preventing the damage mediated by plasticizers on the reproductive system in females and CEBPB may serve as a downstream target factor of melatonin in the process.

A higher number of exhausted local PD1+, but not TIM3+, NK cells in advanced endometriosis

Endometriosis (EMT) is a chronic inflammatory disease characterized by the presence and growth of endometrial-like glandular epithelial and stromal cells outside the uterus. Natural Killer (NK) cell dysfunction/exhaustion has been shown in patients with EMT. In this case-control study, we compared the frequency of exhausted PD-1 or TIM-3 positive NK cells in peripheral blood (PB) and peritoneal fluid (PF) of women with advanced endometriosis to control fertile women. PB and PF were collected from women aged 25-40 who underwent the laparoscopic procedure, including 13 stages III/IV endometriosis and 13 control samples. Multicolor flowcytometry was used to compare the frequency of PD-1 or TIM-3 positive NK (CD3-CD56+) cells in PB and PF of two groups. We demonstrated a higher percentage of PD-1+ NK cells in the peritoneal fluid of patients with endometriosis rather than controls (P-value = 0.039). This significance was related to stage IV of endometriosis (P-value = 0.047). We can not show any significant difference in the number of PD-1 or TIM-3 positive NK cells in peripheral blood. Our results suggest a local exhausted NK cell response in endometriosis that can be a leading factor in the endometriosis pathogenesis.

In vitro culture of sheep early-antral follicles: Milestones, challenges and future perspectives

Early antral follicles (EAFs) represent the transitional stage between pre-antral and antral follicles, containing oocytes that have completed most of their growth phase. Therefore, they offer an easily exploitable reserve for producing mature oocytes and preserving genetic resources, given their higher abundance compared to antral follicles (AFs) and shorter culture period than other pre-antral follicles (PAFs). Despite these advantages, the culture of EAFs remains challenging, and the success rates of in vitro embryo production (IVEP) from EAF-derived oocytes are still far below the standard achieved with fully grown oocytes in ruminant species. The difficulty is related to developing suitable in vitro culture systems tailored with nutrients, growth factors, and other signaling molecules to support oocyte growth. In this review, we focus on the in vitro development of sheep EAFs to provide an informative reference to current research progress. We also summarize the basic aspect of folliculogenesis in sheep and the main achievements and limitations of the current methods for EAF isolation, in vitro culture systems, and medium supplementation. Finally, we highlight future perspectives and challenges for improving EAF culture outcomes.

The effect of Folic Acid, B12, D, and E Vitamins and Melatonin levels in the follicular fluid taken by the Intracytoplasmic Sperm Injection method on pregnancy

Objective

It has been demonstrated that the composition of the follicular fluid and many internal/external factors affect success in subfertile couples undergoing intracytoplasmic sperm injection (ICSI). We examined the effect of folic acid, B12, D, and E vitamins and melatonin values in follicular fluid on pregnancy in women with low, normal, and high ovarian reserves who underwent ICSI.

Methods

Our study was conducted at Samsun Medical Park Hospital between January 2021 and February 2022. Follicular fluid induction samples were taken from 96 infertile women with low, normal, and high ovarian reserve, and ICSI was applied. Folic acid, B12, D, and E vitamins and melatonin levels were measured in follicular fluid samples by ELISA method. Statistical analyzes were done with SPSS, and ROC curve analyses were used.

Results

Nine people with poor reserve, 19 people with normal reserve and 14 people with high reserve became pregnant. Folic acid, Vitamin-D, B12, E and melatonin levels were lower in those with poor ovarian reserve than in those with normal and high ovarian reserve (p<0.05). According to the pregnancy test, the probability of pregnancy was 43,783 times higher with high levels of folic acid, while it was 8,096 times higher for vitamin D. While vitamin B12 levels were 31,474 times more likely to be pregnancies, vitamin E levels were 35,227 times higher. For melatonin, the values showed that the probability of pregnancy increased by 11,564 times.

Conclusions

High antioxidants may increase the likelihood of conception in infertile women undergoing ICSI. Therefore, couples who will be treated should be advised to increase these markers, especially melatonin in the follicular fluid.

Modulation of Melatonin Receptors Regulates Reproductive Physiology: The Impact of Agomelatine on the Estrus Cycle, Gestation, Offspring, and Uterine Contractions in Rats

Agomelatine is a pharmaceutical compound that functions as an agonist for melatonin receptors, with a particular affinity for the MT1 and MT2 receptor subtypes. Its mode of action is integral to the regulation of diverse physiological processes, encompassing the orchestration of circadian rhythms, sleep-wake cycles, and mood modulation. In the present study, we delve into the intricate interplay between agomelatine and the modulation of estrus cycles, gestation periods, offspring numbers, and uterine contractions, shedding light on their collective impact on reproductive physiology. Both in vivo and in vitro experiments were performed. Wistar Albino rats, divided into four groups: two non-pregnant groups (D1 and D2) and two pregnant groups (G1 and G2). The D1 and G1 groups served as control groups, while the D2 and G2 groups received chronic agomelatine administration (10 mg/kg). Uterine contractions were assessed in vitro using myometrial strips. Luzindole, a melatonin receptor antagonist, was employed to investigate the pathway mediating agomelatine's effects on uterine contractions. In in vivo studies, chronic agomelatine administration extended the diestrus phase (p<0.05) in non-pregnant rats, prolonged the gestational period (p<0.01), and increased the fetal count (p<0.01) in pregnant rats. Additionally, agomelatine reduced plasma oxytocin and prostoglandin-E levels (p<0.01) during pregnancy. In vitro experiments showed that agomelatine dose-dependently inhibited spontaneous and oxytocin-induced myometrial contractions. Luzindole (2 µM) reverse the agomelatine-induced inhibition of myometrial contractions. These findings suggest that agomelatine holds the potential to modulate diverse reproductive parameters during the gestational period, influencing estrus cycling, gestational progression, offspring development, and the orchestration of uterine contractions.

Maternal vitamin D deficiency in early pregnancy and perinatal and long-term outcomes

Background

Vitamin D deficiency is common in pregnant women. Some studies have linked vitamin D deficiency to obstetric complications such as gestational hypertension, gestational diabetes, and preterm birth. Therefore, the objective of this study is to investigate the potential impact of vitamin D deficiency during pregnancy on both perinatal and long-term outcomes.

Methods

In this retrospective study, conducted between 2017 and 2021, we analyzed the data of 1079 singleton pregnant women with no medical or surgical complications prior to pregnancy. We evaluated obstetric and perinatal outcomes, as well as neurodevelopmental outcomes using Bayley-III tests, Gross Motor Function Measure, or chart review.

Results

The maternal serum vitamin D level in the first trimester was 18.2 ± 9.0 ng/mL. Vitamin D deficiency (<20 ng/mL) was found in 308 (62.0%) women in the first trimester, of which 288 women (26.7%) were in the very deficient group (<10 ng/mL). There were no differences in maternal age, body mass index, and previous preterm birth between the group with vitamin D < 10 ng/mL and ≥10 ng/mL group. There were also no differences in the rates of gestational hypertension, gestational diabetes, and preterm birth between the two groups, except for the rate of preterm birth before 37 weeks of gestation, which was significantly higher in the very deficient group (adjusted odds ratios [aOR] = 7.78, 95%CI [2.23-27.12], p = 0.001). In the very deficient group, the risk of developmental delay was also higher (aOR = 4.28, 95%CI [1.40-13.05], p = 0.011).

Conclusions

This is the first study to analyze the effects of maternal vitamin D deficiency during pregnancy on both long-term developmental outcomes and perinatal prognosis. Vitamin D deficiency, defined as a level lower than 10 ng/mL in the first trimester, may increase the risk of preterm birth and developmental delay in children.

The Effect on Inflammation of Adherence to the Mediterranean Diet in Polycystic Ovary Syndrome

PURPOSE OF REVIEW

Polycystic ovary syndrome (PCOS), which is common in women of reproductive age worldwide, is a syndrome that reduces the lifelong quality of life and poses a significant risk for various diseases. PCOS is a combination of symptoms of hyperandrogenism, oligo-anovulation, and polycystic ovarian morphology (PCOM). In PCOS, which is characterized by chronic low-grade inflammation, some inflammatory cytokines are increased. This review aimed to explain possible mechanisms of inflammation in PCOS and the effects of Mediterranean diet components on reducing this inflammation.

RECENT FINDINGS

Although the exact mechanisms of inflammation in PCOS are not yet fully known, it is stated that it is mediated by obesity, insulin resistance, and high androgen concentration. This inflammatory state negatively impacts the risk of future health problems and the quality of life of PCOS. Therefore, strategies to reduce inflammation are thought to be important. Dietary adjustments have important effects in reducing this inflammation and preventing disease. At this point, the Mediterranean diet, which has been proven to have a protective effect against many diseases, draws attention. Among the components of the Mediterranean diet, especially omega-3, antioxidants and dietary fiber may contribute to the reduction of inflammation through different mechanisms. PCOS is characterized by chronic low-grade inflammation, which increases women's risk of health problems, both now and in the future. Reducing inflammation is therefore extremely important, and it can be achieved with adherence to the Mediterranean diet. Inflammation pathways and the effect of the components of the Mediterranean diet in PCOS. AGE, advanced glycation end products; NF-κB, nuclear factor kappa-B. Obesity, insulin resistance, and hyperandrogenism may cause inflammation in PCOS through different mechanisms. Antioxidants, omega-3, and dietary fiber, which are the main components of the Mediterranean diet, may be effective in reducing this inflammation in PCOS. (Created with BioRender.com).

Effects of melatonin on development and hormone secretion of sheep theca cells in vitro

Theca cells (TCs) play a unique role in the structure and function of the ovary. They are not only the structural basis of the follicle but also the androgen-secreting cells in female mammals, which can affect the normal development and atresia of the follicle. The results showed that melatonin receptor (MTR) MT1 and MT2 were expressed on sheep TCs. In the present study, the effects of different concentrations of MT at 0, 10^-10, 10^-8, 10^-6 and 10^-4 M/L on sheep TCs with regards to the antioxidant levels, proliferation, apoptosis and steroid hormone secretion were investigated. The results showed that in sheep TCs, all concentrations of MT significantly decreased reactive oxygen species (ROS) concentration and BAX expression; increased Cat, Sod1, and BCL-2 expression. The proliferation viability of TCs was significantly inhibited in all groups except for 10^-10 M/L MT, and the expression of cyclin D1 and CDK4 was significantly reduced. MT significantly increased StAR expression and progesterone secretion in TCs, but there was no significant effect on androgen secretion and CYP11A1, CYP17A1 and 3β-HSD expression in all groups. MT-induced progesterone secretion was completely inhibited by Luzindole (a nonspecific MT1 and MT2 inhibitor) and partially inhibited by 4p-PDOT (specific MT2 inhibitor). MT-induced progesterone secretion can be inhibited by LY294002 (PI3K/AKT pathway inhibitor). This study indicated that MT inhibits apoptosis and proliferation of in vitro cultured sheep TCs, which has implications for slowing ovarian atresia and aging. MT activates the PI3K/Akt pathway to mediate the synthesis and secretion of progesterone by TCs. This study provides a basis for further exploration of the role of TCs on follicle development and ovarian steroid hormone secretion.

In vitro approach points to a chemotactic effect of melatonin on ram spermatozoa

Sperm orientation mechanisms, such as chemotaxis, are essential for the sperm to reach the oocyte and fertilize it. Melatonin is secreted by the cumulus cells and is also present in the follicular fluid in mammals. The presence of membrane receptors for melatonin in ram spermatozoa, and its proven involvement in the sperm functionality, may suggest a possible role in the guided movement towards the oocyte. Hence, the objective of the present work is to study the in vitro potential chemotactic action of melatonin on ram spermatozoa, analysing the influence of the season (breeding and non-breeding) and the sperm capacitation state. The first experimental approach consisted in the inclusion of melatonin in the upper layer of a swim-up selection method. During the non-breeding season, the presence of melatonin at 100 pM and 1 μM concentrations significantly increased the cell recovery rate, and induced changes in the sperm location of the MT₂ melatonin receptor, compared with the standard swim-up. Moreover, the selected sperm population with 100 pM melatonin presented a higher percentage of capacitated spermatozoa. The greater recovery rate obtained with melatonin could be due to the stimulation of sperm movement in random directions, i.e., a chemokinetic effect, or due to a guided movement (chemotaxis) towards the gradient of the melatonin. To elucidate this issue, together with the study of the influence of the sperm capacitation status, we performed a second experimental approach which consisted in the use of chemotaxis chambers and an open-source software (Open-CASA) that analyses the sperm trajectories towards the hormone gradient and calculates a chemotaxis index (SL index). There was a significant difference between the SL index in the presence of 1 μM melatonin and the control without hormone. This effect was only observed in capacitated spermatozoa with cAMP-elevating agents (Cap-CK samples) obtained during the non-breeding season. These results would point to an in vitro chemotactic effect of melatonin on ram spermatozoa, although chemokinesis cannot be ruled out. Nonetheless, the inclusion of this hormone in the swim-up procedure could enhance the sperm recovery rate.

The effect of melatonin on sheep endometrial epithelial cell apoptosis through the receptor and non-receptor pathways

Melatonin potentially regulates the female animal reproductive function, but its regulatory mechanism in the apoptosis of sheep endometrial epithelial cells (SEECs) remains to be elucidated. In the present study, immunofluorescence staining, western blotting, and quantitative real-time polymerase chain reaction were performed to detect the distribution of melatonin receptors (MT1 and MT2) in the uterus of sheep and the effect of melatonin via the receptor and non-receptor pathways on the apoptosis of SEECs in vitro. The results showed that melatonin inhibits the apoptosis of SEECs to varying degrees to regulate the expression of estrogen receptors (ERs) and progesterone receptors (PGR) via its interaction with MT1 and MT2. In addition, the ER antagonist partially relieved the inhibitory effect of melatonin on the apoptosis of SEECs, while the PGR antagonist did not. Thus, melatonin mediates endometrial epithelial apoptosis through the MT receptors and also by regulating estrogen function. This study provides evidence of the regulatory mechanism of melatonin on the physiological function of the sheep uterus.

Granulosa cells from immature follicles exhibit restricted glycolysis and reduced energy production: a dominant problem in polycystic ovary syndrome

PURPOSE

We hypothesized that immature oocytes are associated with impaired energy production in surrounding granulosa cells (GCs) in polycystic ovary syndrome (PCOS). Thus, this study investigated mitochondrial function, determined expression of glycolytic regulatory enzymes, and measured ATP levels in GCs of PCOS patients.

METHODS

GCs were isolated from forty-five PCOS patients and 45 control women. Intracellular concentration of reactive oxygen species (ROS), mitochondrial membrane potential (Δψm), the rate of glycolysis, total antioxidant capacity (TAC), activities of catalase (CAT) and superoxide dismutase (SOD), and ATP level were measured in GCs. The gene expression and protein levels of glycolytic enzymes (hexokinase, muscular phosphofructokinase, platelet derived phosphofructokinase, and muscular pyruvate kinase) were determined. Association of GC energy level with oocyte maturation was further validated by measuring glycolysis rate and ATP level in GCs isolated from mature and immature follicles from new set of fifteen PCOS patients and 15 controls.

RESULTS

PCOS patients showed higher ROS level, decreased TAC, reduced CAT and SOD activities, and lower Δψm together with reduced expression of key glycolytic enzymes. ATP concentration and biochemical pregnancy were lower in PCOS compared with control group. ATP levels were found to be significantly correlated with ROS and Δψm (r = - 0.624 and r = 0.487, respectively). GCs isolated from immature follicles had significantly lower ATP levels and rate of glycolysis compared with the GCs separated from mature follicles in both PCOS patients and control.

CONCLUSION

Declined energy due to the mitochondrial dysfunction and restrained glycolysis in GCs is associated with the immature oocytes and lower biochemical pregnancy in PCOS.

The therapeutic effect of melatonin on female offspring ovarian reserve and quality in BALB/c mice after exposing their mother to methamphetamine during pregnancy and lactation

Objectives

Nowadays, methamphetamine (METH) abuse as a psychotropic drug is increasing. There is insufficient information about its adverse effects on the ovarian reserve of the next generation. Herein, we tried to investigate the effect of METH abuse during pregnancy and lactation and, subsequently, the therapeutic effect of melatonin on ovarian reserve in offspring.

Materials and Methods

In the present study, BALB/c pregnant female mice were divided into 3 groups: Control, Saline, and METH (5mg/Kg). METH was injected during pregnancy and lactation, and the female offspring of each group was divided into 2 subgroups: A) treated with 10 mg/kg Melatonin daily until puberty (6 weeks old) and B) received distilled water. The animals were sacrificed at 6 weeks of age, and blood samples were collected for hormonal assessments; the right ovaries were removed and fixed for TUNEL and Hematoxylin & Eosin staining, and the left ovaries were removed and stored for gene expression and oxidative stress evaluation.

Results

In the MTEH group, two indicators of ovarian reserve (including anti-Müllerian hormone (AMH) and primordial follicle, and Cyclin D1 (CCND-1) and proliferating cell nuclear antigen (PCNA) genes expression significantly decreased, and the oxidative stress and apoptosis significantly increased in comparison with other groups. After lactation in the MTEH group, melatonin treatment significantly improved the ovarian reserve and gene expression and declined apoptosis and oxidative stress.

Conclusion

METH abuse during pregnancy and lactation decreased ovarian reserve in offspring. The administration of melatonin as an anti-oxidant agent after lactation can counteract the adverse effects of METH on offspring ovaries.

Prenatal kisspeptin antagonist exposure prevents polycystic ovary syndrome development in prenatally-androgenized rats in adulthood: An experimental study

Background

Increased levels of kisspeptin are associated with hypothalamus-pituitary-ovary axis dysfunction. It may lead to the development of polycystic ovary syndrome (PCOS).

Objective

We aimed to investigate the effect of prenatal kisspeptin antagonist exposure on the development of PCOS in prenatally androgenized rats in adulthood.

Materials and Methods

In this experimental study, pregnant rats were injected with free testosterone (T, 5 mg/day) or T+P271 (kisspeptin antagonist) on the 20 th day of the pregnancy period (n = 5 in each group), while rats in the control group received solvent. Female offspring were examined in terms of anogenital distance (AGD), anovaginal distance (AVD), vaginal opening, serum total testosterone (TT) levels, ovarian follicles, and the regularity of estrous cycles in adulthood. AGD and AVD were measured using a vernier caliper. TT levels were measured using the enzyme-linked immunosorbent assay method. Ovaries were fixed in 10% formalin, tissue processing was done by a standard protocol, and then ovaries embedded in paraffin. 5 μm-thickness ovarian sections mounted on a glass slide, deparaffinized, and stained using Harris's Hematoxylin and Eosin Y.

Results

AGD, AVD (p < 0.001), TT levels (p = 0.02), and the numbers of preantral and antral follicles (p < 0.001) in the ovaries were significantly decreased in prenatally T-P271-exposed rats compared to prenatally T-exposed rats. The age of vaginal opening was early in T-P271-exposed rats compared to prenatally T-exposed rats (p < 0.001). The number of corpora lutea was significantly increased in T-P271-exposed rats (p < 0.001). No cystic follicles were observed in the ovaries of prenatally T-P271-exposed rats. Prenatally T-P271-exposed rats had regular estrous cycles compared to prenatally T-exposed rats.

Conclusion

Prenatal exposure to kisspeptin antagonist can prevent PCOS development in prenatally androgenized rats in adulthood.

Dietary flaxseed oil and vitamin E improve semen quality via propionic acid metabolism

Introduction

Flaxseed oil (FO) and vitamin E (VE) both have antioxidant effects on sperm. The present study investigated the effects of dietary supplementation with FO and/or VE on semen quality.

Methods

16 fertile Simmental bulls were selected and randomly divided into 4 groups (n = 4): the control group (control diet), FO group (control diet containing 24 g/kg FO), VE group (control diet containing 150 mg/kg VE) and FOVE group (control diet containing 150 mg/kg VE and 24 g/kg FO), and the trial lasted 10 weeks.

Results

The results showed that the addition of FO independently can increase sperm motion parameters, the levels of catalase (CAT), glutathione peroxidase (GSH-Px), testosterone (T) and estradiol (E2), while reduce oxidative stress in seminal plasma (P < 0.05). Supplement of VE independently can increased the motility, motility parameters, CAT and superoxide dismutase (SOD) levels, and reduce oxidative stress in seminal plasma (P < 0.05). There was an interaction effect of FO × VE on motility and reactive oxygen species (ROS), while GSH-Px and ROS were affected by week × VE 2-way interaction, levels of T and E2 were also affected by the dietary FO × week interaction (P < 0.05). The triple interaction effects of FO, VE and week were significant for malondialdehyde (MDA) (P < 0.05). Compared with the control group, sperm from the FOVE group had a significantly higher in vitro fertilization (IVF) rate, and subsequent embryos had increased developmental ability with reduced ROS levels at the eight-cell stage, then increased adenosine triphosphate (ATP) content and gene expression levels of CAT, CDX2, Nanog, and SOD at the blastocyst stage (P < 0.05). Metabolomic and transcriptomic results indicated that dietary supplementation of FO and VE increased the expression of the metabolite aconitic acid, as well as the expression of ABAT and AHDHA genes.

Conclusion

With in-silico analysis, it can be concluded that the effects of dietary FO and VE on improving semen quality and embryo development may be related to increased aconitic acid via the ABAT and AHDHA genes involved in the propionic acid metabolism pathway.

A novel stop codon mutation in STK11 gene is associated with Peutz-Jeghers Syndrome and elevated cancer risk: a case study

Based on the analysis of patients with Peutz-Jeghers syndrome (PJS), Serine threonine kinase11 (STK11) is known as a tumor suppressor gene, which is involved in cell polarization, regulation of apoptosis, and DNA damage response. In this case report study, we examined STK11 gene sequencing in a 42-year-old woman with mucocuta neous pigmentation and positive family history. Endoscopy and colonoscopy showed >1000 polyps throughout the stomach/colon (PJ-type hamartomas). The larger polyp in the stomach was resected and the small bowel imaging detected multiple jejunum/ileum small polyps. The data released from the sequencing results revealed five alterations in exons 1 to 5. The major mutation in stop codon was reported as converted to the amino acid tryptophan (TRP) to tyrosine (TER). The TGG codon was converted to TAG by mutation. Finally, another novel mutation in STK11 stop codon as a 'de novo' variant was seen. It is predicted that stop codon mutations make the affected person susceptible to developing colorectal cancer.

Pregnancy rate in intrauterine insemination, is uterine biophysical profile of predictive value? A prospective study

PURPOSE

This study aimed at evaluating the value of uterine biophysical profile (UBP) scoring to predict the pregnancy rate after IUI.

METHODS

This prospective study was carried out on 85 women who were referred to our tertiary teaching center with infertility of male factor or unknown etiology infertility in 2018. To measure the uterine biophysical criteria, transvaginal ultrasonography (TVS) was performed on the day of beta-human chorionic gonadotropin (B-hCG) injection, and the results were evaluated based on positive B-hCG.

RESULTS

85 patients were included with a mean age of 30 years; of those 12 (14.1%) were able to conceive. UBP (p = 0.151) and it's parameters (including endometrial thickness, number of endometrial layers, myometrial echogenicity, uterine artery pulsatility index, myometrial blood flow internal to arcuate vessels, endometrial blood flow in the third zone of endometrium, myometrial contraction frequency, and ovarian follicle (OF) size [p = 0.05, 0.89, 0.59, 0.79, 1, 1, 0.59, and 0.77, respectively]) were not significantly associated with pregnancy rate. 91.7% of the cases with positive pregnancy test results, had a UBP score of > 13; however, UBP score was not meaningfully associated with IUI treatment success rate (p = 0.15).

CONCLUSIONS

UBP scoring system seems to need more data for external validation, or it might require modifications before implementation, as it may cause false reassurance.

Immunolocalization of melatonin receptors in bovine ovarian follicles and in vitro effects of melatonin on growth, viability and gene expression in secondary follicles

This study aims to investigate the (1) expression of melatonin receptors types 1A/B (MTNR1A/B) in bovine ovaries and (2) the in vitro effects of melatonin on secondary follicle development, antrum formation, viability, and expression of messenger ribonucleic acid (mRNA) for superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase-1 (GPX1) and peroxiredoxin 6 (PRDX6). The expression of MTNR1A/B in bovine ovarian follicles was demonstrated by immunohistochemistry. To choose the most effective concentration of melatonin on follicular growth and viability, isolated secondary follicles were cultured individually at 38.5°C, with 5% CO₂ in air, for 18 d in TCM-199⁺ alone or supplemented with 10^-11, 10^-9, 10^-7 or 10^-5 M melatonin. Then, melatonin receptor antagonist, luzindole, was tested to further evaluate the mechanisms of actions of melatonin, that is, the follicles were cultured in control medium alone or supplemented with 10^-7 M melatonin, 10 µM luzindole and both 10^-7 M melatonin and 10 µM luzindole. Follicular growth, morphology and antrum formation were evaluated at days 6, 12 and 18. At the end of culture, viability of secondary follicles was analyzed by calcein-AM and ethidium homodimer-1, and the relative levels of mRNA for SOD, CAT, GPX1 and PRDX6 were evaluated by real time polymerase chain reaction. Immunohistochemistry results showed expression of MTNR1A/B in oocyte and granulosa cells of primordial, primary, secondary and antral follicles. Secondary follicles cultured in medium supplemented with melatonin at different concentrations had well preserved follicles after 18 d of culture. Furthermore, follicles cultured in presence of 10^-7 M melatonin presented significantly higher diameters than those cultured in other treatments. The presence of melatonin receptor antagonist, luzindole, blocked the effects of melatonin on follicular growth and viability. In addition, follicles cultured in medium containing only melatonin had significantly higher rates of antrum formation. Follicles cultured in medium containing only melatonin had higher relative levels of mRNA for CAT, SOD and PRDX-6 than those cultured with both melatonin and luzindole. Follicles cultured with luzindole only or both melatonin and luzindole had lower relative levels of mRNA for PRDX6 and GPX1 than those cultured control medium. In conclusion, melatonin promotes growth of bovine secondary follicles through its membrane-coupled receptors, while luzindole blocks the effects of melatonin on follicle growth and reduces the expression of antioxidant enzymes in cultured follicles.

Investigation of the endometrial receptivity status in experimental hypothyroid-induced female rats

OBJECTIVES

This study aimed to investigate hypothyroidism's effects on endometrial receptivity, creating an experimental hypothyroidism model in female rats.

MATERIALS AND METHODS

To induce hypothyroidism in rats of Hipotiroid-ER and Treatment-ER groups, 0.05% 6-propyl-2-thiouracil was freshly added to their drinking water for 8 weeks and then the endometrial receptivity model was applied and sacrificed on the fifth day. In the Treatment-ER group, after sc-administration of 0.8 µg/100 g L-thyroxine for 10 days, the endometrial receptivity model was applied to the rats and sacrificed on the fifth day.

RESULTS

In the histopathological evaluation, epithelial degeneration, vacuolization, enlargement of the uterine glands, and morphological disorders were observed in the endometrial layer of the Hypothyroid-ER group. However, these pathologies were significantly alleviated in the Treatment-ER group. Integrin β3, integrin αvβ3, LIF, and HOXA10 immune reaction intensities were high in the Control-ER and Treatment-ER groups, while in the Hypothyroid-ER group, integrin β3, integrin αvβ3, LIF, and HOXA10 immunoreactivity intensities were low. Also, while MUC1 immunoreactivity was high in the Hypothyroid-ER group, it was low in the other groups. In biochemical analysis, a significant increase in the TSH and progesterone levels and a significant decrease in the FT4, E2, FSH, and LH levels in the Hypothyroid-ER group compared with the Control-ER group were observed. Also, all hormone levels were significantly ameliorated in the rats of the Treatment-ER group compared with the Hypothyroid-ER group.

CONCLUSION

The results obtained showed that hypothyroidism had a significant effect on endometrial receptivity-the histopathological and biochemical changes caused by hypothyroidism in the experimental rat model were ameliorated with L-thyroxine treatment.

Immunolocalization of melatonin receptor type 1 in the sheep ovary and involvement of the PI3K/Akt/FOXO3a signaling pathway in the effects of melatonin on survival and in vitro activation of primordial follicles

This study characterized the expression of melatonin receptor type 1 (MT₁ ) protein in sheep ovaries, evaluated melatonin effects on primordial follicle survival and development after in vitro culture of ovarian tissue and verified the possible involvement of the phosphatidylinositol-3-kinase/protein kinase B/forkhead box O3a (PI3K/Akt/FOXO3a) pathway in the melatonin actions. Ovine ovarian fragments were cultured in α-modified minimum essential medium alone (α-MEM⁺ ) or supplemented with 100, 500, or 1000 pg/ml melatonin for 7 days. PI3K inhibition was performed through pretreatment of ovarian fragments with LY294002. Thereafter, immunohistochemistry was performed to evaluate the expression of cleaved caspase-3, Akt, phosphorylated-Akt, and phosphorylated-FOXO3a (p-FOXO3a). The immunohistochemical localization of the MT₁ receptor protein was documented in sheep preantral and antral follicles. After in vitro culture, 100 pg/ml melatonin showed higher follicular survival and activation than α-MEM⁺ and other melatonin concentrations. After PI3K inhibition, there was an increase in cleaved caspase-3-positive follicles, and a decrease in the primordial follicle activation, Akt phosphorylation, and nuclear exclusion of p-FOXO3a. In conclusion, MT₁ receptor protein is present in the sheep ovary. Furthermore, 100 pg/ml melatonin maintains survival and stimulates activation of primordial follicles through the PI3K/Akt/FOXO3a signaling pathway after in vitro culture of sheep ovarian tissue.

Effects of high-fat diet on thyroid autoimmunity in the female rat

BACKGROUND

While contributions of dyslipidemia to autoimmune diseases have been described, its impact on thyroid autoimmunity (TA) is less clear. Programmed cell death 1(PD-1)/PD-ligand 1 (PD-L1) immune checkpoint is crucial in preventing autoimmune attack while its blockade exacerbates TA. We thus unveiled the effect of high-fat diet (HFD) on TA, focusing on the contribution of PD-1/PD-L1.

METHODS

Female Sprague Dawley (SD) rats were randomly fed with a regular diet or HFD (60% calories from fat) for 24 weeks. Then, thyroid ultrasonography was performed and samples were collected for lipid and thyroid-related parameter measure.

RESULTS

HFD rats exhibited hyperlipemia and abnormal biosynthesis of the unsaturated fatty acid in serum detected by lipidomics. These rats displayed a relatively lower echogenicity and increased inflammatory infiltration in thyroid accompanied by rising serum thyroid autoantibody levels and hypothyroidism, mimicking human Hashimoto's thyroiditis. These alterations were concurrent with decreased mRNA and immunostaining of intrathyroidal PD-1 and also serum PD-1 levels but not the PD-L1 expression, suggesting a role of a PD-1 pathway. Meanwhile, the infiltration of B and T cell, a key cellular event inhibited by the PD-1 signals, was enhanced in the thyroid of HFD rats, along with thyroid fibrosis and apoptosis.

CONCLUSIONS

Our data suggest that HFD triggers TA through a mechanism possibly involving downregulation of PD-1-related immunosuppression, providing a novel insight into the link between dyslipidemia and autoimmune toxicities.

Melatonin Receptors: A Key Mediator in Animal Reproduction

Melatonin, a hormone produced by the mammalian pineal gland, influences various physiological activities, many of which are related to animal reproduction, including neuroendocrine function, rhythm regulation, seasonal behavior, gonadogenesis, gamete development and maturation, sexual maturation, and thermoregulation. Melatonin exerts beneficial actions mainly via binding with G-protein-coupled receptors (GPCR), termed MT1 and MT2. Melatonin receptors are crucial for mediating animal reproduction. This paper reviews the characteristics of melatonin receptors including MT1 and MT2, as well as their roles in mediating signal transduction and biological effects, with a focus on their function in animal reproduction. In addition, we briefly summarize the developments in pharmacological research regarding melatonin receptors as drug targets. It is expected that this review will provide a reference for further exploration and unveiling of melatonin receptor function in reproductive regulation.

Exogenous Melatonin Directly and Indirectly Influences Sheep Oocytes

Understanding whether and how melatonin (MT) may impact sheep oocyte development competence is central to our ability to predict how sheep oocytes will respond to artificially regulated estrus. Implanting MT can make sheep enter estrus during the non-breeding season. One study found that the blastocyst rate increased under MT treatment, while another found that the blastocyst rate decreased. Therefore, we conducted a meta-analysis of MT directly and indirectly influencing sheep oocytes. A total of 433 articles were collected from which 20 articles and 34 treatments were finally selected. A method for estimating the default value was established for the litter size analysis. We found that exogenous MT add into in vitro maturation medium was positively related to the blastocyst rate in the lab. However, subcutaneous implanting MT did not affect the in vivo ovulation rate, fertilization rate, blastocyst rate, or pregnancy rate at farm. MT did not affect the in vitro cleavage rate. However, MT improved the in vivo cleavage rate. We hypothesized that implanted MT could increase the concentration of MT in oviduct fluid in vivo, and also that in vitro MT could increase the early cleavage rate of sheep zygotes without affecting the total cleavage rate. In the analysis of oocyte apoptosis caused by injury, the results suggested that pyroptosis would be more suitable for further research. MT produces responses in all body organs, and thus implanting of MT during non-breeding seasons should consider the effect on animal welfare.

Environmental remediation using metals and inorganic and organic materials: a review

In recent times, environmental pollution has been an alarming concern. This is increasing day-in-and-day-out, especially in the Asia-Pacific region due to the increasing population, urbanization, industrialization and inappropriate waste management measures. Pollution abatement is the need of the hour to sustain the biosphere in general and the human life in particular. A range of physical, chemical and biological strategies are commonly employed to remove pollutants from the contained water, soil and air. Physical, chemical or physicochemical remediation processes are commonly employed owing to their high efficiency, stability, recyclable property and low procurement cost as compared to metals, inorganic and organic materials. Materials of the later type include biocomposites, thin films, modified (bio)polymers, nanoparticles, nanofilters, sorbent like activated charcoal, and carbon nanotubes and nanosensors. Remediation mechanism largely follows sorption, degradation, oxidation, reduction, catalytic conversion, detection and microbial toxicity principles. This review details the mechanisms of action by these various remediating entities, their successful applications in pollution abatement, drawbacks and future prospects.HighlightsEnvironmental remediation using metals, inorganic and organic materials are discussed extensively.Major remediating approaches, viz., physical, physicochemical and chemical are elaborated citing latest references.The significance of biocomposites, biopolymers, polymers, thin films, nanoparticles, nanofilters, nanosensors and sorbents in remediation are highlighted.Pollutant removal from water, air and soil has been precisely discussed.A note on drawbacks, improvement and future prospects of remediating agents is presented.

The need to identify novel biomarkers for prediction of premature ovarian insufficiency (POI)

Background

Premature ovarian failure (POF)/premature ovarian insufficiency (POI) is characterized by disrupting ovarian function under 40 years old. A major health problem of this disorder is female infertility. There are no proven treatments to increase the rate of pregnancy with autologous oocytes in these patients. This review aims to summarize our present knowledge about POI-induced infertility treatments and to highlight the importance of future researches in the discovery of diagnostic biomarkers and treatment of patients with this disorder.

Methods

A literature review was carried out using PubMed and Google Scholar databases by relevant keywords, such as POI, POF, premature ovarian failure, premature ovarian insufficiency, and biomarkers.

Results

Two hundred three studies were included in the study following the search for the keywords. Titles and abstracts of the identified articles were evaluated for detecting relevant full-length articles.

Conclusion

Anti-Mullerian hormone (AMH) level appears to have considerable value as a diagnostic test for POI, but it is not reliable enough to be able to predict accurately the timing of onset of impending POI. Using an accurate biomarker, POI can be diagnosed early and infertility treatment that is concerned about can be done on time. Biomarkers in combination with other diagnostic tests could result in prediction of POI before the development of complete ovarian failure.

The Crosstalk between Melatonin and Sex Steroid Hormones

Melatonin, an indolamine mainly released from the pineal gland, is associated with many biological functions, namely, the modulation of circadian and seasonal rhythms, sleep inducer, regulator of energy metabolism, antioxidant, and anticarcinogenic. Although several pieces of evidence also recognize the influence of melatonin in the reproductive physiology, the crosstalk between melatonin and sex hormones is not clear. Here, we review the effects of sex differences in the circulating levels of melatonin and update the current knowledge on the link between sex hormones and melatonin. Furthermore, we explore the effects of melatonin on gonadal steroidogenesis and hormonal control in females. The literature review shows that despite the strong evidence that sex differences impact on the circadian profiles of melatonin, reports are still considerably ambiguous, and these differences may arise from several factors, like the use of contraceptive pills, hormonal status, and sleep deprivation. Furthermore, there has been an inconclusive debate about the characteristics of the reciprocal relationship between melatonin and reproductive hormones. In this regard, there is evidence for the role of melatonin in gonadal steroidogenesis brought about by research that shows that melatonin affects multiple transduction pathways that modulate Sertoli cell physiology and consequently spermatogenesis, and also estrogen and progesterone production. From the outcome of our research, it is possible to conclude that understanding the correlation between melatonin and reproductive hormones is crucial for the correction of several complications occurring during pregnancy, like preeclampsia, and for the control of climacteric symptoms.

Melatonin supplementation in the culture medium rescues impaired glucose metabolism in IVF mice offspring

Increasing evidence suggests that in vitro fertilization (IVF) may be associated with an increased risk of developing obesity and metabolic diseases later in life in the offspring. Notably, the addition of melatonin to culture medium may improve embryo development and prevent cardiovascular dysfunction in IVF adult mice. This study aimed to determine if melatonin supplementation in the culture medium can reverse impaired glucose metabolism in IVF mice offspring and the underlying mechanisms. Blastocysts used for transfer were generated by natural mating (control group) or IVF with or without melatonin (10^-6  M) supplementation (mIVF and IVF group, respectively) in clinical-grade culture media. Here, we first report that IVF decreased hepatic expression of Fbxl7, which was associated with impaired glucose metabolism in mice offspring. Melatonin addition reversed the phenotype by up-regulating the expression of hepatic Fbxl7. In vitro experiments showed that Fbxl7 enhanced the insulin signaling pathway by degrading RhoA through ubiquitination and was up-regulated by transcription factor Foxa2. Specific knockout of Fbxl7 in the liver of adult mice, through tail intravenous injection of recombinant adeno-associated virus, impaired glucose tolerance, while overexpression of hepatic Fbxl7 significantly improved glucose tolerance in adult IVF mice. Thus, the data suggest that Fbxl7 plays an important role in maintaining glucose metabolism of mice, and melatonin supplementation in the culture medium may rescue the long-term risk of metabolic diseases in IVF offspring.

Regulatory role of melatonin on epidermal growth factor receptor, Type I collagen α1 chain, and caveolin 1 in granulosa cells of sheep antral follicles

We investigated the expression of epidermal growth factor receptor (EGFR), Type I collagen α1 chain (COL1A1), and caveolin 1 (CAV1) during follicular development and examined the regulatory role of melatonin (MLT) on EGFR, COL1A1, and CAV1 in sheep antral ovaries. The expression was detected in granulosa and theca cells by immunohistochemistry. Quantitative real-time polymerase chain reaction and Western blotting were used to examine the expression levels of EGFR, COL1A1, and CAV1 in small (≤2 mm), medium (2-5 mm), and large (≥5 mm) follicles. The mRNA and protein levels of EGFR, COL1A1, and CAV1 were found to be the highest in large follicles. Furthermore, cultured granulosa cells were treated with MLT (10^-7 -10^-11  M), luzindole (nonselective MT1 and MT2 receptor antagonist, 10^-7  M), and 4-phenyl-2-propanamide tetraldehyde (4P-PDOT, MT2 selective antagonist, 10^-7  M) to detect the regulatory role of MLT on EGFR, COL1A1, and CAV1. Results indicated COL1A1 and CAV1 were at least partially regulated by MLT through MT1 and MT2 pathways, whereas EGFR was not. This study provided a reference for further studies on MLT regulatory role on EGFR, COL1A1, and CAV1 during sheep follicular development and elucidated the physiological mechanism of MLT regulator production.

β-Estradiol inhibits melatonin synthesis and melatonin receptor expression in sheep granulosa cells

Melatonin, an important regulator of mammalian reproduction, is mainly produced in the pineal gland, and granulosa cells (GCs), the main mammalian ovarian secretory cells, synthesize melatonin and express melatonin receptors (MRs) MT1 and MT2. However, studies on melatonin regulation in GCs are lacking in sheep. In this study, we explored the effects of β-estradiol (E2) on melatonin production and MR expression in GCs. We cultured sheep GCs to analyze the expression of the melatonin rate-limiting enzymes AANAT and HIOMT and the effects of E2 on AANAT, HIOMT, and MR expression and melatonin synthesis. To determine whether estrogen receptors (ERs) mediated E2 action on melatonin secretion and MR expression, we assessed ERA and ERB expression in GCs and observed whether ER antagonists counterbalanced the effects of E2. GCs expressed AANAT and HIOMT mRNA, indicating that they transformed exogenous serotonin into melatonin. E2 inhibited melatonin production by downregulating AANAT, HIOMT, and MRs. GCs expressed ERA and ERB; ERA/ERB inhibitors abolished E2-mediated inhibition of melatonin secretion and MR expression. PHTPP upregulated melatonin secretion and MT1 expression in E2-treated GCs, but did not significantly affect AANAT and MT2 expression. In conclusion, melatonin secretion in GCs was inhibited by E2 through an ERA- and ERB-mediated process.

Effects of prematuration culture with a phosphodiesterase-3 inhibitor on oocyte morphology and embryo quality in in vitro maturation

Objective

The study assessed the developmental potential of germinal vesicle (GV) oocytes subjected to in vitro maturation (IVM) after prematuration culture with cilostamide (a phosphodiesterase-3 inhibitor) and the impact of cilostamide exposure on the morphology of meiosis II (MII) oocytes and subsequent embryo quality.

Methods

In total, 994 oocytes were collected from 63 patients. Among 307 GV oocytes, 140 oocytes were selected for the experimental group and 130 oocytes for the control group. The denuded GV-stage oocytes were cultured for 6 hours with cilostamide in the experimental group and without cilostamide in the control group. After 6 hours, the oocytes in the experimental group were washed and transferred to fresh IVM medium. The maturational status of the oocytes in both groups was examined at 26, 36, and 48 hours. Fertilization was assessed at 18 hours post-intracytoplasmic sperm injection. Embryo quality was assessed on days 3 and 5.

Results

In total, 92.1% of the oocytes remained in the GV stage, while 6.4% converted to the MI stage (p<0.01) after cilostamide exposure. In both groups, more MII oocytes were observed at 36 hours (25.8% vs. 21.5%) than at 26 hours (10.8% vs. 14.6%) and 48 hours (13% vs. 7.9%) (p>0.05). With the advent of cilostamide, blastocyst quality was better in the experimental group than in the control group (p<0.05).

Conclusions

Cilostamide effectively blocked nuclear maturation and promoted cytoplasmic growth. Prematuration culture with cilostamide enabled synchronization between cytoplasmic and nuclear maturity, resulting in better blastocyst outcomes.

Meta-analysis of melatonin treatment and porcine somatic cell nuclear transfer embryo development

Porcine somatic cell nuclear transfer (SCNT) plays an important role in many areas of research. However, the low efficiency of SCNT in porcine embryos limits its applications. Porcine embryos contain high concentrations of lipid, which makes them vulnerable to oxidative stress. Some studies have used melatonin to reduce reactive oxygen species damage. At present there are many reports concerning the effect of exogenous melatonin on porcine SCNT. Some studies suggest that the addition of melatonin can increase the number of blastocyst cells, while others indicate that melatonin can reduce the number of blastocyst cells. Therefore, a meta-analysis was carried out to resolve the contradiction. In this study, a total of 63 articles from the past 30 years were analyzed, and six papers were finally selected. Through the analysis, it was found that the blastocyst rate was increased by adding exogenous melatonin. Melatonin had no effect on cleavage rate or the number of blastocyst cells, but did decrease the number of apoptotic cells. This result is crucial for future research on embryo implantation.

4-Pentenoyl-isoleucyl-chitosan oligosaccharide and acrylamide functional monomer-dependent hybrid bilayer molecularly imprinted membrane for sensitive electrochemical sensing of bisphenol A

In this work, an electrochemical sensor was designed for trace monitoring of bisphenol A (BPA) by decorating a hybrid bilayer molecularly imprinted membrane (MIM) on a multi-walled carbon nanotube-modified glassy carbon electrode. When BPA in the MIM was eluted, a composite molecularly imprinted electrochemical sensor was constructed. Under optimal conditions, the developed sensor showed two linear relationships between ΔI p and BPA concentration in the range of 0.04 μM to 8 μM, as well as good selectivity and stability, and was also applied to detect BPA in water samples with desirable recoveries ranging from 92.0% to 107.0%.

Ovarian activation delays in peripubertal ewe lambs infected with Haemonchus contortus can be avoided by supplementing protein in their diets

BACKGROUND

The ewe lamb nutritional and physiological state interfere with the ovarian environment and fertility. The lack or excess of circulating nutrients reaching the ovary can change its gene expression. A protein deficiency in the blood caused by an Haemonchus contortus abomasal infection is detrimental to the organism's development during puberty. The peripubertal period is a time of intensive growth that requires a high level of nutrients. An essential feature controlling pubertal arousal and female reproductive potential is ovarian follicle growth activation. Protein supplementation improves the sheep's immune response to helminthic infections. We aimed to determine if supplementing protein in infected ewe lambs' diet would impact the ovarian environment leading to earlier ovarian follicle activation than in infected not supplemented animals.

METHODS

We fed 18 Santa Ines ewe lambs (Ovis aries) - bred by the same ram - with either 12% protein (Control groups) or 19% protein (Supplemented groups) in their diets. After 35 days of the diet, they were each artificially infected or not with 10,000 Haemonchus contortus L3 larvae. Following 77 days of the diet and 42 days of infection, we surgically collected their left ovaries and examined their genes expression through RNA sequencing.

RESULTS

We found that protein supplementation in infected animals led to an up-regulation of genes (FDR p-values < 0.05) and biological processes (p-value cut-off = 0.01) linked to meiotic activation in pre-ovulatory follicles and primordial follicle activation, among others. The supplemented not infected animals also up-regulated genes and processes linked to meiosis and others, such as circadian behaviour. The not supplemented animals had these same processes down-regulated while up-regulated processes related to tissue morphogenesis, inflammation and immune response.

CONCLUSION

Diet's protein supplementation of peripubertal infected animals allowed them to express genes related to a more mature ovarian follicle stage than their half-sisters that were not supplemented. These results could be modelling potential effects of the interaction between environmental factors, nutrition and infection on reproductive health. When ovarian activation is achieved in a timely fashion, the ewe may generate more lambs during its reproductive life, increasing sheep breeders' productivity.

Autophagy in ovary and polycystic ovary syndrome: role, dispute and future perspective

Polycystic ovary syndrome (PCOS) is a unification of endocrine and metabolic disorders and has become immensely prevalent among women of fertile age. The prime organ affected in PCOS is the ovary and its distressed functioning elicits disturbed reproductive outcomes. In the ovary, macroautophagy/autophagy performs a pivotal role in directing the chain of events starting from oocytes origin until its fertilization. Recent discoveries demonstrate a significant role of autophagy in the pathogenesis of PCOS. Defective autophagy in the follicular cells during different stages of follicles is observed in the PCOS ovary. Exploring different autophagy pathways provides a platform for predicting the possible cause of altered ovarian physiology in PCOS. In this review, we have emphasized autophagy's role in governing follicular development under normal circumstances and in PCOS, including significant abnormalities associated with PCOS such as anovulation, hyperandrogenemia, metabolic disturbances, and related abnormality. So far, few studies have linked autophagy and PCOS and propose its essential role in PCOS progression. However, detailed knowledge in this area is lacking. Here we have summarized the latest knowledge related to autophagy associated with PCOS. This review's main objective is to provide a background of autophagy in the ovary, its possible connection with PCOS and suggested a novel proposal for future studies to aid a better understanding of PCOS pathogenesis.Abbreviations: AE: androgen excess; AF: antral follicle; AKT/PKB: AKT serine/threonine kinase; AMH: anti-Mullerian hormone; AMPK: AMP-activated protein kinase; ATG: autophagy-related; BCL2: BCL2 apoptosis regulator; BECN1: beclin 1; BMP: bone morphogenetic protein; CASP3: caspase 3; CL: corpus luteum; CYP17A1/P450C17: cytochrome P450 family 17 subfamily A member 1; CYP19A1: cytochrome P450 family 19 subfamily A member 1; DHEA: dehydroepiandrosterone; EH: endometrial hyperplasia; FF: follicular fluid; FOXO: forkhead box O; FSH: follicle stimulating hormone; GC: granulosa cell; GDF: growth differentiation factor; HA: hyperandrogenemia; HMGB1: high mobility group box 1; IGF1: insulin like growth factor 1; INS: insulin; IR: insulin resistance; LHCGR/LHR: luteinizing hormone/choriogonadotropin receptor; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MAPK/ERK: mitogen-activated protein kinase; MAPK8/JNK: mitogen-activated protein kinase 8; MTOR: mechanistic target of rapamycin kinase; MTORC: mechanistic target of rapamycin complex; NAFLD: nonalcoholic fatty liver disease; NFKB: nuclear factor kappa B; OLR1/LOX-1: oxidized low density lipoprotein receptor 1; oxLDL: oxidized low-density lipoproteins; PA: palmitic acid; PCOS: polycystic ovary syndrome; PF: primary follicle; PGC: primordial germ cell; PI3K: phosphoinositide 3-kinase; PMF: primordial follicle; ROS: reactive oxygen species; RP: resting pool; SIRT1: sirtuin 1; SQSTM1/p62: sequestosome 1; T2DM: type 2 diabetes mellitus; TC: theca cell; TUG1: taurine up-regulated 1.

Photoperiodic modulation of ovarian metabolic, survival, proliferation and gap junction markers in adult golden hamster, Mesocricetus auratus

Female reproductive physiology is greatly dependent on tight regulation of metabolic and survival factors. Photoperiod regulates female reproductive rhythms but very less information exists explaining whether photoperiod could modulate thyroid hormone homeostasis, metabolic/energy parameters along with survival, proliferation and gap junction proteins in the ovary of a long-day breeder, Mesocricetus auratus. Adult female hamsters were exposed to different photoperiodic regimes i.e., critical photoperiod (CP; 12.5L:11.5D), short photoperiod (SP; 8L:16D) and long photoperiod (LP; 16L:8D) for 12 weeks. LP upregulated thyroidal and gonadal activity as apparent by histoarchitecture, thyroid hormone profile [triiodothyronine (T3), thyroxin (T4) and thyroid stimulating hormone (TSH)], luteinizing hormone (LH), follicle stimulating hormone (FSH), estradiol (E2) and progesterone (P4) levels when compared with SP exposed hamsters. Further, LP increased thyroid hormone receptor-α/deiodinase-2 (TRα/Dio-2), estrogen receptor-α (ERα)/aromatase and insulin receptor/glucose transporter-4 (IR/GLUT-4) expressions in ovary. Interestingly, ovarian sirtuin-1 (SIRT-1) expression was also upregulated under LP condition along with cell proliferation (proliferating cell nuclear antigen or PCNA), survival (B cell lymphoma-2 or Bcl-2) and gap junction (connexin-43) markers when compared to SP exposed hamsters. We also noted elevated levels of circulatory leptin, insulin along with melatonin and its receptor (MT-1) in ovary under SP condition. Thus, we suggest that photoperiod plays a vital role in regulation of thyroid and reproductive hormone homeostasis along with key metabolic and survival markers in the ovary of adult golden hamsters, M. auratus providing further insight into the regulation of female reproductive seasonality in a long-day breeder.

Melatonin: A regulator of the interplay between FoxO1, miR96, and miR215 signaling to diminish the growth, survival, and metastasis of murine adenocarcinoma

Melatonin (Mel.), also known as the magic hormone, is a nocturnally secreted hormone orchestrates the clearance of free radicals that have been built up and cumulated during day. This study aims to detect the impact of pineal gland removal on the incidence of tumor development and to assess the signaling pathways via which exogenous melatonin counteract cancer growth. This goal has been achieved by novel approach for pineal destruction using dental micromotor which validated by melatonin downregulation in blood plasma. Mice were injected sub-cutenously with Ehrlich cells to develop solid tumor as a murine model of breast cancer. The increase at tumor markers carcino embryonic antigen, TNFα, and nuclear factor kappa-light-chain-enhancer of activated B cells was over countered by exogenous melatonin supplementation (20 mg/kg) daily for 1 month. The anticancer effects of melatonin were significantly mediated by scavenging H₂ O₂ and NO and diminishing of lipid peroxidation marker malondialdehyde. The real-time polymerase chain Rx analyses indicated a significant effect of Melatonin in upregulating the expression of miR215, fork head box protein O1 (foxO1), and downregulation of miR96. Flowcytometric analyses indicated a significant effect of melatonin on induction of cell cycle arrest at G1 phase which was further confirmed by Ki67 downregulation. Immunohistochemical analyses indicated the role of melatonin in upregulating P53-dependent apoptosis and downregulating CD44 signaling for survivin, matrix metallo-protein kinase 2, and vascular endothelial growth factor to inhibit cell survival and metastasis. In conclusion, this study sheds the light on M./P53/miR215/CD44 with an emphasis on M./miR96//foxO1 signaling cascades, as a novel pathway of melatonin signaling in adenocarcinoma to diminish cancer cell growth, survival and metastasis.

Effect of a dietary and exercise intervention in women with overweight and obesity undergoing fertility treatments: protocol for a randomized controlled trial

BACKGROUND

Distinct molecular, inflammatory, and metabolic signatures are present in oocytes and follicular fluid derived from women with obesity when compared to those derived from normal weight women, which suggest existing signals that may program future offspring for metabolic diseases. This study aims to assess the feasibility and efficacy of a peri-conception nutrition and exercise intervention on mitigating obesity-associated changes in oocyte gene expression profiles and follicular fluid metabolites.

METHODS

This single blinded randomized control trial will include 120 women with a BMI of 25-45 kg/m², ≥21 years of age, and undergoing in vitro fertilization (IVF) treatments. Participants will be randomized to standard of care (N = 60) or an intervention group (N = 60) in a block design by polycystic ovary syndrome status. The intervention will combine a dietary component (Mediterranean meal plan) with exercise prescription following the Physical Activity Guidelines for Americans. Participants will be assessed pre- and post-intervention. The standard of care group will be offered to join the intervention group if the IVF treatments are unsuccessful as a cross over design. Recruitment is anticipated to start in July of 2021. Primary outcomes will include single oocyte gene expression profiles and follicular fluid metabolites. Mann-Whitney U nonparametric tests will be used to assess potential differences for each stratum. Follicular fluid and serum metabolites will be analyzed using a one-factor Analysis of Covariance (ANCOVA) at four levels, pair-wise comparisons using Tukey-Kramer post-hoc tests will be used to identify groups whose means differ significantly while retaining the family-wise error rate at 5%. When the design is balanced, two-way Analysis of Variance (ANOVA), or non-parametric Friedman test will be used in data analysis. Additionally, general linear models and ANCOVA may be used to control for covariates. Significance will be set at p < 0.05. Findings will be disseminated via peer-reviewed manuscripts and presentations at scientific conferences.

DISCUSSION

This study will provide novel data and key information on the impact of a dietary and exercise intervention on oocyte gene expression and follicular fluid content. Results will demonstrate the potential of such intervention in mitigating obesity-induced changes in oocyte gene expression and follicular fluid metabolites.

TRIAL REGISTRATION

ClinicalTrials.gov ( NCT04273048 ): submitted November 13, 2019; posted February 17, 2020.

Melatonin promotes in vitro maturation of vitrified-warmed mouse GV oocytes potentially by modulating MAD2 protein expression of SAC component through MTRs

Previous studies have shown that melatonin (MT) can ameliorate vitrification-inflicted damage in mouse germinal vesicle (GV) oocytes, however, the key mechanistic basis of this improvement still remains poorly understood. This study was conducted to investigate whether MT can improve in vitro developmental potential of vitrified-warmed GV oocytes through its receptors. The fresh oocytes were randomly divided into four groups: untreated (control group, F), vitrified by open-pulled straw method (vitrification group, V), vitrification group with 100 nmol/L MT supplementation (vitrification + MT group, VM), and with 100 nmol/L MT plus 100 nmol/L luzindole administration (vitrification + MT + luzindole group, VML) or with 50 nmol/L ramelteon addition (vitrification + ramelteon group; VR). After warming, oocytes were cultured in vitro, and MT receptors (MTRs), MAD2 (mitotic arrest deficient 2), Securin and CyclinB1 protein levels and spindle morphology were evaluated. The ratio of oocytes developed to the metaphase I (MI) and metaphase II (MII) stages was also assessed. The results showed that after vitrification-warming, the in vitro maturation rate of GV oocytes was significantly lower compared to the control (F) group. Vitrification also significantly impaired the spindle morphology, decreased the protein level of MTRs and Securin, and decreased MAD2 levels in MI oocytes. However, when MT or ramelteon (MTRs agonist) were added (group wise) to warming and maturation media, the maturation rate of GV oocytes was significantly increased, the normal proportion of the spindle morphology increased, and the expression level of MAD2 increased in their resulting MI oocytes compared to the vitrification group. However, following addition of both MT and ramelteon, the maturation rate of GV oocyte showed no significant difference between VML and vitrification groups. The spindle morphology and MAD2 levels in MI oocytes were comparable to the vitrification group but differed significantly from the VM group. Taken together, finding of the present study shows that MT (100 nmol/L) can ameliorate the in vitro maturation of vitrified-warmed mouse GV oocytes, potentially by improving the spindle morphology, modulating MAD2 protein level and promoting the development of MI stage oocytes through MTRs.

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).

Melatonin Represses Mitophagy to Protect Mouse Granulosa Cells from Oxidative Damage

Various environmental stimuli, including oxidative stress, could lead to granulosa cell (GC) death through mitophagy. Recently, it was reported that melatonin (MEL) has a significant effect on GC survival during oxidative damage. Here, we found that MEL inhibited oxidative stress-induced mitophagy to promote GC survival. The loss of cell viability upon H₂O₂ exposure was significantly restored after MEL treatment. Concomitantly, MEL inhibited the activation of mitophagy during oxidative stress. Notably, blocking mitophagy repressed GC death caused by oxidative stress. However, MEL cannot further restore viability of cells treated with mitophagy inhibitor. Moreover, PTEN-induced putative kinase 1 (PINK1), a mitochondrial serine/threonine-protein kinase, was inhibited by MEL during oxidative stress. As a result, the E3 ligase Parkin failed to translocate to mitochondria, leading to impaired mitochondria clearance. Using RNAi to knock down PINK1 expression, we further verified the role of the MEL-PINK1-Parkin (MPP) pathway in maintaining GC survival by suppressing mitophagy. Our findings not only clarify the protective mechanisms of MEL against oxidative damage in GCs, but also extend the understanding about how circadian rhythms might influence follicles development in the ovary. These findings reveal a new mechanism of melatonin in defense against oxidative damage to GCs by repressing mitophagy, which may be a potential therapeutic target for anovulatory disorders.

Antioxidant and cytoprotective effects of Nigella sativa L. seeds on the testis of monosodium glutamate challenged rats

Monosodium glutamate (MSG) is one of the most widely spread food additives that might cause male infertility. However, Nigella sativa L. seeds (NSS) could provide a solution. This study was designed to investigate the potential effects of NSS on rats ingesting MSG. To achieve this aim, adult male albino rats were randomly equally assigned into three groups for 21 days: control group received no treatment, MSG group received MSG as 30 g/kg feed, and MSG + NSS group received MSG as 30 g/kg and NSS as 30 g/kg feed. Testis histomorphometry showed marked deterioration by MSG as atrophic seminiferous tubules with degeneration of their lining cells, damaged Leydig cells and decreased germ cells number. Periodic Acid Schiff stain indicated irregular interrupted basement membranes. Glutathione reductase, superoxide dismutase 2 (SOD2), and caspase-3 immuno-expressions increased in testicular cells. Testosterone levels were significantly decreased in MSG challenged rats along with significant increase in luteinizing hormone levels, whereas NSS normalized this hormonal profile. MSG exposure also caused significantly increased lipid peroxides (LPO), glutathione-S-transferase, and total antioxidant capacity (TAC) whereas nitric oxide and SOD2 were significantly decreased. NSS succeeded in rebalance LPO and TAC and ameliorated the histoarchitectural disturbances. NSS mitigated MSG-induced testicular impairment by its antioxidant and cytoprotective activities.

Dihydrotestosterone regulates oestrogen secretion, oestrogen receptor expression, and apoptosis in granulosa cells during antral follicle development

Dihydrotestosterone (DHT) is involved in the development of preantral follicles. However, the effect of DHT on the development of antral follicles has yet to be fully investigated. Herein, we used enzyme-linked immunosorbent assays, immunofluorescence assays, quantitative real time-polymerase chain reaction, immunohistochemical staining, and western blotting to investigate the effect of DHT on antral follicle development. First, we detected the concentration of DHT and the expression of the androgen receptor (AR) in different antral follicles. Second, multiple DHT concentration (10^-10-10^-7 M) were added to granulosa cells cultured in vitro to examine the influence of DHT on AR expression. Third, to study changes in the expression of oestrogen (E2) synthase and receptors during the development of antral follicles, we divided them according to their diameters into small (≤ 2 mm), medium (2-5 mm), and large (≥ 5 mm) groups. Fourth, we added DHT (10^-8 M) and flutamide (Flu, 10^-7 M) to granulosa cells to determine whether DHT regulates the expression of cytochrome P450 aromatase (CYP19A1) and the associated receptors through the AR pathway. Fifth, we tested the effect of DHT and Flu on the expression of apoptotic genes and proteins in granulosa cells. We found that AR was expressed in sheep antral follicle granulosa cells and was regulated by DHT. During antral follicle development, the concentration of E2 and the expression of CYP19A1 and E2 receptors significantly increased in granulosa cells. DHT influenced this increase, at least partially, through the AR. Moreover, DHT regulated the expression of apoptotic genes and proteins through the AR. Our study expands our knowledge on the regulatory mechanism of DHT in antral follicle development and guides further research on the androgen regulation of ovarian function.

Central and peripheral actions of melatonin on reproduction in seasonal and continuous breeding mammals

Under field conditions, especially for mammals that inhabit high latitudes, the regulation of seasonal breeding activity to ensure delivery of the young at the time most conducive to their survival is essential. This is most frequently accomplished by the annual reproductive cycle being linked to seasonal photoperiod changes which determine the nocturnal duration of the pineal melatonin signal. Mating can occur during any season that ensures spring/early summer delivery of the offspring. Thus, the season of mating is determined by the duration of pregnancy. The precise hormonal control of the annual cycle of reproduction by melatonin is accomplished at the level of the hypothalamo-pituitary axis which, in turn, determines the physiological state of the gonad and adnexa due to the regulation of pituitary gonadotrophin release. Many species are continuous rather than seasonal breeders. In these species, melatonin has a minor hormonal influence on the central regulation of reproduction but, nevertheless, its antioxidant functions at the level of the gonads support optimal reproductive physiology. Possibly like all cells, those in the ovary, e.g., granulosa cells and oocytes (less is known about melatonin synthesis by the testes or spermatogenic cells), synthesize melatonin which is used locally to combat free radicals and reactive nitrogen species which would otherwise cause oxidative/nitrosative stress to these critically important cells. Oxidative damage to the oocyte, zygote, blastocyst, etc., results in an abnormal fetus which is either sloughed or gives rise to an unhealthy offspring. The importance of the protection of the gametes (both oocytes and sperm) from oxidative molecular mutilation cannot be overstated. Fortunately, as a highly effective free radical scavenger and indirect antioxidant (by upregulating antioxidant enzyme), locally-produced melatonin is in the optimal location to protect the reproductive system from such damage.