Receptivity In Mice Research Articles

Yueliang Yin Ameliorates Endometrial Receptivity in Mice with Embryo Implantation Failure by Reducing Pyroptosis and Activating BDNF/TrkB Pathway.

Endometrial receptivity plays a vital role in embryonic implantation. Yueliang Yin is a marketed solid drink in China, also known as Bushen Cuyun Recipe (BCR), that is, assumed to have a therapeutic effect on infertility by improving endometrial receptivity. This study investigates the effects and mechanisms of BCR in protecting the endometrium. Mice with mifepristone-induced embryo implantation failure that exhibited a decreased implantation sites number, thinner endometrium, reduced endometrial glands number, and poor pinopode expression levels are treated with BCR, and these mentioned conditions significantly improves afterward. Molecular docking shows that the main active components kaempferol, quercetin, and hesperetin of BCR stably bound to gasdermin D (GSDMD). Experimental results demonstrate that levels of GSDMD, cleaved caspase-1 and leucine-rich repeat, and pyrin domain-containing 3 and IL-1β levels in model mice are significantly decreased and expressions of brain-derived neurotrophic factor (BDNF) and tyrosine protein kinase B (TrkB) expression levels are significantly elevated after BCR treatments, and that the DNA damage is significantly reversed in BCR-treated mice. BCR is potent and effective in ameliorating endometrial receptivity. The potential mechanisms of BCR on endometrial receptivity may mediate by activating BDNF/TrkB pathway activation and protecting endometrial cells' protection against pyroptosis.

Regulatory T cells are paramount effectors in progesterone regulation of embryo implantation and fetal growth.

Progesterone (P4) is essential for embryo implantation, but the extent to which the pro-gestational effects of P4 depend on the maternal immune compartment is unknown. Here, we investigate whether regulatory T cells (Treg cells) act to mediate luteal phase P4 effects on uterine receptivity in mice. P4 antagonist RU486 administered to mice on days 0.5 and 2.5 postcoitum to model luteal phase P4 deficiency caused fewer CD4+Foxp3+ Treg cells and impaired Treg functional competence, along with dysfunctional uterine vascular remodeling and perturbed placental development in midgestation. These effects were linked with fetal loss and fetal growth restriction, accompanied by a Th1/CD8-skewed T cell profile. Adoptive transfer at implantation of Treg cells - but not conventional T cells - alleviated fetal loss and fetal growth restriction by mitigating adverse effects of reduced P4 signaling on uterine blood vessel remodeling and placental structure and by restoring maternal T cell imbalance. These findings demonstrate an essential role for Treg cells in mediating P4 effects at implantation and indicate that Treg cells are a sensitive and critical effector mechanism through which P4 drives uterine receptivity to support robust placental development and fetal growth.

Uterine administration of C-X-C motif chemokine ligand 12 increases the pregnancy rates in mice with induced endometriosis

To study the effect of intrauterine injection of C-X-C motif chemokine ligand 12 (CXCL12), also known as a stem cell chemoattractant (stromal cell-derived factor 1), on fertility and endometrial receptivity in mice with endometriosis. Laboratory study. Academic Medical Center. Fifty-six mice underwent chemotherapy and bone marrow transplantation. Thirty-six of these mice underwent either surgery to induce endometriosis (n = 20) or sham surgery (n = 16). Injection of CXCL12 as a potential therapeutic agent to improve fertility in endometriosis. Pregnancy rate, bone marrow-derived cell (BMDC) recruitment and endometrial receptivity markers. The mice with or without endometriosis received a single uterine injection of either CXCL12 or placebo. Uterine injection of CXCL12 increased the pregnancy rates in a mouse model of endometriosis. Mice were euthanized after delivery, and implantation markers homeobox A11, alpha-v beta-3 integrin, and progesterone receptor were analyzed by immunohistochemistry, whereas green fluorescent protein positive BMDC recruitment was quantified by immunohistochemistry and immunofluorescence. The sham surgery groups without endometriosis had the highest cumulative pregnancy rate (100%) regardless of CXCL12 treatment. The endometriosis group treated with placebo had the lowest pregnancy rate. An increased pregnancy rate was noted in the endometriosis group after treatment with CXCL12. There was also an increase in BMDC recruitment and endometrial expression of progesterone receptor and alpha-v beta-3 integrin in the endometriosis group that received CXCL12 compared with that in the endometriosis group that received placebo. Uterine injection of CXCL12 increased the pregnancy rates in a mouse model of endometriosis. These results suggest that CXCL12 has a potential role as a therapeutic agent in women with infertility related to endometriosis and potentially other endometrial receptivity defects.

Tiaojing Cuyun Recipe Enhances Pregnancy Outcome via the VEGF/PI3K/AKT/eNOS Signaling Pathway in EID Mice.

Purpose In this study, we evaluated the effect of Tiaojing Cuyun Recipe (TJCYR) on embryo implantation dysfunction- (EID-) induced damage of endometrial receptivity in mice and investigated the mechanisms underlying the effect. Methods The main compounds of TJCYR were identified by high-performance liquid chromatography (HPLC). One hundred and twenty pregnant mice were randomly divided into six groups: control, EID only, progesterone (Prog)+EID, TJCYR-low-dose+EID, TJCYR-medium-dose+EID, and TJCYR-high-dose+EID. Mifepristone was injected to make the EID model. On the fourth day of pregnancy, serum was obtained to analyze hormone level by radioimmunoassay, the uterus was collected to analyze morphology by hematoxylin and eosin (H&E) and scanning electron microscopy (SEM), and a combination of immunofluorescence and Western blot was used to identify the related proteins. On the eighth day of pregnancy, the mice were sacrificed and the number of uterus-implanted blastocysts was counted. Results Treatment with TJCYR significantly improved the number of implanted sites, the number of well-developed pinopodes, and microvascular formation in the mice. Moreover, TJCYR significantly activated PI3K/Akt/eNOS signaling pathways to promote angiogenesis, resulting in significantly improved endometrial receptivity and fertility outcomes when compared to the model group. Conclusion These findings demonstrate that TJCYR was able to protect embryo implantation of EID mice due to TJCYR-mediated improvement in endometrial receptivity by promoting endometrial angiogenesis.

Deciphering mouse uterine receptivity for embryo implantation at single-cell resolution.

ObjectivesMice are widely used as an animal model for studying human uterine receptivity for embryo implantation. Although transcriptional changes related to mouse uterine receptivity have been determined by using bulk RNA‐seq, the data are of limited value because the uterus is a complex organ consisting of many cell types. Here, we aimed to decipher mouse uterine receptivity for embryo implantation at single‐cell resolution.Materials and methodsSingle‐cell RNA sequencing was performed for the pre‐receptive and the receptive mouse uterus. Gene expression profiles in luminal epithelium and glandular epithelium were validated by comparing against a published laser capture microdissection (LCM)‐coupled microarray dataset.ResultsWe revealed 19 distinct cell clusters, including 3 stromal cell clusters, 2 epithelial cell clusters, 1 smooth muscle cell cluster, 4 endothelial cell clusters and 8 immune cell clusters. We identified global gene expression changes associated with uterine receptivity in each cell type. Additionally, we predicted signalling interactions for distinct cell types to understand the crosstalk between the blastocyst and the receptive uterus.ConclusionOur data provide a valuable resource for deciphering the molecular mechanism underlying uterine receptivity in mice.

Regulation mechanism of miR-494-3p on endometrial receptivity in mice via PI3K/AKT/mTOR pathway.

Successful implantation requires endometrial receptivity. To investigate the mechanisms of miR-494-3p on endometrial receptivity, GnRHa's superovulation scheme was designed to reduce endometrial receptivity, and the pregnant mice were injected with miR-494-3p antagomir. The regulatory role of miR-494-3p was identified by RT-qPCR, uterine blastocyst count, scanning electron microscopy, hematoxylin-eosin (HE) staining, and Western blot. Results indicated that miR-494-3p antagomir increased uterine blastocysts numbers, promoted the pinocytosis expressions, and increased endometrial thickness. Besides, miR-494-3p antagomir significantly increased leukemia inhibitory factor (LIF), Ang-2 and VEGF protein expressions, and up-regulated p-AKT/AKT and p-mTOR/mTOR protein ratios in endometrium. Luciferase assay confirmed that LIF was a potential target of miR-494-3p. Subsequently, human endometrial epithelial cells (hEECs) were transfected with miR-494-3p inhibitor and PI3K inhibitor (LY294002). The role of miR-494-3p was identified by RT-qPCR, CCK-8 assay, transwell assay and flow cytometry. Results indicated that miR-494-3p inhibitor significantly increased proliferation and invasion, and significantly inhibited apoptosis in hEECs, while LY294002 reversed its biological function. Overall, these results suggested that miR-494-3p is the key regulator of endometrial receptivity in mice, regulating this complex process through the PI3K/AKT/mTOR pathway. Understanding the role of miR-494-3p in endometrial receptivity is of great significance for exploring new targets for the diagnosis and treatment of early pregnancy failure, and improving the success rates of artificial reproduction.

Cisplatin decreases HOXA13 and alphaVBeta3 integrin levels in the uterus

ObjectiveTo examine the effects of cisplatin on uterine histology and implantation molecules and the possible protective role of recombinant Klotho administration on uterine histology and uterine receptivity in mice exposed to cisplatin. Materials and methodsThis study was conducted using thirty-two adult female mice assigned to four groups with 8 mice in each group. Saline was given to the 1st group, cisplatin to the 2nd group, recombinant mouse Klotho to the 3rd group and recombinant mouse Klotho plus cisplatin to the 4th group. Uterine tissues were examined for damage histologically and immunobiologically for the uterine receptivity markers HOXA13 and alphaVBeta3 integrin. ResultsApoptosis, degeneration, decrease in uterine thickness and uterine absence of gland scores were higher in the cisplatin group (3rd group) compared to the saline group (1st group) (cisplatin vs. saline p < 0.0001 for all parameters). In the recombinant Klotho plus cisplatin group (4th group), scores of apoptosis, degeneration, reduction in uterine thickness and uterine absence of gland were lower than the group receiving only cisplatin (cisplatin plus recombinant Klotho vs cisplatin, p = 0.006 for apoptosis; p = 0.017 for degeneration; p = 0.011 for the reduction in uterine thickness; p = 0.002 for the absence of gland). However, HOXA13 and alphaVBeta3 integrin staining levels were not different between the cisplatin group (group 3) and the cisplatin plus recombinant Klotho group (group 4) (p = 0.980 and p = 0.762, respectively.) ConclusionCisplatin has adverse effects on the uterus. Administration of recombinant Klotho was found to attenuate the cisplatin-induced damage but failed to preserve levels of the implantation molecules HOXA13 and alphaVbeta3. Further studies examining the effect of cisplatin toxicity using other implantation markers along with functional studies are needed.

CXCL12 enhances pregnancy outcome via improvement of endometrial receptivity in mice

Successful pregnancy inevitably depends on the implantation of a competent embryo into a receptive endometrium. Although many substances have been suggested to improve the rate of embryo implantation targeting enhancement of endometrial receptivity, currently there rarely are effective evidence-based treatments to prevent or cure this condition. Here we strongly suggest minimally-invasive intra-uterine administration of embryo-secreted chemokine CXCL12 as an effective therapeutic intervention. Chemokine CXCL12 derived from pre- and peri-implanting embryos significantly enhances the rates of embryo attachment and promoted endothelial vessel formation and sprouting in vitro. Consistently, intra-uterine CXCL12 administration in C57BL/6 mice improved endometrial receptivity showing increased integrin β3 and its ligand osteopontin, and induced endometrial angiogenesis displaying increased numbers of vessel formation near the lining of endometrial epithelial layer with higher CD31 and CD34 expression. Furthermore, intra-uterine CXCL12 application dramatically promoted the rates of embryo implantation with no morphologically retarded embryos. Thus, our present study provides a novel evidence that improved uterine endometrial receptivity and enhanced angiogenesis induced by embryo-derived chemokine CXCL12 may aid to develop a minimally-invasive therapeutic strategy for clinical treatment or supplement for the patients with repeated implantation failure with less risk.

Regulation mechanism of miR-494-3p on endometrial receptivity in mice via PI3K/AKT/mTOR pathway

Successful implantation requires endometrial receptivity. To investigate the mechanisms of miR-494-3p on endometrial receptivity, GnRHa's superovulation scheme was designed to reduce endometrial receptivity, and the pregnant mice were injected with miR-494-3p antagomir. The regulatory role of miR-494-3p was identified by RT-qPCR, uterine blastocyst count, scanning electron microscopy, hematoxylin-eosin (HE) staining, and Western blot. Results indicated that miR-494-3p antagomir increased uterine blastocysts numbers, promoted the pinocytosis expressions, and increased endometrial thickness. Besides, miR-494-3p antagomir significantly increased leukemia inhibitory factor (LIF), Ang-2 and VEGF protein expressions, and up-regulated p-AKT/AKT and p-mTOR/mTOR protein ratios in endometrium. Luciferase assay confirmed that LIF was a potential target of miR-494-3p. Subsequently, human endometrial epithelial cells (hEECs) were transfected with miR-494-3p inhibitor and PI3K inhibitor (LY294002). The role of miR-494-3p was identified by RT-qPCR, CCK-8 assay, transwell assay and flow cytometry. Results indicated that miR-494-3p inhibitor significantly increased proliferation and invasion, and significantly inhibited apoptosis in hEECs, while LY294002 reversed its biological function. Overall, these results suggested that miR-494-3p is the key regulator of endometrial receptivity in mice, regulating this complex process through the PI3K/AKT/mTOR pathway. Understanding the role of miR-494-3p in endometrial receptivity is of great significance for exploring new targets for the diagnosis and treatment of early pregnancy failure, and improving the success rates of artificial reproduction.

Secretory phospholipase A2-X (Pla2g10) is a novel progesterone receptor target gene exclusively induced in uterine luminal epithelium for uterine receptivity in mice

BackgroundAberration of estrogen (E2) and/or progesterone (P4) signaling pathways affects expression of their target genes, which may lead to failure of embryo implantation and following pregnancy. Although many target genes of progesterone receptors (PRs) have been identified in uterine stroma, only a few PR targets have been reported in the epithelium. Secretory phospholipase A2-(PLA2)-X, a member of the PLA2 family that releases arachidonic acids for the synthesis of prostaglandins that are important for embryo implantation, is dysregulated in the endometrium of patients suffering from repeated implantation failure. However, it is not clear whether sPLA2-X is directly regulated by ovarian steroid hormones for embryo implantation in the uterus.ResultP4 induced the Pla2g10 encoding of secretory PLA2-X in the apical region of uterine LE of ovariectomized mice via PR in both time- and dose-dependent manners, whereas E2 significantly inhibited it. This finding is consistent with the higher expression of Pla2g10 at the diestrus stage, when P4 is elevated during the estrous cycle, and at P4-treated delayed implantation. The level of Pla2g10 on day 4 of pregnancy (day 4) was dramatically decreased on day 5, when PRs are absent in the LE. Luciferase assays of mutagenesis in uterine epithelial cells demonstrated that four putative PR response elements in a Pla2g10 promoter region are transcriptionally active for Pla2g10. Intrauterine delivery of small interfering RNA for Pla2g10 on day 3 significantly reduced the number of implantation sites, reinforcing the critical function(s) of Pla2g10 for uterine receptivity in mice.ConclusionsPla2g10 is a novel PR target gene whose expression is exclusively localized in the apical region of the uterine LE for uterine receptivity for embryo implantation in mice.

TGF-β1 Neutralization Improves Pregnancy Outcomes by Restoring Endometrial Receptivity in Mice with Adenomyosis.

The objective of this research is to study the effects of TGF-β1 inhibition on endometrial receptivity and pregnancy outcomes in mice with adenomyosis. Experiments were done using a mouse model of adenomyosis which took place in a hospital-affiliated laboratory. The mouse model used for this research is ICR mouse. Adenomyosis was induced by oral gavage of tamoxifen (TAM) from postnatal days (PNDs) 1 to 4 in ICR mice. Bilateral intrauterine injection of anti-TGF-β1-neutralizing antibody or isotype IgG or PBS was performed at PND42. The mice were then either sacrificed or mated at PND64 followed by sacrificing at gestational day (GD) 4 or proceeding to delivery. Implantation numbers, rate of dams with live birth, live birth numbers, survival at 1week old, and pup mortality rate after weaning were recorded. Collagen was demonstrated by Masson's trichrome and Van Gieson's stains. Uterine expression of a receptivity marker, leukemia inhibitory factor (LIF), was examined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR), Western blot, and immunohistochemistry (IHC). Anti-TGF-β1 treatment increased the mean implantation numbers, fecundity rate, the rate of dams with live birth, pup survival rate at 1week old, and pup mortality rate after weaning. Collagen expression in uteri with adenomyosis was attenuated by anti-TGF-β1 treatment. Increased LIF expression by anti-TGF-β1 treatment was detected by qRT-PCR, Western blot, and IHC. The results suggest that inhibition of TGF-β1 improves pregnancy outcomes by restoring endometrial receptivity in mice with adenomyosis.

The effect of fludrocortisone on the uterine receptivity partially mediated by ERK1/2-mTOR pathway.

Implantation of embryos needs endometrial receptivity. Mineralocorticoids is one of the causes influencing the implantation window. This study targeted to evaluation fludrocortisone different properties on endometrial receptivity. The objective of this study was to assess whether treatment with fludrocortisone could impact the expression of diverse genes and proteins that are involved in uterine receptivity in mice. In this study, 40 female adult BALB/c mice were used. The samples were allocated to four groups of ten. Control group (C) received: vehicle; fludrocortisone group (FCA): received 1.5 mg/kg fludrocortisone; PP242 group (PP242): received 30 mg/kg PP242; fludrocortisone+PP242 group (FCA+PP242): received fludrocortisone and PP242. Mice were killed on window implantation day after mating and confirmed pregnancy. The endometrial epithelium of mouse was collected to assess mRNA expression of leukemia inhibitory factor (LIF), mucin-1 (MUC1), heparin-binding epidermal growth factor (HB-EGF), (Msx.1), miRNA Let-7a, and miRNA 223-3p as well as protein expression of extracellular signal-regulated kinase 1/2 (ERK1/2), mammalian target of rapamycin (mTOR), and eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) in the uterine using real-time PCR and western blot, respectively. In comparison with the control group, fludrocortisone administration upregulated the expression of LIF, HB-EGF, Msx.1, miRNA Let-7a, ERK1/2, and mTOR in the epithelial endometrium. The PP242-treated group demonstrated a significant rise in the expression of MUC1, miRNA 223-3p and a remarkable decline in ERK1/2 and p-4E-BP1 levels in comparison with the control group. Combination therapy of (FCA+PP242) resulted in a remarkable rise in LIF, Msx-1, HB-EGF, ERK1/2, and mTOR levels, in comparison with the PP242 group. Furthermore, combination therapy of (FCA+PP242) downregulated the expression of MUC1 in comparison with the PP242-treated group. According to the results, fludrocortisone affected uterine receptivity possibly by means of modulating the expression of genes involved in the uterine receptivity and activation of the ERK1/2-mTOR pathway.

Identification of Gene Expression Changes Associated With Uterine Receptivity in Mice.

The mouse is a widely used animal model for studying human reproduction. Although global gene expression changes associated with human uterine receptivity have been determined by independent groups, the same studies in the mouse are scarce. The extent of similarities/differences between mice and humans on uterine receptivity at the molecular level remains to be determined. In the present study, we analyzed global gene expression changes in receptive uterus on day 4 of pregnancy compared to non-receptive uterus on day 3 of pregnancy in mice. A total of 541 differentially expressed genes were identified, of which 316 genes were up-regulated and 225 genes were down-regulated in receptive uterus compared to non-receptive uterus. Gene ontology and gene network analysis highlighted the activation of inflammatory response in the receptive uterus. By analyzing the promoter sequences of differentially expressed genes, we identified 12 causal transcription factors. Through connectivity map (CMap) analysis, we revealed several compounds with potential anti-receptivity activity. Finally, we performed a cross-species comparison against human uterine receptivity from a published dataset. Our study provides a valuable resource for understanding the molecular mechanism underlying uterine receptivity in mice.

Calcitonin administration improves endometrial receptivity via regulation of LIF, Muc-1 and microRNA Let-7a in mice.

Calcitonin (CT) is one of the factors affecting the embryo implantation, but its effects on the implantation window have not been fully investigated. The current study investigated the effects of CT on the endometrium receptivity by morphological study and evaluation of leukemia inhibitory factor (LIF), mucin 1 (Muc-1), and microRNA (miRNA) Let-7a in the ovarian stimulation and the normal ovarian cycle. Then the mechanism of the CT effects through the mammalian target of rapamycin (mTOR) signaling pathway was studied by using PP242. A total of 64 BALB/c mice were divided into the normal ovarian cycle and ovarian stimulation groups. Each group consisted of four subgroups: control, calcitonin, PP242, and calcitonin+PP242. CT and PP242 were injected on the fourth of pregnancy into the mice and 24 hr later all the mice were killed. The uterine tissue samples were used for morphological analysis, and endometrial cells were mechanically isolated for evaluation of gene and protein expression. The results showed that ovarian stimulation induced mTOR phosphorylation as well as increased expression of the Let-7a miRNA. In addition, CT injection increased the expression of LIF and miRNA Let-7a in ovarian stimulation similar to that in normal ovarian cycles. However, injection of PP242 reduced expression of miRNA Let-7a and increased Muc-1 expression in ovarian stimulation group. In conclusion, the administration of CT improved endometrial receptivity in mice. This phenomenon occurred by upregulation of LIF, miRNA Let-7a and downregulation of Muc-1 via mTOR signaling pathway.

Caffeine consumption during early pregnancy impairs oviductal embryo transport, embryonic development and uterine receptivity in mice.

Caffeine consumption has been widely used as a central nervous system stimulant. Epidemiological studies, however, have suggested that maternal caffeine exposure during pregnancy is associated with increased abnormalities, including decreased fertility, delayed conception, early spontaneous abortions, and low birth weight. The mechanisms underlying the negative outcomes of caffeine consumption, particularly during early pregnancy, remain unclear. In present study, we found that pregnant mice treated with moderate (5 mg/kg) or high (30 mg/kg) dosage of caffeine (intraperitoneally or orally) during preimplantation resulted in retention of early embryos in the oviduct, defective embryonic development, and impaired embryo implantation. Transferring normal blastocysts into the uteri of caffeine-treated pseudopregnant females also showed abnormal embryo implantation, thus indicating impaired uterine receptivity by caffeine administration. The remaining embryos that managed to implant after caffeine treatment also showed increased embryo resorption rate and abnormal development at mid-term stage, and decreased weight at birth. In addition to a dose-dependent effect, significant variations between individual mice under the same caffeine dosage were also observed, suggesting different sensitivities to caffeine, similar to that observed in human populations. Collectively, our data revealed that caffeine exposure during early pregnancy impaired oviductal embryo transport, embryonic development, and uterine receptivity, which are responsible for abnormal implantation and pregnancy loss. The study raises the concern of caffeine consumption during early stages of pregnancy.

Sorcin is involved during embryo implantation via activating VEGF/PI3K/Akt pathway in mice.

Our earlier studies have demonstrated the cyclic variation and also the altered expression of sorcin in endometrium during early-to-mid-secretory phase transition in women with unexplained infertility. The current study was undertaken to establish the functional role of sorcin in endometrial receptivity in mice. Results indicated that sorcin was highly expressed during the window of implantation in mice and functional blockage of sorcin caused significant reduction in number of implanted blastocyst. The receptivity markers (i.e.Integrin β3, HBEGF, IGFBP1, WNT4 and Cyclin E)) were found to be downregulated in sorcin knocked down uterine horn on day 5 as compared to untreated horn. The reduced attachment and expansion of BeWo spheroids on RL95-2 endometrial cells with sorcin knock down, in in vitro model of endometrium-trophoblast interaction further supported these findings. Uterine sorcin expression pattern during estrous cycle and in delayed implantation mice model suggested the upregulation of sorcin by estrogen. The functional blockade of sorcin induced the intracellular Ca+2 levels in endometrial epithelial cells (EECs), which indicated that altered Ca+2 homeostasis might be responsible for implantation failure. Sorcin silencing led to significant reduction in the expression of angiogenic factor VEGF and its downstream effector molecules i.e. PI3K, Akt and NOS. The migratory and invasive properties of HUVECs were abrogated by anti-VEGF or by adding culture media from sorcin blocked EECs, which indicated that sorcin might mediate angiogenesis during implantation. Taken together, sorcin is involved in the regulation of Ca+2-mediated angiogenesis via VEGF/PI3K/Akt pathway in endometrial cells and plays a crucial role in preparing the endometrium for implantation.

Prospective evaluation of uterine receptivity in mice.

In current infertility treatments it is necessary to evaluate uterine receptivity in each menstrual cycle. During the implantation period, the uterus goes through many complex orchestrated changes, including changes to the glycocalyx. The changes to the glycocalyx are due to sialylation, sulfation and fucosylation. Can the measurement of in-vivo uterine pH and/or oxidation-reduction potential (ORP) determine the alterations of uterine endometrium for implantation and evaluate prospective uterine receptivity? In the present study we assessed in vivo uterine pH and ORP during the early stages of pregnancy in naïve mice, as well as in a murine model of implantation failure created by local and transient suppression of signal transducer and activator of transcription 3. There was no change in the in vivo uterine pH between post-coitus Days 2 and 6. In vivo uterine ORP was significantly higher compared to the day before. One day before implantation began, uterine ORP was significantly decreased in the implantation failure group compared with the naïve and control groups. Receiver operator characteristic (ROC) curve analysis of uterine ORP as a predictor of non-conception showed an area under the ROC curve of 0.96 (95% confidence interval 0.92-1.00). Thus, in vivo uterine ORP could be a parameter to prospectively evaluate uterine receptivity.

Research Article Effect of You-Gui-Wan on endometrial angiogenesis in controlled ovarian hyperstimulation mice model

Purpose: To explore the mechanism of You-Gui-Wan (YGW) in improving endometrial receptivity in mouse model of controlled ovarian hyperstimulation (COH). Methods: Sixty female mice with two consecutive oestrous cycles were randomly divided into COH model group (n = 50) and normal control group (n = 10). The COH model was created by using GnRH-a + PMSG + HCG and further randomly divided into 5 subgroups of simple model, YGW high-dose, YGW medium-dose, YGW low-dose and aspirin control, 10 in each subgroup. YGW or aspirin or saline was administrated to the mice by gavage once a day for 11 days. Afterwards, blood and uterine samples were collected for examination of serum levels of estradiol (E2) and progesterone (P4), endometrial thickness and number of blood vessels as well as expressions of angiogenic factors of VEGF, Ang-1, Ang-2 and Tie-2 at transcription and translation levels by using H& E staining, ELISA, real-time qRT-PCR, and immunohistochemistry, respectively. Results: COH per se increased the serum concentrations of E2 and P4i¼Œbut decreased the number of endometrial blood vessels and the protein expressions of the angiogenic factors when compared to the normal control group (P< 0.05 or 0.01). YGW increased the mRNA expressions of all angiogenic factors and restored the effect of COH on number of endometrial blood vessels (P< 0.01), and the protein expressions of the angiogenic factors when compared to the COH simple model group (P< 0.05 or 0.01). In comparison, aspirin could only restore the number of endometrial blood vessels and the protein expressions of Ang-2 and Tie-2 (P< 0.05 or 0.01). Conclusions: YGW can restore the side effect of COH on number of endometrial blood vessels and the expressions of angiogenic factors, thus improve endometrial receptivity in COH mice

Differential regulation of receptivity in two uterine horns of a recipient mouse following asynchronous embryo transfer.

Receptivity is a limited time in which uterine endometrium can establish a successful dialogue with blastocyst. This study was to investigate the effect of asynchronous embryo transfer on uterine receptivity in mice. Embryos under different stages were transferred into two oviduct sides of a recipient mouse on day 1 of pseudopregnancy. Our results showed the asynchronously transferred embryos can implant in all groups. Compared to zygote-transfer group, the length of implanted embryos is longer in 8-cell embryo- or blastocyst-transfer group. The levels of Snail and COX-2 immunostaining in blastocyst-transfer group are significantly stronger than that in zygote-transfer group. Embryos in blastocyst-transfer group migrate faster than that in zygote-transfer group within uterus. Blastocysts are in a state of developmental delay after they are transferred into oviducts, and they are reactivated and implanted rapidly in uterus. The developmental rate to newborn in zygote-transfer group is obviously higher than that in blastocyst-transfer group, suggesting that a delay in embryo development and implantation will lead to a decrease of litter size. These results indicated that the window of implantation is differentially regulated in two uterine horns of a recipient by embryos at different stages.

Intrauterine Administration of Peripheral Blood Mononuclear Cells (PBMCs) Improves Endometrial Receptivity in Mice with Embryonic Implantation Dysfunction

Intrauterine administration of autologous peripheral blood mononuclear cells (PBMCs) activated by HCG in vitro is reported to improve implantation rates in patients with repeated failure of IVF-ET. In this article, the impact of intrauterine administration of PBMCs on embryo implantation, pregnancy rate and the underlying mechanisms will be investigated. Pregnant mice were randomly divided into three groups, including control group; embryo implantation dysfunction (EID) group; EID with PBMCs group. Uterine horns were excised to determine the number of pregnant mice and implantation sites on the Day 7.5 postcoitum. The expression levels of LIF and VEGF during the implantation window were detected with immunohistochemistry and Real Time-PCR analysis. Embryo implantation dysfunction model group showed a significant decrease in pregnancy rate, implantation sites and the expression of both the endometrial LIF and VEGF during the implantation window. EID with PBMCs group showed a higher pregnancy rate and endometrial LIF and VEGF expression compared to EID group. Intrauterine administration of mouse PBMCs derived from unpregnant mice prior to embryo implant has a good influence on endometrial receptivity and embryonic implantation in EID mice.