Embryo Transfer Strategies for Women with Recurrent Implantation Failure During the Frozen-thawed Embryo Transfer Cycles:Sequential Embryo Transfer or Double-blastocyst Transfer?

Objective Both sequential embryo transfer(SeET)and double-blastocyst transfer(DBT)can serve as embryo transfer strategies for women with recurrent implantation failure(RIF).This study aims to compare the effects of SeET and DBT on pregnancy outcomes.Methods Totally,261 frozen-thawed embryo transfer cycles of 243 RIF women were included in this multicenter retrospective analysis.According to different embryo quality and transfer strategies,they were divided into four groups:group A,good-quality SeET(GQ-SeET,n=38 cycles);group B,poor-quality or mixed-quality SeET(PQ/MQ-SeET,n=31 cycles);group C,good-quality DBT(GQ-DBT,n=121 cycles);and group D,poor-quality or mixed-quality DBT(PQ/MQ-DBT,n=71 cycles).The main outcome,clinical pregnancy rate,was compared,and the generalized estimating equation(GEE)model was used to correct potential confounders that might impact pregnancy outcomes.Results GQ-DBT achieved a significantly higher clinical pregnancy rate(aOR 2.588,95%CI 1.267–5.284,P=0.009)and live birth rate(aOR 3.082,95%CI 1.482–6.412,P=0.003)than PQ/MQ-DBT.Similarly,the clinical pregnancy rate was significantly higher in GQ-SeET than in PQ/MQ-SeET(aOR 4.047,95%CI 1.218–13.450,P=0.023).The pregnancy outcomes of GQ-SeET were not significantly different from those of GQ-DBT,and the same results were found between PQ/MQ-SeET and PQ/MQ-DBT.Conclusion SeET relative to DBT did not seem to improve pregnancy outcomes for RIF patients if the embryo quality was comparable between the two groups.Better clinical pregnancy outcomes could be obtained by transferring good-quality embryos,no matter whether in SeET or DBT.Embryo quality plays a more important role in pregnancy outcomes for RIF patients.

Local Immune Regulatory Effects of Bangdeyun on the Endometrium of Mice with Embryo Implantation Dysfunction during the Implantation Time

This study examined the effects of Bangdeyun on the expressions of nuclear factor-kappaB （NF-κB）, interferon-gamma （IFN-y） and interleukin-10 （IL-10） in the endometrium of mice with embryo implantation dysfunction （EID） during the implantation time （namely on pregnancy day 5, 6, 7 and 8） and explored the local immune regulatory effects of Bangdeyun. The gestational mice were randomly divided into normal group, model group and Bangdeyun-treated group. EID models of mice were established by using indomethacin. The endometrial expression of NF-κB was detected by immunohistochemistry and Western blotting. IFN-γ and IL-10 were measured by enzyme-linked immunosorbent assay （ELISA）. The results showed that in the normal group, NF-κB and IFN-γ were weakly expressed and IL-10 was strongly expressed in the endometrium during the whole implantation period. In the model group, the expressions of NF-κB and IFN-T were increased on pregnancy day 5, 6 and 7, and IL-10 expression decreased during the whole implantation time when compared with those in the normal group （P〈0.01 for all）. In the Bangdeyun-treated group, little amount of NF-κB and IFN-γ was expressed and IL-10 expression was strong, much the way they were expressed in the normal group （P〉0.05）. The expressions of NF-κB and IFN-T were much lower in the Bangdeyun-treated group than those in the model group on pregnancy day 5, 6 and 7 （P〈0.01 for all）, while the expression of IL-10 was much higher than in the model group during the whole implantation time （P〈0.01）. It was suggested Bangderun may favor a shift from Thl- to Th2-type immune response, therefore inhibiting the maternal immune rejection, inducing the immune tolerance and improving the fetal implantation.

Effects of Jiantaiye (健胎液) on Estrogen Receptor and mRNA Expressions in Uterus of Mice with Embryo Implantation Dysfunction

Objective: To explore the effect of Jiantaiye (健胎液, JTY) on the expression of estrogen receptor (ER) and ER mRNA in uterus of mice with embryo implantation dysfunction. Methods: Embryo implantation dysfunction mouse models were induced with mifepristone and treated with JTY. All animals were sacrificed on day 8 of pregnancy. The endometrial ER and ER mRNA expressions were assessed by immunnohistochemical SP method and semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR). Results: Area ratio and absorbency of ER in the JTY treated group's gland and stroma were higher than those of the model group, quite similar to those of the normal control's, and ER mRNA expression in treated group's uterus was significantly higher than that in the models, but it was not significantly different from the normal control. Conclusion: JTY improves the endometrial development by increasing ER and ER mRNA expressions of uterus of mice with embryo implantation dysfunction.

Effect of Bushen Yiqi Hexue Recipe (补肾益气和血方) on Pinopodes Expression on Endometrial Surface in Embryo Implantation Dysfunctional Mice

Objective: To explore the therapeutic mechanism of Bushen Yiqi Hexue recipe (补肾益气血方, BYHR), and observe its effect on pinopodes expression on endometrial surface in mifepristone induced embryo implantation dysfunctional mice. Methods: Pregnant Kunming mice were randomly divided into the normal group, the control group and the treated group. Mice in the treated group were administered with BYHR, and those in the normal group and the control group were administered with normal saline, starting from the very first day of pregnancy (Pd1). On the Pd4, mifepristone (RU486) was subcutaneously injected into mice in the control group and the treated group. Pinopodes expression on endometrial surface at 09:30-10:00 pm on Pd4 (regarded as time point 1, T1) and at 09:30-10:00 am on Pd5 (as time point 2, T2) was determined by scanning electron microscopy. Pregnancy rate and average implanted embryos were observed on Pd7. Results: Pregnancy rate and average implanted embryos in the control group were obviously lower than those in the normal group (all P<0.01), while the two parameters were significantly higher in the treated group (P<0.05, P<0.01, respectively) than those in the control group. In the normal group, abundant developing pinopodes were distributed over the whole endometrial surface in T1, and they were altered to a great deal of fully developed pinopodes in T2. But in the control group, only a few pinopodes were expressed locally on endometrial surface in T1, showing a nonsynchronous figure of development, and they completely disappeared in T2. In the treated group, a lot of developing pinopodes were expressed like those in the normal group but somewhat lagged behind, whereas many fully developed pinopodes were expressed in T2. Conclusion: The decrease of the pinopodes in T1 and the cleaning up of them in T2 is possibly the partial mechanism of mifepristone in inducing embryo implantation dysfunction. It is indicated that BYHR could improve pinopodes expression on endometrial surface, eventually better the uterine receptivity and improve the embryo implantation.

Effect of Acupuncture on CXCL8 Receptors in Rats Suffering from Embryo Implantation Failure

To observe the effect of acupuncture on CXCL8 receptors（CXCR1 and CXCR2） in rat endometrium experiencing embryo implantation failure, 72 pregnant rats were randomly divided into four groups： normal group（N）, embryo implantation failure group（M）, acupuncture treatment group（A）, and progestin treatment group（W）. Then the rats in each group were equally randomized into a day-6（D6） group, a day-8（D8） group, and a day-10（D10） group. The rats in group M, group A, and group W were treated with mifepristone-sesame oil solution on day 1, while the rats in group N were injected with the same amount of sesame oil. Meanwhile, ＂Housanli＂ and ＂Sanyinjiao＂ were selected for acupuncture. From day 1 to the time of death, the rats in group A were fastened up and then acupuncture was administered while the rats in group N and group M were only fixed, and the rats in group W were given progestin. The number of implanted embryos was calculated. The expression of CXCR1 and CXCR2 in rat endometrium was detected by immunohistochemistry, Western blotting and real-time PCR. Compared to group N, the average number of implanted embryos, the protein and mRNA expression of CXCR1（D6, D8 and D10）, and the protein and mRNA expression of CXCR2（D8 and D10） in rat endometrium were significantly decreased in group M. Compared to group M, there was significant elevation in the average number of implanted embryos, the protein expression（D6, D8 and D10） and mRNA expression（D8） of CXCR1 in rat endometrium of group A, and the protein expression（D8 and D10） and mRNA expression（D8） of CXCR2 in rat endometrium of group W. These findings indicated that acupuncture can increase the number of implanted embryos in rats of embryo implantation failure, which may be relevant with up-regulation the expression of CXCR1 and CXCR2 at maternal-fetal interface of rats with embryo implantation failure.

Effect of Bushenantai Recipe on the Expression of Endometrial LIF in Mice with Embryonic Implantation Dysfunction

In order to observe the effect of Bushenantai recipe on the expression of endometrial leukemia-inhibitory factor （LIF） in mice with embryonic implantation dysfunction （EID）, 120 Kunming mice post coition were randomized into three groups： normal control group, model group and traditional Chinese medicine group （TCM group） （n=40 in each group）. Uterus was collected on the pregnancy day （Pd） 4, 5, 6 after an intravenous injection of Evan＇s blue. The endometrium was dyed by Evan＇s blue and the mean points of response were observed on Pd 5. The expression of LIF mRNA and protein was detected by RT-PCR and immunohistochemistry respectively and analyzed statistically by image system. The results showed that the number of implantation sites in model group was remarkably less than in normal control group and TCM group. There was no significant difference between normal control group and TCM group. The expression of LIF mRNA and protein in model group was delayed. Bushenantai recipe could increase the expression of LIF mRNA and protein in endometria of mice with EID. It was suggested that Bushenantai recipe could improve embryo implantation of mice with EID by promoting the endometrial LIF expression and endometrial decidualization.

Effect of 935-MHz Phone-simulating Electromagnetic Radiation on Endometrial Glandular Cells during Mouse Embryo Implantation

This study examined the impact of 935MHz phone-simulating electromagnetic radiation on embryo implantation of pregnant mice.Each 7-week-old Kunming (KM) female white mouse was set up with a KM male mouse in a single cage for mating overnight after induction of ovulation.In the first three days of pregnancy,the pregnant mice was exposed to electromagnetic radiation at low-intensity (150 μW/cm2,ranging from 130 to 200 μW/cm2,for 2-or 4-h exposure every day),mid-intensity (570 μW/cm2,ranging from 400 to 700 μW/cm2,for 2-or 4-h exposure every day) or high-intensity (1400 μW/cm2,ranging from 1200 to 1500 μW/cm2,for 2-or 4-h exposure every day),respectively.On the day 4 after gestation (known as the window of murine embryo implantation),the endometrium was collected and the suspension of endometrial glandular cells was made.Laser scanning microscopy was employed to detect the mitochondrial membrane potential and intracellular calcium ion concentration.In high-intensity,2-and 4-h groups,mitochondrial membrane potential of endometrial glandular cells was significantly lower than that in the normal control group (P<0.05).The calcium ion concentration was increased in low-intensity 2-h group but decreased in high-intensity 4-h group as compared with the normal control group (P<0.05).However,no significant difference was found in mitochondrial membrane potential of endometrial glandular cells between low-or mid-intensity groups and the normal control group,indicating stronger intensity of the electromagnetic radiation and longer length of the radiation are required to inflict a remarkable functional and structural damage to mitochondrial membrane.Our data demonstrated that electromagnetic radiation with a 935-MHz phone for 4 h conspicuously decreased mitochondrial membrane potential and lowered the calcium ion concentration of endometrial glandular cells.It is suggested that high-intensity electromagnetic radiation is very likely to induce the death of embryonic cells and decrease the chance of their implantation,thereby posing a high risk to pregnancy.

DS147 Improves Pregnancy in Mice with Embryo Implantation Dysfunction Induced by Controlled Ovarian Stimulation

Summary： The study examined the effect of DS147, the bioactive component of the traditional herbal recipe Bangdeyun, on pregnancy in mice with embryo implantation dysfunction induced by controlled ovarian stimulation （COS）, and the underlying mechanisms. Female mice were superovulated by intrap eritoneal injection of 7.5 IU of pregnant mare serum gonadotropin （PMSG） followed by an additional injection of 7.5 IU hCG 48 h later to establish embryo implantation dysfunction （EID） model. Pregnant mice were randomly divided into normal control group, COS group and DS147-treated groups. The pregnancy rate and the average implantation site were obtained on pregnancy day 8 （PD8）. The side effect of 200 mg/kg of DS147 on naturally pregnant mice was also observed. Further, the uterine and ovarian tissue samples were collected on PD5 for measuring their weights, observing the development of the endometrium and ovary, and detecting the endometrial expression ofMMP-2, TIMP-2, CD34 and angiogenin （ANG）. The female mice treated with DS147 at doses of 100 to 800 mg/kg showed a higher pregnancy rate than those in COS group, and the highest pregnancy rate of 83.3% occurred in the 200 mg/kg DS147-treated group. Moreover, no obvious side effect was found in mice treated with 200 mg/kg DS147 on PD8 and PD16. The ovarian and uterine weights, and the expression levels of MMP-2, ANG and CD34 were significantly increased in DS147-treated groups when compared with COS group. The TIMP-2 expression level was much lower in DS147-treated mice than in COS mice and the ratio of MMP-2/TIMP-2 was much higher in DS147-treated group than in COS group, and even higher than normal control group. In all, these findings suggest that DS147 may improve pregnancy in mice with COS-induced EID by promoting matrix degradation and angiogenesis, and improving the development of corpus luteum and endometrial decidualization around the implantation window.

A Novel Three-Dimensional Mouse Embryonic Implantation Model In Vitro

To regenerate three-dimensional endometrium in vitro as a novel model for studying the mechanism of implantation of embryos, the luminal epithelial cells and stromal cells of the rabbit uterus were separated and cultured in vitro. The type Ⅰ mouse tail collagen was used as scaffolding material. The stromal cells were inoculated in the type I mouse tail collagen, and the luminal epithelial cells were inoculated on the type i mouse tall collagen to regenerate the endometrium in vitro. The regenerated endometrium was cultured in DMEM-F/12 media containing 100 nmol L^-1 progesterone, 10 nM β-estradiol, and 10% fetal bovine serum （FBS） for 3 d. The media were then replaced with CZB containing 100 nM progesterone, 10 nmol L-1 β-estradiol, and 10% FBS, and the mouse blastulas were co-cultured with it. The results of scanning electronic micrography showed that the epithelial cells on the surface of the reconstructed endometrium were covered with numerous slender microvilli and some epithelial cells protruded pinopodes. After culturing for 12 h with the mouse blastula, the shedding, attachment, and implantation of the blastula were observed. The blastula can escape from zona pellucida and attach to the three-dimensional endometrium and is then implanted into it. This study showed that the reconstructed three-dimensional endometrium can serve as a robust embryo implantation model in vitro.

Activation of Uterine Smad3 Pathway Is Crucial for Embryo Implantation

Embryo implantation is a complicated physiological process tightly regulated by multiple biological molecules including growth factors.Transforming growth factor-betas(TGF-βs)and their most specific signal transduction factors,Smads,are expressed in the endometrium during the window of implantation.Recent researches indicated that Smad dependent TGF-β signaling may play an important role in the process of embryo implantation.In this study,we measured the expression of TGF-β1,TGF-β receptor type I(TpRI),Smad3 and p-Smad3 in the endometrium of mice and observed their elevation on day 4,5 and 6 of pseudopregnancy.Then we administrated a specific Smad3 inhibitor(Sis3)into the uterine cavity of mice on day 3 of pregnancy.The results showed a reduction in insulin-like growth factor-1(IGFBP-1)expression and the decreased number of implanted embryo after the administration.In addition,Sis3 was found to reduce the IGFBP-1 secretion in decidualized endometrial stromal cells.Taken all together,our findings demonstrated that TGF-β/Smad3 signaling is involved in the process of embryo implantation.

Down-regulation of Coxsakie and Adenovirus Receptor during Embryo Implantation

In this study,real-time PCR and immunohistochemistry were used to detect coxsakie and adenovirus receptor (CAR) expression.Both localization and quantity were evaluated in the uteri ob-tained at days post coitus (dpc) 2.5,4.5,6.5,8.5.Outcome of PCR was assessed by 2-ΔΔCt method.Im-age Pro-Plus 6.0 software was used for quantifying mean density of CAR expression in immunohisto-chemical sections.We found relatively weak CAR expression in the mouse uteri during implantation window.PCR and immunohistochemistry revealed highest CAR expression was detected on dpc 2.5 followed by down-regulation of CAR at dpc 4.5 and 6.5 (with significant difference).At dpc 8.5,CAR expression was increased slightly again.It is concluded that during implantation,the expression of CAR mRNA and protein is declined,resulting in the impairment of tight junction between cavity epithelium cells.After implantation window closure,CAR appears again to maintain epithelium stability.CAR might play an important role during embryo implantation procedure.

Cysteine dioxygenase and taurine are essential for embryo implantation by involving in E2-ERαand P_(4)-PR signaling in mouse

Background Taurine performs multiple physiological functions,and the maintenance of taurine level for most mammals relies on active uptake from diet and endogenous taurine synthesis through its synthesis enzymes,including cysteine dioxygenase(CDO).In addition,uterus tissue and uterus fluid are rich in to urine,and to urine synthesis is regulated by estrogen(E2)and progesterone(P_(4)),the key hormones priming embryo-uterine crosstalk during embryo implantation,but the functional interactions and mechanisms among which are largely unknown.The present study was thus proposed to identify the effects of CDO and taurine on embryo implantation and related mechanisms by using Cdo knockout(KO)and ovariectomy(OVX)mouse models.Results The uterine CDO expression was assayed from the first day of plugging(d 1)to d 8 and the results showed that CDO expression level increased from d 1 to d 4,followed by a significant decline on d 5 and persisted to d 8,which was highly correlated with serum and uterine taurine levels,and serum P_(4) concentration.Next,Cdo KO mouse was established by CRISPER/Cas9.It was showed that Cdo deletion sharply decreased the taurine levels both in serum and uterus tissue,causing implantation defects and severe subfertility.However,the implantation defects in Cdo KO mice were partly rescued by the taurine supplementation.In addition,Cdo deletion led to a sharp decrease in the expressions of P_(4)receptor(PR)and its responsive genes Ihh,Hoxa10 and Hand2.Although the expression of uterine estrogen receptor(ERa)had no significant change,the levels of ERa induced genes(Muc1,Ltf)during the implantation window were upregulated after Cdo deletion.These accompanied by the suppression of stroma cell proliferation.Meanwhile,E2inhibited CDO expression through ERa and P_(4)upregulated CDO expression through PR.Conclusion The present study firstly demonstrates that taurine and CDO play prominent roles in uterine receptivity and embryo implantation by involving in E2-ERa and P_(4)-PR signaling.These are crucial for our understanding the mechanism of embryo implantation,and infer that taurine is a potential agent for improving reproductive efficiency of livestock industry and reproductive medicine.

Lipopolysaccharide-binding Protein Involved in Process of Mouse Embryo Implantation and Decidualization of Endometrial Stromal Cells

Lipopolysaccharide-binding protein(LBP)functions as an acute phase protein and plays a role in the innate immune response to bacterial challenge.To investigate the uterine expression of LBP during peri-implantation in mice,in situ hybridization and immunohistochemical staining were used to detect the mRNA and protein expression of LBP in mouse uteri in the early pregnancy,pseudopregnancy,artificial decidualization and hormone-treated mice.The results showed that LBP was expressed in uterine luminal epithelium(LE)and glandular epithelium(GE)during days 1-4 of pregnancy.During days 5-8,LBP was weakly expressed in the decidual cells around the embryo on the 5th day of pregnancy(implantation occurred),then gradually increased,LBP was strongly expressed in the decidual zone on the 8th day of pregnancy.The expression of LBP in pseudopregnancy was similar with pregnancy on days 1-4.In artificial decidualization mice,LBP was observed in uterine LE and GE in the control horn,whereas LBP expression was significantly higher in decidua of mouse uteri under artificial decidualization.In hormone-treated mice,the expression of LBP wasup-regulated by 17β-estradiol(E2)and progesterone(P4).In addition,the cultured mouse endometrial stromal cells(mESCs)were induced for in vitro decidualization with 10 nmol·L-1 E2 and 1μmol·L-1 P4.Real-time PCR results showed that LBP mRNA expression was highly induced in mESCs after decidual stimulus.In vivo and in vitro experiments showed that LBP was expressed in the decidual cells,indicating that LBP involved in decidualization of mouse uteri.

Endocannabinoid Signaling in Modulating Periimplantation Events

Cannabinoids have long been suspected associating with abnormal fetal growth and outcome. However, the molecular mechanisms in which they are involved had long been obscure for several decades. Only recently, after the identification of two types of cannabinoid receptors （CB1-R and CB2-R） and the following discoveries of their corresponding endogenous ligands, the mystery behind those seemingly facts began gradually unveiled. Through a series of landmark research, it is now indicated that the endocannabinoid signaling via the ligand-receptor interaction plays an important role in modulating early development of preimplantation embryo and synchronizing embryo development with uterine receptivity for implantation. Current data suggest that the physiological functions their metabolic pathways are potentially very of endocannabinoid signaling as well as exited areas to be explored further. This review will first introduce the reproductive functions of endocannabinoid signaling from epidemiological and molecular background, then focus on its reciprocal interactions between the embryo and maternal tissues, as well as related metabolic aspects in regards to implantation. It is hoped that further investigation of this physiologically fundamental signaling will generate more exciting information elucidating the complexity of implantation thus lead to a better control of human reproduction.

Expression of Prominin-1 in Mouse Uterus During Peri-implantation

To investigate the expression of Prominin-1(Prom-1)in mouse uterus during peri-implantation.In situ hybridization and immunohistochemical staining were used to detect the mRNA and protein expression level of Prom-1 in mice uterus in early pregnancy,pseudopregnancy,estrous cycle,treated with hormone,delayed implantation and activation models.The results showed that Prom-1 was gradually weakened in uterine luminal epithelium(LE)and glandular epithelium(GE)during days 1-4 of pregnancy.During days 5-8,Prom-1 was strongly expressed in GE,and signal of Prom-1 protein was detected in matrix and decidua around the embryo.Similar to pregnancy,Prom-1 was strongly expressed in LE and GE on the 1st day and weakly expressed on the 4th day of pseudopregnancy.In addition,Prom-1 was highly expressed in LE and GE on estrus.Expression of Prom-1 was observed in the LE and the GE of delayed-implantation uterus.In activated-implantation animal model,Prom-1 was strongly expressed in the GE.In the hormone-treated model,Prom-1 expression levels were higher in the uterus of the 17β-estradiol-treated group than those in the control group.These results indicated that Prom-1 might promote the proliferation of mouse endometrial epithelium and participate in the establishment of uterine receptivity.Meanwhile,the expression of Prom-1 was up-regulated by the 17β-estradiol,indicating that Prom-1 might involve in the process of decidua development regulated by uterine glands,and Prom-1 might play an important role in mice early pregnancy.

Transcription and Translation of Dickkopf-1 in Endometrium of Pregnant Mice during the Peri-implantation Period

Summary: To study the expression of Dickkopf-1 (DKK-1) in endometrium of pregnant mice during the peri-implantation period and the role of DKK-1 during the embryo implantation in mice. Immunohistochemical technique was employed to determine the location of DKK-1 protein in endometrium, and semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR) was utilized to determine the levels of DKK-1 mRNA. Our results showed that the expressions of DKK1 mRNA and protein were higher in experimental groups than in control group (P<0.01), and it increased significantly on day 3 and reached its peak on day 4, and then decreased gradually on day 5-7. The levels of DKK-1 mRNA and protein on day 4 was significantly higher than those of other groups (P<0.01). It is concluded that DKK-1 probably plays an important role in signal transudation of embryo implantation and its high expression indicates the opening of implantation window.

Expression of Nuclear Factor-κB in Mouse Uterus during Peri-implantation

To investigate the expression of the subunit p65 of NF-κB and inhibitor kappa B alpha (IκBα) in mouse uterus during peri-implantation, thereby investigating whether transient activation of nuclear factor-κB (NF-κB) takes place during embryo implantation in mice. Immunohistochemical technique was used to examine the expression and localization of p65 in endometrium or deciduas, and Western blot analysis was employed to detect the levels of IκBα protein in mouse endometrium or deciduas. P65 protein was detected in stromal cells, epithelial cells of endometrium as well as in myometrium. Staining was predominately seen in the cytoplasm of the cells. Staining intensity for p65 was stronger in the epithelial compartment than the stromal compartment and myometrium. Staining intensity increased slightly during pregnancy, and it reached a high level on pregnancy day 5 and day 8. In contrast to p65, the level of IκBα protein was lowest on pregnancy day 5 in all groups. Our results suggested that NF-κB may regulate embryo implantation by its transient activation in mice.

Study of Endometrial Receptivity during Implantation in Implantation Dysfunction Mouse

Objective To establish the mice model of implantation dysfunction and to study the endometrial receptivity during implantation in implantation dysfunction mouse. Methods Sexually mature female virgin, Kunming mice were randomly assigned to the control group and the model group postcoitally. The model mice at 9 ： 00 AM on d 4 of pregnancy（d 4） were injected subcutaneously with mifepristone. All animals were sacrificed at 9 ：00 PM on d 4 and their uterine horns were examined for the presence of implanted embryos. Histopathology of uterine endometrium was observed by light-microscope. The endometrial expressions of estrogen receptor （ER） and progesterone receptor （PR） assessed by immunnohistochemical SP method. The endometrial expressions of ER mRNA and PR mRNA were assessed by semi-quantitative reverse transcriptase polymerase chain reaction （RT-PCR）. Results Compared with control group, implantation rates and average embryo num- ber significently decreased in model group, the development of endometrium was inhibited. In model group, absorbency and area rate of ER and PR in the gland and stroma were lower than those in control group （P〈0.05）. Expressions of ER mRNA and PR mRNA in model uterus were significantly lower than those in the control. Conclusion The endometrial receptivity and implantation decreased in mifepristoneinduced implantation dysfunction mouse.

Expression of N-acetyl-glucosamine-6-O-sulfotransferase in the endometrium of implantation window stage from infertile patients

Objective:To observe the expression of N-acetyl-glucosamine-6-O-sulfotransferase(GN-6-ST)in the endometrium during the window stage of implantation from infertile women before IVF-ET treatment,we compared the GN-6-ST gene expression level between the women with succeeded and failed implantation,and investigated the roles of selectin and its ligands in the embryo implantation.Methods:The hysteroscopy and endometrial biopsies were performed in patients prior to undergoing IVF-ET treatment in the IVF Center of the First Affiliated Hospital of Nanjing Medical University from July 2004 to March 2005.Fourteen patients who succeeded in implantation were taken as study group,while the 28 infertile patients with failed implantation served as control group.The RT-PCR method was used to detect the mRNA levels of N-acetyl-glucosamine-6-O-sulfotransferase in the endometrium during the window stage of imp-lantation of the women from both groups.Results:For these infertile patients with succeeded implantation,the average mRNA expression level of acetyl-glucosamine-6-O-sulfotransferase in the endometrium during the window stage of implantation was(0.65±0.33),while for those with failed implantation cycle,the average mRNA expression level was(0.41±0.36),which was significantly lower than that of study group,P<0.05.Conclusions:The combination of the selectin and ligands may play a role in the embryo implantation capacibility.

Stromal cell decidualization and embryo implantation: a vulnerable step leading to successful pregnancy

Endometrial stromal cell decidualization is a crucial step in endometrial remodeling during pregnancy.Decidualization is controlled by orchestrated ovarian hormones,followed by the activation of various downstream signaling pathways.Accumulating evidence has shown multiple functions of decidualized endometrial stromal cells during embryo implantation,including tissue remodeling,antioxidative stress,angiogenesis,and immune tolerance.The distinct secretomes of decidualized stromal cells also reveal their intensive interactions with epithelial,endothelial,and immune cells.However,aberrant decidualization leads to pregnancy failures,such as recurrent pregnancy loss and repeated implantation failure.This review aimed to provide an overview of the molecular mechanisms underlying the divergent functions of decidualized endometrial stromal cells and their potential clinical applications.Moreover,the use of single-cell RNA sequencing data further enhances our understanding of these biological processes.This review discusses decidualization-related signaling pathways that serve as potential therapeutic targets for treating implantation failure in in vitro fertilization and provides novel approaches to investigate the underlying causes of female infertility.