Zearalenone modulates the function of goat endometrial cells via the mitochondrial quality control system.

Zearalenone (ZEN) is a mycotoxin known for its estrogen-like effects, which can disrupt the normal physiological function of endometrial cells and potentially lead to abortion in female animals. However, the precise mechanism by which ZEN regulates endometrial function remains unclear. In this study, we found that the binding receptor estrogen receptors for ZEN is extensively expressed across various segments of the uterus and within endometrial cells, and a certain concentration of ZEN treatment reduced the proliferation capacity of goat endometrial epithelial cells (EECs) and endometrial stromal cells (ESCs). Meanwhile, cell cycle analysis revealed that ZEN treatment leaded to cell cycle arrest in goat EECs and ESCs. To explore the underlying mechanism, we investigated the mitochondrial quality control systems and observed that ZEN triggered excessive mitochondrial fission and disturbed the balance of mitochondrial fusion-fission dynamics, impaired mitochondrial biogenesis, increased mitochondrial unfolded protein response and mitophagy in goat EECs and ESCs. Additionally, ZEN treatment reduced the activities of mitochondrial respiratory chain complexes, heightened the production of hydrogen peroxide and reactive oxygen species, and caused cellular oxidative stress and mitochondrial dysfunction. These results suggest that ZEN has adverse effects on goat endometrium cells by disrupting the mitochondrial quality control system and affecting cell cycle and proliferation. Understanding the underlying molecular pathways involved in ZEN-induced mitochondrial dysfunction and its consequences on cell function will provide critical insights into the reproductive toxicity of ZEN and contribute to safeguarding the health and wellbeing of animals and humans exposed to this mycotoxin.

Decreased AMPK/SIRT1/PDK4 induced by androgen excess inhibits human endometrial stromal cell decidualization in PCOS.

Polycystic ovary syndrome (PCOS) is a complex common endocrine disorder affecting women of reproductive age. Ovulatory dysfunction is recognized as a primary infertile factor, however, even when ovulation is medically induced and restored, PCOS patients continue to experience reduced cumulative pregnancy rates and a higher spontaneous miscarriage rate. Hyperandrogenism, a hallmark feature of PCOS, affects ovarian folliculogenesis, endometrial receptivity, and the establishment and maintenance of pregnancy. Decidualization denotes the transformation that the stromal compart of the endometrium must undergo to accommodate pregnancy, driven by the rising progesterone levels and local cAMP production. However, studies on the impact of hyperandrogenism on decidualization are limited. In this study, we observed that primary endometrial stromal cells from women with PCOS exhibit abnormal responses to progesterone during in vitro decidualization. A high concentration of testosterone inhibits human endometrial stromal cells (HESCs) decidualization. RNA-Seq analysis demonstrated that pyruvate dehydrogenase kinase 4 (PDK4) expression was significantly lower in the endometrium of PCOS patients with hyperandrogenism compared to those without hyperandrogenism. We also characterized that the expression of PDK4 is elevated in the endometrium stroma at the mid-secretory phase. Artificial decidualization could enhance PDK4 expression, while downregulation of PDK4 leads to abnormal decidualization both in vivo and in vitro. Mechanistically, testosterone excess inhibits IGFBP1 and PRL expression, followed by phosphorylating of AMPK that stimulates PDK4 expression. Based on co-immunoprecipitation analysis, we observed an interaction between SIRT1 and PDK4, promoting glycolysis to facilitate decidualization. Restrain of AR activation resumes the AMPK/SIRT1/PDK4 pathway suppressed by testosterone excess, indicating that testosterone primarily acts on decidualization through AR stimulation. Androgen excess in the endometrium inhibits decidualization by disrupting the AMPK/SIRT1/PDK4 signaling pathway. These data demonstrate the critical roles of endometrial PDK4 in regulating decidualization and provide valuable information for understanding the underlying mechanism during decidualization.

Lysosome dynamics during human endometrial stromal cells decidualization: effect of para-nonylphenol.

During the process of decidualization, the stromal cells of the endometrium change dynamically to create a favorable environment for embryo implantation. Lysosome activity has often been associated with physiological changes in the endometrium during the preimplantation period and early pregnancy. In this study, the effect of para-nonylphenol (p-NP), an endocrine disruptor, on human immortalized endometrial stromal cells (tHESCs) was investigated. After exposure to p-NP (1 nM and 1 pM), the cells were examined for the decidualization markers connexin-43, insulin like growth factor binding protein 1 (IGFBP1), and prolactin. In addition, the effect of p-NP on lysosome biogenesis and exocytosis was investigated by examining the expression and localization of the transcription factor EB (TFEB) and that of the lysosomal-associated membrane protein 1 (LAMP-1). Finally, we evaluated the effect of p-NP on extracellular matrix (ECM) remodeling using a fibronectin assay. Our results showed that p-NP reduced the expression of prolactin protein, increased the nuclear localization of TFEB, and induced the increase and translocation of the lysosomal protein LAMP-1 to the membrane of tHESCs. The data indicate an impairment of decidualization and suggest an increase in lysosomal biogenesis and exocytosis, which is supported by the higher release of active cathepsin D by tHESCs. Given the importance of cathepsins in the processing and degradation of the ECM during trophoblast invasiveness and migration into the decidua, our results appear to be clear evidence of the negative effects of p-NP on endometrial processes that are fundamental to reproductive success and the establishment of pregnancy.NEW & NOTEWORTHY Endocrine disruptors, such as para-nonylphenol, affect the decidualization of human endometrial stromal cells with an impact on decidualization itself, lysosome biogenesis and exocytosis, and extracellular matrix remodeling. All these alterations may negatively impact embryo implantation with the success of reproduction and the establishment of pregnancy.

CTRP6 alleviates endometrial fibrosis by regulating Smad3 pathway in intrauterine adhesion†.

Intrauterine adhesion (IUA) is manifestations of endometrial fibrosis and excessive extracellular matrix deposition. C1q/tumor necrosis factor-related protein-6 (CTRP6) is a newly identified adiponectin paralog which has been reported to modulate the fibrosis process of several diseases; however, the endometrial fibrosis function of CTRP6 remains unknown. Our study aimed to assess the role of CTRP6 in endometrial fibrosis and further explore the underlying mechanism. Here, we found that the expression of CTRP6 was downregulated in the endometrial tissues of IUA. In vitro experiments demonstrated the reduced level of CTRP6 in facilitated transforming growth factor-ß1 (TGF-ß1)-induced human endometrial stromal cells (HESCs). In addition, CTRP6 inhibited the expression of α-smooth muscle actin (α-SMA) and collagen I in TGF-ß1-treated HESCs. Mechanistically, CTRP6 activated the AMP-activated protein kinase (AMPK) and protein kinase B (AKT) pathway in HESCs, and AMPK inhibitor (AraA) or PI3K inhibitor (LY294002) pretreatment abolished the protective effect of CTRP6 on TGF-ß1-induced fibrosis. CTRP6 markedly decreased TGF-ß1-induced Smad3 phosphorylation and nuclear translocation, and AMPK or AKT inhibition reversed these effects. Notably, CTRP6-overexpressing treatment alleviated the fibrosis of endometrium in vivo. Therefore, CTRP6 ameliorates endometrial fibrosis, among which AMPK and AKT are essential for the anti-fibrotic effect of CTRP6 via the Smad3 pathway. Taken together, CTRP6 may be a potential therapeutic target for the treatment of intrauterine adhesion.

Interferon-tau infusion into the ovine corpus luteum delays luteolysis†.

Conceptus-derived interferon-tau (IFNT) initiates maternal recognition of pregnancy in ewes by paracrine actions on the endometrium and endocrine action on the corpus luteum (CL). To examine the effect of IFNT on the CL without inducing IFN-stimulated genes (ISGs) in the endometrium, recombinant ovine IFNT (roIFNT) or bovine serum albumin was delivered directly into CLs via osmotic pumps at a rate of 10, 50, or 100 ng/h from days 9 to 12 of the estrous cycle. Endometrial and CL samples were collected on day 12. 50 ng/h of roIFNT induced ISG15 in the CL on day 12 without affecting endometrial ISG15 concentrations. In a second experiment, roIFNT (50 ng/h) was infused into the CL from days 10 to 17 of the estrous cycle and serum samples were collected daily. Serum progesterone concentrations were significantly higher from days 15 to 17 in roIFNT-infused ewes compared to controls. Levels of LHCGR, STAR, CYP11A1, HSL, OPA1, and protein kinase A mRNA and proteins were higher in the roIFNT-infused CLs compared to the controls. Levels of ISG15 and MX1 mRNA increased in the CLs of roIFNT-infused ewes but not in the endometrium. Endometrial ESR1 mRNA and protein concentrations were higher in the controls compared to roIFNT-infused ewes. In conclusion, intra-luteal delivery of roIFNT induced ISGs, stabilized steroidogenesis in the CL, and delayed luteolysis without inducing endometrial IFN-stimulated genes. Inhibition of ESR1 in the endometrium of roIFNT-infused ewes was observed suggesting that direct delivery of IFNT to the CL has an additional anti-luteolytic effect on the endometrium.

In vitro reminiscence: uterine programming in vivo affects respective luminal epithelial cells function in vitro†.

In cattle, the endometrium during diestrus and early pregnancy displays cellular responses that are consequences of prior, transient stimuli. Goal was to establish a model to study cellular memory in the endometrium. The hypothesis is that stimuli given to endometrium in vivo are retained as a cellular memory that remains after bovine uterine epithelial cells (BUECs) are isolated, cultured, and further stimulated in vitro. Objectives were to measure BUEC proliferation/migration and responsiveness to recombinant bovine Interferon-tau (rbIFNT) in vitro: among cows that showed estrus (experiment 1 [Exp1]), cows that became or not pregnant to artificial insemination (Exp2), cows that received or not supplemental progesterone (P4; Exp3) and cows that received or not a COX-1/2 inhibitor (Exp4). Only cows that displayed estrus were included in studies. For all experiments endometrial cytology was collected 4 days after estrus, BUECs were cultured, propagated, and submitted to rbIFNT treatment and an in vitro scratch assay. In Exp1, different cows spontaneously grouped according to proliferative/migratory capacity and responsiveness to rbIFNT of their respective BUECs. In Exp2, BUECs from pregnant cows showed greater rbIFNT responsiveness and cellular proliferation. In Exp3, BUECs from cows supplemented with P4 presented inhibited proliferation and increased expression of RSAD2. In Exp4, Flunixin Meglumine modified rbIFNT responsiveness of BUECs in an IFN-signaling pathway-specific manner. In conclusion, physiological and pharmacological stimuli received by the endometrium in vivo were retained as cellular memory in BUECs, persisted in culture, and changed BUEC proliferation/migration and responsiveness to rbIFNT, which are characteristics associated with fertility in cattle.

Protective effects of engineered Lactobacillus crispatus strains expressing G-CSF on thin endometrium of mice.

STUDY QUESTION: Does recombinant Lactobacillus expressing granulocyte colony-stimulating factor (G-CSF) have a better protective effect than the current treatment of thin endometrium (TE)? SUMMARY ANSWER: This study suggested that the intrauterine injection of Lactobacillus crispastus (L. crispastus)-pPG612-G-CSF has a positive effect on preventing TE induced by 95% alcohol in mice. WHAT IS KNOWN ALREADY: TE has a negative impact on the success rate of ART in patients, and is usually caused by intrauterine surgery, endometrial infection, or hormone drugs. Exogenous G-CSF can promote endometrial vascular remodelling and increase endometrial receptivity and the embryo implantation rate. Moreover, Lactobacillus plays a crucial role in maintaining and regulating the local microecological balance of the reproductive tract, and it could be a delivery carrier of the endometrial repair drug G-CSF. STUDY DESIGN, SIZE, DURATION: We constructed engineered L. crispastus strains expressing G-CSF. The mice were divided into five groups: (i) Control group (C, n = 28), uteri were treated with preheated saline solution via intrauterine injection on the third and sixth day of oestrus; (ii) Model group (M, n = 35), where uteri were treated with 95% alcohol on the third day of oestrus and preheated saline solution on the sixth day of oestrus via intrauterine injection; (iii) L. crispatus-pPG612-treatment group (L, n = 45), where uteri were treated with 95% alcohol on the third day of oestrus and 0.1 ml × 108 CFU/ml L. crispatus-pPG612 on the sixth day of oestrus via intrauterine injection; (iv) L. crispatus-pPG612-treatment group (LG, n = 45), where uteri were treated with 95% alcohol on the third day of oestrus and 0.1 ml × 108 CFU/ml L. crispatus-pPG612-G-CSF on the sixth day of oestrus via intrauterine injection; (v) G-CSF-treatment group (G, n = 52), where uteri were treated with 95% alcohol on the third day of oestrus and 30 µg/kg G-CSF on the sixth day of oestrus via intrauterine injection. Then, we compared the effects of L. crispastus, L. crispatus-pPG612-G-CSF and G-CSF on endometrial thickness, angiogenesis, fibrosis, and inflammation in the TE mouse. PARTICIPANTS/MATERIALS, SETTING, METHODS: We collected uterine tissues for haematoxylin-eosin staining, immunohistochemical staining, Western blot and RT-PCR, as well as serum for ELISA and uterine flushing solution for high-throughput sequencing. MAIN RESULTS AND THE ROLE OF CHANCE: Compared with those in the M group (the mice of the group were intrauterine injected 95% alcohol and treated with saline solution), the L. crispatus-pPG612-G-CSF strain increased the thickness of the endometrium (P < 0.001) and the number of blood vessels and glands (both P < 0.001), enhanced the expression of cytokeratin 19 (CK19) (P < 0.001), vimentin (Vim) (P < 0.001), vascular endothelial growth factor-A (P < 0.001), and CD34 (P < 0.001), and decreased fibrosis levels (P = 0.004). In addition, the high-throughput sequencing results indicated that the L. crispatus-pPG612-G-CSF strain could decrease the abundance of Pseudomonas (P = 0.044) and Actinomyces spp. (P = 0.094) in TE mice and increased the average number of embryos (P = 0.036). Finally, the L. crispatus-pPG612-G-CSF strain was preliminarily confirmed to activate the phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) signalling pathway and enhance the mRNA expression of hypoxia-inducible factor-1α (P < 0.001), vascular endometrial growth factor (P = 0.003), and endothelial cell nitric oxide synthase (P = 0.003) in mouse uterine tissue. LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: Therapy with the L. crispatus-pPG612-G-CSF strain has tremendous potential to accelerate the reparative processes of TE. However, we have reported only the expression of genes and proteins related to the PI3K/AKT pathway, and numerous other mechanisms may also be involved in the restoration of the endometrium by L. crispatus-pPG612-G-CSF. WIDER IMPLICATIONS OF THE FINDINGS: The results from the study provide new ideas and suggest new methods for TE treatment. STUDY FUNDING/COMPETING INTEREST(S): This work was financially supported by the Project of Science and Technology Development Plan of Jilin Province (grant number 20210101232JC), the Science and Technology Plan Item of Jilin Provincial Education Department (grant number JT53101022010), and the Doctoral Research Start-up Fund of Jilin Medical University (grant numbers JYBS2021014LK and 2022JYBS006KJ). The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as potential conflicts of interest.

Progesterone levels do not differ between patients with or without endometriosis/adenomyosis both in those who conceive after hormone replacement therapy-frozen embryo transfer cycles and those who do not.

STUDY QUESTION: Do women with endometriosis who achieve a live birth (LB) after HRT-frozen embryo transfer (HRT-FET) have different progesterone levels on the day of transfer compared to unaffected women? SUMMARY ANSWER: In women achieving a LB after HRT-FET, serum progesterone levels on the day of the transfer did not differ between patients with endometriosis and unaffected patients. WHAT IS KNOWN ALREADY: In HRT-FET, several studies have highlighted the correlation between serum progesterone levels at the time of FET and LB rates. In the pathophysiology of endometriosis, progesterone resistance is typically described in the eutopic endometrium. This has led to the hypothesis that women with endometriosis may require higher progesterone levels to achieve a LB, especially in HRT-FET cycles without a corpus luteum. STUDY DESIGN, SIZE, DURATION: We conducted an observational cohort study at the university-based reproductive medicine center of our institution, focusing on women who underwent a single autologous frozen blastocyst transfer after HRT using exogenous estradiol and micronized vaginal progesterone for endometrial preparation between January 2019 and December 2021. Women were included only once during the study period. Serum progesterone levels were measured on the morning of the FET by a single laboratory. PARTICIPANTS/MATERIALS, SETTING, METHODS: Patients were divided into groups based on whether they had endometriosis or not and whether they achieved a LB. The diagnosis of endometriosis was based on published imaging criteria (transvaginal sonography/magnetic resonance imaging) and/or confirmed histology. The primary outcome was progesterone levels on the day of the HRT-FET leading to a LB in patients with endometriosis compared to unaffected women. Subgroup analyses were performed based on the presence of deep infiltrating endometriosis or adenomyosis. MAIN RESULTS AND THE ROLE OF CHANCE: A total of 1784 patients were included. The mean age of the women was 35.1 ± 4.1 (SD) years. Five hundred and sixty women had endometriosis, while 1224 did not. About 179/560 (32.0%) with endometriosis and 381/1224 (31.2%) without endometriosis achieved a LB. Among women who achieved a LB after HRT-FET, there was no significant difference in the mean progesterone level on the day of the HRT-FET between those with endometriosis and those without (13.6 ± 4.3 ng/ml vs 13.2 ± 4.4 ng/ml, respectively; P = 0.302). In the subgroup of women with deep infiltrating endometriosis (n = 142) and adenomyosis (n = 100), the mean progesterone level was 13.1 ± 4.1 ng/ml and 12.6 ± 3.7 ng/ml, respectively, with no significant difference compared to endometriosis-free patients. After adjusting for BMI, parity, duration of infertility, tobacco use, and geographic origin, neither the presence of endometriosis (coefficient 0.38; 95% CI: -0.63 to 1.40; P = 0.457) nor the presence of adenomyosis (coefficient 0.97; 95% CI: -0.24 to 2.19; P = 0.114) was associated with the progesterone level on the day of HRT-FET. Among women who did not conceive, there was no significant difference in the mean progesterone level on the day of the HRT-FET between those with endometriosis and those without (P = 0.709). LIMITATIONS, REASONS FOR CAUTION: The primary limitation of our study is associated with its observational design. Extrapolating our results to other laboratories or different routes and/or dosages of administering progesterone also requires validation. WIDER IMPLICATIONS OF THE FINDINGS: This study shows that patients diagnosed with endometriosis do not require higher progesterone levels on the day of a frozen blastocyst transfer to achieve a LB in hormonal replacement therapy cycles. STUDY FUNDING/COMPETING INTEREST(S): None declared. TRIAL REGISTRATION NUMBER: N/A.

A multicentre, randomized, double-blind, placebo-controlled trial of topical oestradiol gel for endometrial regeneration after induced abortion.

STUDY QUESTION: Is topical oestradiol gel effective in promoting endometrial regeneration after a surgical abortion? SUMMARY ANSWER: Topical oestradiol gel is effective in promoting endometrial regeneration after a surgical abortion with few side-effects. WHAT IS KNOWN ALREADY: Oestrogen is effective in promoting endometrial regeneration. Transdermal oestrogen has been widely used in clinical practice for endometrial regeneration after induced abortion, but high-level evidence is limited. STUDY DESIGN, SIZE, DURATION: We conducted a multicentre, superiority, randomized, double-blind, placebo-controlled trial. Between 9 March 2022 and 21 February 2023, 200 women were assigned in a 1:1 ratio to receive either oestradiol gel (treatment) and or oestradiol gel simulant (control) for 28 days. The participants were scheduled to have their endometrial thickness (mm) measured by ultrasonographic scan at 21-23 days post-abortion. The trial was blinded for participants, investigators, medical staff, and statistical analysts until final unblinding. PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants were women undergoing induced abortion within 10 weeks of gestation. A total of 200 participants were enrolled, with 100 in each group. Eighty-eight (88%) in the treatment group and 82 (82%) in the control group completed the study as per the protocol and were included in the per-protocol set (PPS). The intent-to-treat (ITT) analysis included all participants randomized to the study groups and used inverse probability weighting to account for loss to follow-up. MAIN RESULTS AND THE ROLE OF CHANCE: The ITT analysis showed revealed significantly greater endometrial thickness in the treatment group (mean 8.1 ± 2.5 mm) compared to the control group (mean 6.9 ± 2.1 mm) 21-23 days postabortion (mean difference 1.2 mm, 95% CI 0.7 to 1.9; P < 0.001). The median time to menstrual return was shorter in the treatment group (34 days, inter-quartile range [IQR] 30-38) than in the control group (35 days, IQR 32-42), with a difference of -1 day (95% CI -2.3 to -0.9; P = 0.036). No differences were observed in the timing or volume of bleeding in the first post-abortion cycle. The PPS analysis mirrored the ITT findings. Adverse events were minimal (6% versus 8%), and the blood profile, liver, kidney and coagulation test results were comparable between groups (all P > 0.05). LIMITATIONS, REASONS FOR CAUTION: Loss to follow-up was 11% in the treatment group and 15% of controls, with no significant difference (P > 0.05). Inconsistencies in the timing of the ultrasonographic scans may have affected the accuracy of endometrial thickness measurements. WIDER IMPLICATIONS OF THE FINDINGS: Our findings suggest that topical oestrogen supplementation immediately after abortion within the first 10 weeks of gestation improves endometrial regeneration and growth, thereby potentially increasing the chances of a successful subsequent pregnancy. Clinical application of these findings may improve endometrial health management practices and provide a perspective on fertility treatment and women's reproductive health. STUDY FUNDING/COMPETING INTEREST(S): This study was supported by a grant (FW-HKKT2021111501900) from Jianmin Pharmaceutical Group Co., Ltd (JMPG), Wuhan, Hubei, China. Both the oestradiol gel and the simulant were provided by JMPG. The funding source had no role in the study. X.Y.L. reports JMPG grant funding paid to their institutions. All other authors declare no competing interests. TRIAL REGISTRATION NUMBER: CHiCTR2100053565. TRIAL REGISTRATION DATE: 24 November 2021. DATE OF FIRST PATIENT'S ENROLMENT: 9 March 2022.

Exogenous melatonin ameliorates embryo-maternal cross-talk in early pregnancy in sheep.

In brief: Melatonin plays a crucial role in enhancing reproductive performance in small ruminants. This paper reveals the effects of exogenous melatonin on the placental and endometrial rearrangement in early pregnancy in sheep. Abstract: Early pregnancy losses cause 25% of pregnancy failures in small ruminants because of asynchrony between conceptus and uterine signals. In this context, melatonin plays a crucial role in sheep reproductive dynamics, but little is known about its effects during the peri-implantation period. We hypothesized that melatonin supports embryo implantation by modulating the uterine microenvironment. This study aimed to assess the effects of exogenous melatonin on the endometrial and early placental rearrangement. Ten multiparous ewes either did (MEL, n = 5) or did not (CTR, n = 5) receive a subcutaneous melatonin implant (18 mg) 50 days before a synchronized mating. On day 21 of pregnancy, the sheep were euthanized. MEL ewes exhibited a higher prolificity rate (2.8 vs 2.0 embryos/ewe) and plasma progesterone levels (3.84 vs 2.96 ng/mL, P < 0.05) than did CTR ewes. Groups did not differ significantly in embryo crown-rump length. MEL placentas had significantly (P < 0.001) more binucleated trophoblast cells in the chorion region, and ovine placental lactogen expression was significantly (P < 0.05) more strongly upregulated than in CTR. Exogenous melatonin increased significantly (P < 0.05) gene expression of angiogenic factors (VEGFA, VEGFR1, IGF1R), IFNAR2, and PR in the caruncular endometrium. Expression of the MT2 receptor in the endometrium and placenta was significantly (P < 0.05) higher in the MEL group. These results indicate that melatonin implants acted differentially on uterine and placental rearrangement. Melatonin increases differentiation in the placenta and induces changes that could promote vessel maturation in the endometrium, suggesting that it enhances the uterine microenvironment in the early stage of pregnancy in sheep.

Membrane progesterone receptors mediate progesterone-stimulated glycogenolysis in the bovine uterine epithelium.

In livestock, the amount of glucose needed by the endometrium and embryo increases during early pregnancy. Yet, how glucose concentrations in the endometrium are regulated remains unclear. The bovine uterine epithelium can store glucose as glycogen, and glycogen content decreases in the luteal phase. Our objective was to elucidate the role of progesterone in glycogen breakdown in immortalized bovine uterine epithelial (BUTE) cells. After 48 h of treatment, progesterone decreased glycogen abundance in BUTE cells (P < 0.001) but did not alter glycogen phosphorylase levels. RU486, a nuclear progesterone receptor (nPR; part of the PAQR family) antagonist, did not block progesterone's effect, suggesting that progesterone acted through membrane progesterone receptors (mPRs). RT-PCR confirmed that BUTE cells express all five mPRs, and immunohistochemistry showed that the bovine uterine epithelium expresses mPRs in vivo. An mPRα agonist (Org OD 02-0) reduced glycogen abundance in BUTE cells (P < 0.001). Progesterone nor Org OD 02-0 affected cAMP concentrations. Progesterone increased phosphorylated AMP-activated protein kinase (pAMPK) levels (P < 0.001), indicating that progesterone increases intracellular AMP concentrations. However, AMPK did not mediate the effect of progesterone. AMP allosterically activates glycogen phosphorylase, and D942 (which increases intracellular AMP concentrations) decreased glycogen abundance in BUTE cells. A glycogen phosphorylase inhibitor partially blocked the effect of progesterone (P < 0.05). Progesterone and Org OD 02-0 had similar effects in Ishikawa cells (P < 0.01), a human cell line that lacks nPRs. In conclusion, progesterone stimulates glycogen breakdown in the uterine epithelium via mPR/AMP signaling. Glucose released from glycogen could support embryonic development or be metabolized by the uterine epithelium.

Asiaticoside ameliorates uterine injury induced by zearalenone in mice by reversing endometrial barrier disruption, oxidative stress and apoptosis.

Zearalenone (ZEA) is a mycotoxin produced by Fusarium fungi that has been shown to have adverse effects on human and animal health, particularly on the fertility of females. As a saponin derived from the medicinal plant Centella asiatica, asiaticoside (AS) has multiple bioactivities. This study aimed to investigate the protective effects of AS on ZEA-induced uterine injury and the underlying mechanism. In the present study, we demonstrated that AS could rescue ZEA-induced uterine histopathological damage and modulate the secretion of sex hormones, including progesterone (P4), luteinizing hormone (LH), and estradiol (E2), in ZEA-treated mice. Moreover, AS alleviated ZEA-induced damage to endometrial barrier function by upregulating the expression of tight junction proteins (ZO-1, occludin, and claudin-3). Further mechanistic investigations indicated that ZEA reduces the antioxidant capacity of uterine tissues, whereas AS improves the antioxidant capacity through activating the Nrf2 signaling pathway. Most notably, the protective effect of AS was blocked in Nrf2 gene knockout (Nrf2-/-) mice. Moreover, the p38/ERK MAPK pathway has been implicated in regulating ZEA toxicity and the beneficial effect of AS. Additionally, an Nrf2 inhibitor (ML385) weaken the suppressive effect of AS on the oxidative stress and MAPK pathway. AS also inhibits ZEA-induced apoptosis in uterine tissues via the PI3K/Akt signaling pathway. However, when the PI3K small molecule inhibitor LY294002 was co-administered, the ability of AS to suppress the expression of apoptosis-related proteins and inhibit ZEA-induced apoptosis decreased. Collectively, these findings reveal the involvement of multiple pathways and targets in the protective effect of AS against ZEA-induced uterine injury, providing a new perspective for the application of AS and the development of a ZEA antidote.

Quercetin enhances decidualization through AKT-ERK-p53 signaling and supports a role for senescence in endometriosis.

BACKGROUND: Patients with endometriosis suffer with chronic pelvic pain and infertility, and from the lack of pharmacologic therapies that consistently halt disease progression. Differences in the endometrium of patients with endometriosis vs. unaffected controls are well-documented. Specifically, shed endometrial tissues (delivered to the pelvic cavity via retrograde menstruation) reveal that a subset of stromal cells exhibiting pro-inflammatory, pro-fibrotic, and pro-senescence-like phenotypes is enhanced in endometriosis patients compared to controls. Additionally, cultured biopsy-derived endometrial stromal cells from endometriosis patients exhibit impaired decidualization, a defined differentiation process required for human embryo implantation and pregnancy. Quercetin, a senolytic agent, shows therapeutic potential for pulmonary fibrosis, a disorder attributed to senescent pulmonary fibroblasts. In rodent models of endometriosis, quercetin shows promise, and quercetin improves decidualization in vitro. However, the exact mechanisms are not completely understood. Therefore, we investigated the effects of quercetin on menstrual effluent-derived endometrial stromal cells from endometriosis patients and unaffected controls to define the signaling pathways underlying quercetin's effects on endometrial stromal cells. METHODS: Menstrual effluent-derived endometrial stromal cells were collected and cultured from unaffected controls and endometriosis patients and then, low passage cells were treated with quercetin (25 µM) under basal or standard decidualization conditions. Decidualization responses were analyzed by measuring the production of IGFBP1 and PRL. Also, the effects of quercetin on intracellular cAMP levels and cellular oxidative stress responses were measured. Phosphokinase arrays, western blotting, and flow cytometry methods were performed to define the effects of quercetin on various signaling pathways and the potential mechanistic roles of quercetin. RESULTS: Quercetin significantly promotes decidualization of control- and endometriosis-endometrial stromal cells. Quercetin substantially reduces the phosphorylation of multiple signaling molecules in the AKT and ERK1/2 pathways, while enhancing the phosphorylation of p53 and total p53 levels. Furthermore, p53 inhibition blocks decidualization while p53 activation promotes decidualization. Finally, we provide evidence that quercetin increases apoptosis of endometrial stromal cells with a senescent-like phenotype. CONCLUSIONS: These data provide insight into the mechanisms of action of quercetin on endometrial stromal cells and warrant future clinical trials to test quercetin and other senolytics for treating endometriosis.

Effect of a novel copper chloride gel on endometrial growth and function in healthy volunteers.

RESEARCH QUESTION: Does the application of a micro-dose of copper chloride gel increase endometrial production of vascular endothelial growth factor (VEGF) without compromising endometrial function or producing embryo toxicity? DESIGN: An estimate of optimal dose was made based on cell culture studies. Ten healthy participants received an initial uterine application of placebo gel, followed by copper chloride gel (37.5 µM, 75 µM, or 150 µM dose) in a later hormone replacement cycle. Endometrial biopsies (day 5.5 luteal) and pelvic ultrasound were carried out during each cycle to evaluate endometrial function and growth. Uterine fluid was assessed for residual copper levels on the day of biopsy, and copper chloride gel underwent mouse embryos assay assessment for potential embryo toxicity. RESULTS: The copper gel significantly increased endometrial VEGF expression (quantitative polymerase chain reaction), and also increasing endometrial thickness by an average of 2.2 mm compared with matched control cycles. The copper gel did not adversely affect endometrial morphology or maturation (histological dating and molecular receptivity testing), and mouse embryos assay studies showed no evidence of embryo toxicity. Furthermore, uterine cavity flush samples mostly lacked copper, with only negligible amounts present in one sample. CONCLUSION: Applying copper chloride gel to the uterine cavity upregulated endometrial VEGF and significantly increased endometrial thickness and volume. No adverse effects on the endometrium or embryos were observed. Copper chloride gels show promise for treating suboptimal endometrial thickness if the results of this study are confirmed by larger randomized controlled trials.

Endometrial preparation protocols did not impact pregnancy outcomes of patients with cured chronic endometritis.

RESEARCH QUESTION: Do endometrial preparation protocols have an effect on pregnancy outcomes in patients with cured chronic endometritis? DESIGN: A retrospective study was conducted on 3721 infertile patients from December 2018 to August 2020. Endometrial tissues obtained during the proliferative phase were immunostained for CD138. The presence of CD138-positive cells within the stromal cells indicated chronic endometritis. All patients diagnosed with chronic endometritis received oral antibiotics. Patients underwent endometrial preparation and frozen embryo transfer once chronic endometritis was cured. This study compared various endometrial preparation protocols to assess their effects on pregnancy outcomes. Additionally, it aimed to investigate differences in pregnancy outcomes between patients without chronic endometritis and patients with cured chronic endometritis while following the same endometrial preparation protocol. RESULTS: Almost no differences in pregnancy outcomes were observed between natural cycle, hormone replacement therapy (HRT) and gonadotrophin-releasing hormone agonist-HRT (GnRH agonist-HRT) protocols in patients without chronic endometritis and patients with cured chronic endometritis. The only notable difference was that, among women without chronic endometritis, the early miscarriage rate was higher for the GnRH agonist-HRT protocol (25.8%) compared with the natural cycle (17.4%) and HRT (17.7%) protocols (P = 0.025). However, this difference was not significant after adjusting for confounders (adjusted OR 1.383, 95% CI 0.931-2.055). The live birth rate, clinical pregnancy rate, early miscarriage rate, ectopic pregnancy rate and ongoing pregnancy rate did not differ significantly (P > 0.05) between patients without chronic endometritis and patients with cured chronic endometritis who underwent natural cycle, HRT and GnRH agonist-HRT protocols. CONCLUSION: Endometrial preparation protocols had no impact on pregnancy outcomes in patients with cured chronic endometritis.

Blockage of the NLRP3 inflammasome by MCC950 inhibits migration and invasion in adenomyosis.

RESEARCH QUESTION: Does the NOD-like receptor protein 3 (NLRP3) inflammasome have an effect in adenomyosis? DESIGN: Fresh-frozen endometrial tissues and paraffin specimens were obtained from endometrial tissues from patients with adenomyosis and controls. Western blot, quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC) were applied to assess expression of the NLRP3 inflammasome components. Primary eutopic endometrial stromal cells were isolated from the uteri of patients with adenomyosis. After NLRP3 was knocked down using small interfering RNA, proliferation, invasion and epithelial-mesenchymal transition (EMT) were evaluated using EdU, CCK8, transwell assays and western blot. Importantly, a mouse model of adenomyosis was established to evaluate the effects of the NLRP3 inhibitor MCC950 on the formation of adenomyosis. RESULTS: Expression of the NLRP3 inflammasome components was elevated in the ectopic or eutopic endometrium of patients with adenomyosis. NLRP3 knockdown inhibited migration, invasion and EMT in endometrial cells and primary endometrial cells (P < 0.0001). MCC950, which blocks the NLRP3 inflammasome, reduced migration and invasion of endometrial cells (P < 0.01) and primary endometrial cells (P < 0.0001) considerably. Importantly, in the mouse model of adenomyosis, MCC950 had a mitigating effect on the severity of adenomyosis (P < 0.01). CONCLUSIONS: NLRP3 was found to enhance migration, invasion and EMT of human endometrial cells in adenomyosis. Notably, the NLRP3 inhibitor MCC950 reduced migration and invasion of endometrial cells effectively. Furthermore, in the mouse model of adenomyosis, MCC950 exhibited a therapeutic effect by alleviating the severity of adenomyosis.

Meclizine improves endometrial repair and reduces simulated menstrual bleeding in mice with induced adenomyosis.

BACKGROUND: Adenomyosis is one of the structural causes of abnormal uterine bleeding, which often presents as heavy menstrual bleeding. Mostly because of the poor understanding of its pathophysiology, medical management of adenomyosis-induced heavy menstrual bleeding is still a challenge. We have previously reported that glycolysis is crucial to endometrial repair following menstruation and that suppressed glycolysis can cause heavy menstrual bleeding. OBJECTIVE: This study aimed to test the hypothesis that meclizine, a drug with an excellent safety profile, alleviates heavy menstrual bleeding in mice with induced adenomyosis using a simulated menstruation model. STUDY DESIGN: Adenomyosis was induced in 36 female C57BL/6 mice using endometrial-myometrial interface disruption. Three months after induction, the mice were randomly divided into the following 3 groups: low-dose meclizine, high-dose meclizine, and controls. Treatment with meclizine or vehicle started shortly before the simulated menstruation procedure and ended before progesterone withdrawal. The amount of blood loss was quantified and uterine tissue was harvested for histologic evaluation of the grade of endometrial repair. We performed immunohistochemistry analysis of 4 proteins critically involved in glycolysis: Glut1 (glucose transporter 1), Hk2 (hexokinase 2), Pfkfb3 (6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3), and Pkm2 (pyruvate kinase M2). The extent of tissue fibrosis in both ectopic and eutopic endometria was evaluated using Masson trichrome staining. RESULTS: In mice with induced adenomyosis, meclizine accelerated endometrial repair in a dose-dependent manner and reduced the amount of menstrual bleeding. Meclizine administration raised endometrial immunoexpression of Hk2 and Pfkfb3 but not of Glut1 or Pkm2. The extent of endometrial fibrosis was reduced following the meclizine administration. Remarkably, these favorable changes were accompanied by the suppression of lesional progression, as evidenced by the dose-dependent reduction in the extent of fibrosis (a surrogate for lesional progression). CONCLUSION: These encouraging results, taken together, suggest that glycolysis may be a promising therapeutic target and that meclizine may hold therapeutic potential as a nonhormonal treatment for adenomyosis-induced heavy menstrual bleeding without exacerbating the disease.

The effect of Norethisterone acetate on the uterus of albino rats: histological, histochemical and ultrastructure study.

BACKGROUND: Norethisterone acetate (NETA), also known as norethindrone acetate is a progestogens medication that is widely used in birth control pills, menopausal hormone therapy, and for the treatment of gynecological disorders as abnormal uterine bleeding and endometriosis. There is a lack of detailed histological information regarding the effects of NETA on the uterine structure. So, the present study focuses on the uterine histological, histochemical and ultrastructure changes following the exposure to NETA in the albino rats. To do this aim, fourteen adult female albino rats were used. They were randomly divided into two equally groups: Control group and NETA treated group. Albino rats of control group were administered daily food, water and orally distilled water only, while rats of NETA treated group were administered daily orally 20 µg of NETA dissolved in 2 ml distilled water, food, and water. The experiment was continued for three weeks. RESULTS: The findings of the present work indicated that the use of NETA has negative effects on the endometrial epithelium (proliferation, autophagy and apoptosis), glands (necrotic, apoptotic or pseudosecretory glands) and stromal and myometrial reactions (granulocytes, connective tissue remodeling, apoptosis, myocytes hypertrophy). CONCLUSION: This work revealed that NETA has desynchronized progestogenic effect on the uterine tissues of the albino rat and thereby prevent implantation and pregnancy.

Selenium elicited an enhanced anti-inflammatory effect in primary bovine endometrial stromal cells with high cortisol background.

BACKGROUND: An elevated endogenous cortisol level due to the peripartum stress is one of the risk factors of postpartum bovine uterine infections. Selenium is a trace element that elicits anti-inflammation and antioxidation properties. This study aimed to reveal the modulatory effect of selenium on the inflammatory response of primary bovine endometrial stromal cells in the presence of high-level cortisol. The cells were subjected to lipopolysaccharide to establish cellular inflammation. The mRNA expression of toll-like receptor 4 (TLR4), proinflammatory factors, and selenoproteins was measured with qPCR. The activation of NF-κB and MAPK signalling pathways was detected with Western blot and immunofluorescence. RESULTS: The pretreatment with sodium selenite (2 and 4 µΜ) resulted in a down-regulation of TLR4 and genes encoding proinflammatory factors, including interleukin (IL)-1ß, IL-6, IL-8, tumour necrosis factor α, cyclooxygenase 2, and inducible nitric oxide synthase. Selenium inhibited the activation of NF-κB and the phosphorylation of mitogen-activated protein kinase kinase, extracellular signal-regulated kinase, p38MAPK and c-Jun N-terminal kinase/stress-activated protein kinase. The suppression of those genes and pathways by selenium was more significant in the presence of high cortisol level (30 ng/mL). Meanwhile the gene expression of glutathione peroxidase 1 and 4 was promoted by selenium, and was even higher in the presence of cortisol and selenium. CONCLUSIONS: The anti-inflammatory action of selenium is probably mediated through NF-κB and MAPK, and is augmented by cortisol in primary bovine endometrial stromal cells.

Tryptophan regulates the expression of IGFBP1 in bovine endometrial epithelial cells in vitro via the TDO2-AHR pathway.

BACKGROUND: This study aimed to identify the roles of L-tryptophan (Trp) and its rate-limiting enzymes on the receptivity of bovine endometrial epithelial cells. Real-time PCR was conducted to analyze the differential expression of genes between different groups of bovine endometrial epithelial cells. Western blot was performed to detect Cyclooxygenase-2 (COX2) expression after treatment with Trp or kynurenine (the main metabolites of Trp). The kynurenine assay was used to examine if Trp or prostaglandin E2 (PGE2) can increase the production of kynurenine in the bovine endometrial epithelial cells. RESULTS: Trp significantly stimulates insulin growth factor binding protein 1 (IGFBP1) expression, a common endometrial marker of conceptus elongation and uterus receptivity for ruminants. When bovine endometrial epithelial cells are treated with Trp, tryptophan hydroxylase-1 remains unchanged, but tryptophan 2,3-dioxygenase 2 (TDO2) is significantly increased, suggesting tryptophan is mainly metabolized through the kynurenine pathway. Kynurenine significantly stimulates IGFBP1 expression. Furthermore, Trp and kynurenine significantly increase the expression of aryl hydrocarbon receptor (AHR). CH223191, an AHR inhibitor, abrogates the induction of Trp and kynurenine on IGFBP1. PGE2 significantly induces the expression of TDO2, AHR, and IGFBP1. CONCLUSIONS: The regulation between Trp / kynurenine and PGE2 may be crucial for the receptivity of the bovine uterus.