BACKGROUND: The sirtuin family is well recognized for its crucial involvement in various cellular processes. Nevertheless, studies on its role in the human endometrium are limited. This study aimed to explore the expression and localization of the sirtuin family in the human endometrium, focusing on sirtuin 3 (SIRT3) and its potential role in the oxidative imbalance of the endometrium in polycystic ovary syndrome (PCOS). METHODS: Endometrial specimens were collected from both patients with PCOS and controls undergoing hysteroscopy at the Center for Reproductive Medicine, Peking University Third Hospital, from July to August 2015 and used for cell culture. The protective effects of SIRT3 were investigated, and the mechanism of SIRT3 in improving endometrial receptivity of patients with PCOS was determined using various techniques, including cellular bioenergetic analysis, small interfering ribonucleic acid (siRNA) silencing, real-time quantitative polymerase chain reaction, Western blot, immunofluorescence, immunohistochemistry, and flow cytometry analysis. RESULTS: The sirtuin family was widely expressed in the human endometrium, with SIRT3 showing a significant increase in expression in patients with PCOS compared with controls ( P <0.05), as confirmed by protein and gene assays. Concurrently, endometrial antioxidant levels were elevated, while mitochondrial respiratory capacity was reduced, in patients with PCOS ( P <0.05). An endometrial oxidative stress (OS) model revealed that the downregulation of SIRT3 impaired the growth and proliferation status of endometrial cells and reduced their receptivity to day 4 mouse embryos. The results suggested that SIRT3 might be crucial in maintaining normal cellular state by regulating antioxidants, cell proliferation, and apoptosis, thereby contributing to enhanced endometrial receptivity. CONCLUSIONS Our findings proposed a significant role of SIRT3 in improving endometrial receptivity in patients with PCOS by alleviating OS and regulating the balance between cell proliferation and apoptosis. Therefore, SIRT3 could be a promising target for predicting and improving endometrial receptivity in this patient population.
Humans ; Female ; Polycystic Ovary Syndrome/metabolism* ; Endometrium/metabolism* ; Sirtuin 3/genetics* ; Oxidative Stress/genetics* ; Adult ; Animals ; Mice ; Apoptosis/physiology* ; Immunohistochemistry ; Cell Proliferation/physiology*

The onset of pregnancy is marked by the formation of a zygote, while the culmination of gestation is manifested by the delivery of a fetus. Meanwhile, a successful pregnancy entails a meticulously coordinated sequence of events from embryo implantation to sustained decidualization of the uterus to placental development and childbirth. The decidual reaction, a pivotal process occurring within the endometrium during pregnancy, is finely regulated by sex steroids and cytokines. Notably, fibroblast growth factors (FGFs), particularly FGF2, play a critical role in this physiological cascade. Dysregulated FGF expression may trigger inadequate decidualization, precipitating a spectrum of adverse pregnancy outcomes, including preeclampsia, recurrent implantation failure, and miscarriage. Furthermore, the human decidua, distinct from most mammalian species and similar to great apes, undergoes regular cycles of formation and shedding, independent of the presence of the embryo in the endometrium. This process is also tightly controlled by various FGFs. In this review, we comprehensively compare diverse research decidualization models, delineate the trend of endometrial FGFs during the menstrual cycle, and provide a synopsis of endometrial diseases triggered by FGF dysregulation.
Humans ; Female ; Pregnancy ; Decidua/physiology* ; Animals ; Endometrium/physiology* ; Fibroblast Growth Factors/metabolism* ; Embryo Implantation ; Menstrual Cycle/physiology*

Embryo implantation involves a complex interaction between the embryo and the endometrium of the mother, the study of which faces a variety of problems. The modeling of endometrial epithelial organoids and endometrial assembloids provides a new way to study the process of embryo implantation in vitro. This paper summarized the latest research progress in embryo implantation, the regulation mechanism of endometrial receptivity by estrogen- progesterone coordination and embryo-derived signals, the establishment of endometrial organoids, and the development and application of endometrial assembloids in the research on mother-embryo interaction, providing new strategies for studying the communication between embryo and maternal uterus during implantation.
Endometrium/physiology* ; Organoids/cytology* ; Embryo Implantation/physiology* ; Female ; Animals ; Progesterone/pharmacology* ; Pregnancy ; Estrogens/metabolism* ; Humans

Endometrial receptivity has become the main cause of fertilization and pregnancy outcomes in infertile patients,bringing large psychological damage and economic loss to the patients and their family. In recent years,the role of non-coding RNA has increasingly been recognized. The relationship between non-coding RNA and endometrial receptivity is reviewed in this article.
Embryo Implantation ; Endometrium ; physiology ; Female ; Fertilization in Vitro ; Humans ; Pregnancy ; Pregnancy Outcome ; RNA, Untranslated ; genetics

OBJECTIVE: To observe the repairing effects of estrogen and wheat-grain moxibustion on thin-type endometrium in rats and to explore its possible mechanism. METHODS: Forty healthy SPF-grade adult female SD rats were randomly divided into a normal group, a model group, an estrogen group and a moxibustion group according to random number table method, 10 rats in each group. The model of thin-type endometrium was established during estrous period in all the groups except for the normal group. No intervention was given in the normal group. The intragastric administration of 2 mL of 0.9% sodium chloride solution was applied the next day after modeling in the model group. The intragastric administration of 2 mL of estradiol was given the next day after modeling in the estrogen group. The wheat-grain moxibustion was given at "Guanyuan" (CV 4) and "Shenshu" (BL 23) the next day after modeling in the moxibustion group, 7 moxa cones for each acupoint. The treatment in 3 groups was given once a day. After three estrous cycles, the samples were collected during estrous period; the thickness and morphology of endometrium were observed by HE staining; the expressions of vimentin, keratin and vascular endothelial growth factor (VEGF) in endometrium tissue were detected by immunohistochemistry; the expressions of HOXA10 and LIF in endometrium tissue were detected by Western blot. RESULTS: The endometrial thickness in the model group was significantly thinner than that in the normal group (<0.01); compared with the model group, the endometrial thickness in the estrogen group and the moxibustion group were increased significantly (<0.05, <0.01); the endometrial thickness in the moxibustion group was insignificantly higher than that in the estrogen group (>0.05). The expressions of keratin, vimentin and VEGF in endometrium in the model group were significantly lower than those in the normal group (<0.01); compared with the model group, the expressions of keratin, vimentin and VEGF in endometrium in the estrogen group and the moxibustion group were significantly increased (<0.01). The expressions of keratin, vimentin and VEGF in the moxibustion group were insignificantly higher than those in the estrogen group (>0.05). The expressions of HOXA10 and LIF in endometrium in the model group were significantly lower than those in the normal group (<0.01); compared with the model group, the expressions of HOXA10 and LIF in endometrium in the estrogen group and moxibustion group were significantly increased (<0.05). CONCLUSION The wheat-grain moxibustion could up-regulate the expressions of keratin, vimentin and VEGF in endometrium to improve the endometrial thickness; in addition, it could increase the levels of factors related to endometrial receptivity including HOXA10, LIF, which improves endometrial receptivity and play a repair role.
Animals ; Endometrium ; physiology ; Female ; Moxibustion ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Triticum ; Vascular Endothelial Growth Factor A

Stem cells are undifferentiated cells capable of self-renewal and differentiation into various cell lineages. Stem cells are responsible for the development of organs and regeneration of damaged tissues. The highly regenerative nature of the human endometrium during reproductive age suggests that stem cells play a critical role in endometrial physiology. Bone marrow-derived cells migrate to the uterus and participate in the healing and restoration of functionally or structurally damaged endometrium. This review summarizes recent research into the potential therapeutic effects of bone marrow-derived stem cells in conditions involving endometrial impairment.
Bone Marrow ; Cell Lineage ; Endometrium* ; Female ; Humans ; Physiology ; Regeneration* ; Stem Cells* ; Therapeutic Uses ; Uterus

BACKGROUNDAt present, a diagnostic tool with high specificity for impaired endometrial receptivity, which may lead to implantation failure, remains to be developed. We aimed to assess the different endometrial microRNA (miRNA) signatures for impaired endometrial receptivity by microarray analysis.

METHODSA total of 12 repeated implantation failure (RIF) patients and 10 infertile patients, who conceived and delivered after one embryo transfer attempt, were recruited as RIF and control groups, respectively. Endometrial specimens from the window of implantation (WOI) were collected from these two groups. MiRNA microarray was conducted on seven and five samples from the RIF and control groups, respectively. Comparative, functional, and network analyses were performed for the microarray results. Quantitative real-time polymerase chain reaction (PCR) was performed on other samples to validate the expression of specific miRNAs.

RESULTSCompared with those in the control group, the expression levels of 105 miRNAs in the RIF group were found to be significantly up- or down-regulated (at least 2-fold) by microarray analysis. The most relevant miRNA functional sets of these dysregulated miRNAs were miR-30 family, human embryonic stem cell regulation, epithelial-mesenchymal transition, and miRNA tumor suppressors by tool for annotations of microRNA analysis. Network regulatory analysis found 176 miRNA-mRNA interactions, and the top 3 core miRNAs were has-miR-4668-5p, has-miR-429, and has-miR-5088. Expression levels of the 18 selected miRNAs in new samples by real-time PCR were found to be regulated with the same trend, as the result of microarray analysis.

CONCLUSIONSThere is a significant different expression of certain miRNAs in the WOI endometrium for RIF patients. These miRNAs may contribute to impaired endometrial receptivity.

Adult ; Embryo Implantation ; genetics ; physiology ; Endometrium ; metabolism ; Female ; Humans ; Infertility, Female ; genetics ; MicroRNAs ; genetics ; Microarray Analysis ; Pregnancy ; Real-Time Polymerase Chain Reaction

OBJECTIVETo investigate the role of endometrial macrophages in embryo implantation and in regulating the expression of vascular endothelial growth factor A (VEGFA) in mouse endometrium during the peri-implantation period.

METHODAt D3.5 (D0.5 defined as the morning when a vaginal plug was observed), pregnant mice were divided randomly into experimental group, control group and blank group. In the experimental group, the mice were subjected to intrauterine injection of clodronate liposomes on the left side of uterus to eliminate the macrophages, and PBS liposomes on the right side. PBS liposomes and PBS were administered in the control and blank groups, respectively. The uterine tissues were collected on D5.5 and stained with trypan blue to show the implantation sites. Flow cytometry was performed to examine the percentage of F4/80(+) CD11b(+) macrophages macrophages in the uterus. F4/80(+) macrophage population within the endometrium and ovary and changes in VEGFA expression at the implantation and non-implantation sites were examined using immunohistochemistry.

RESULTSEndometrial F4/80(+) CD11b(+) macrophages macrophages were significantly reduced by 74% following intrauterine injection of clodronate liposomes (P<0.05). The number of macrophages in the ovaries showed no significant difference among the 3 groups. In the experimental group, the left side of the uterine showed imcomplete cavity closure with a lower number of implantation site than the right side (2.20∓1.81 vs 5.10∓1.91, P<0.05). VEGFA expression at the implantation site were significantly decreased in the endometrium on the left side with macrophage suppression as compared with that on the right side (P<0.05).

CONCLUSIONEndometrial macrophages appear to modulate uterine receptivity by regulating the expression of VEGFA to affect embryo implantation, suggesting the important role of macrophages in embryo implantation.

Animals ; Embryo Implantation ; Endometrium ; physiology ; Female ; Immunohistochemistry ; Macrophages ; cytology ; Mice ; Ovary ; cytology ; Pregnancy ; Random Allocation ; Uterus ; cytology ; Vascular Endothelial Growth Factor A ; physiology

Tight junctions (TJs) form continuous intercellular contacts in intercellular junctions. TJs involve integral proteins such as occludin (OCLN) and claudins (CLDNs) as well as peripheral proteins such as zona occludens-1 (ZO-1) and junctional adhesion molecules (JAMs). TJs control paracellular transportation across cell-to-cell junctions. Although TJs have been studied for several decades, comparison of the transcriptional-translational levels of these molecules in canine organs has not yet been performed. In this study, we examined uterine expression of CLDNs, OCLN, junction adhesion molecule-A, and ZO-1 in canine. Expression levels of canine uterine TJ proteins, including CLDN1, 2, 4, 5, JAM-A, ZO-1, and OCLN, were measured using reverse transcription PCR, real-time PCR, and Western blotting, whereas TJs distribution was determined by immunohistochemistry. The mRNA and protein expression levels of OCLN, CLDN-1, 4, JAM-1, and ZO-1 were identified in the uterus. Immunohistochemistry demonstrated that TJs were localized to the endometrium and/or myometrium of the uterus. Our results show that canine TJ proteins, including CLDNs, OCLN, JAM-A, and ZO-1, were expressed in the canine uterus. Taken together, these proteins may perform unique physiological roles in the uterus. Therefore, these findings may serve as a basis for further studies on TJ proteins and their roles in the physiological or pathological condition of the canine uterus.
Animals ; Blotting, Western ; Claudins ; Dogs ; Endometrium ; Female ; Herpes Zoster ; Immunohistochemistry ; Intercellular Junctions ; Junctional Adhesion Molecules ; Mice ; Myometrium ; Occludin ; Physiology ; Polymerase Chain Reaction ; Real-Time Polymerase Chain Reaction ; Reverse Transcription ; RNA, Messenger ; Tight Junctions* ; Transportation ; Uterus*

The aim of this study was to investigate the effect of Bu-Shen-An-Tai recipe (BSATR) and its two components (Bushen recipe, and Huoxue recipe) on endometrial morphology during peri-implantation in superovulated mice. Mice were randomly divided into five groups, including the normal (N), model (M), Bushen (BS), Huoxue (HX) and Bu-Shen-An-Tai (BH) groups. The uteri were collected on day 4 of pregnancy, and the endometrium thickness, microvessel density (MVD) and number of pinopodes observed. Compared with the M group, the endometrial thickness in the BS, HX and BH groups was significantly increased and there was a significant difference in endometrial thickness between the BS and the BH groups. The mean MVD was significantly lower in the M group than in the N group, and there was a significant increase in MVD in the BS, HX and BH groups as compared with the M group. Compared with the M group, the pinopode scores in the endometrium were significantly increased in the HX and BH groups; and the BS group had significantly higher pinipode scores than the HX and BH groups. In conclusion, the results of the present study demonstrated that the recipes (Bushen, Huoxue and BSATR) could improve the endometrial environment by regulating the endometrial thickness, MVD and the number of pinopodes at the window of implantation. Moreover, the Huoxue recipe and the BSATR were more efficient than the Bushen recipe, with the BSATR tending to have the most beneficial effects.
Animals ; Antigens, CD34 ; metabolism ; Drugs, Chinese Herbal ; chemistry ; pharmacology ; Embryo Implantation ; physiology ; Endometrium ; drug effects ; physiology ; ultrastructure ; Female ; Immunohistochemistry ; Mice ; Microscopy, Electron, Scanning ; Microvessels ; metabolism ; physiology ; Ovulation ; physiology ; Pregnancy ; Random Allocation ; Time Factors