Nucleolar stress regulates stromal-epithelial transition via NPM1 during decidualization.

Embryo implantation and decidualization are crucial steps during early pregnancy. We recently showed that nucleolar stress is involved in embryo implantation. This study was to explore whether nucleolar stress participates in mouse and human decidualization. Our data demonstrated that a low dose of actinomycin D (ActD) could induce nucleolar stress in stroma cells. Nucleolar stress promotes the stromal-epithelial transition during mouse in vitro decidualization through nucleophosmin1 (NPM1). Under nucleolar stress, Wnt family member 4 (Wnt4), a decidualization marker, is significantly increased, but decidua/trophoblast prolactin-related protein (Dtprp/Prl8a2) expression remains unchanged. For translational significance, we also examined the effects of nucleolar stress on human decidualization. Nucleolar stress stimulated by a low dose of ActD enhances human stromal-epithelial transition during human decidualization, but has no effects on the expression of insulin-like growth factor-binding protein 1 (IGFBP1). Our study indicates that nucleolar stress may promote only the mesenchymal-epithelial transition (MET), but not for all the molecular changes during decidualization.

Cyclophilin A plays an important role in embryo implantation through activating Stat3.

Embryo implantation is a crucial step for the successful establishment of mammalian pregnancy. Cyclophilin A (CYPA) is a ubiquitously expressed intracellular protein and is secreted in response to inflammatory stimuli to regulate diverse cellular functions. However, there are currently no reports about the role of CYPA in embryo implantation. Here, we examine the expression pattern of CYPA during mouse early pregnancy and explore the potential role of CYPA during implantation. CYPA is expressed in the subluminal stroma surrounding the implanting blastocyst on day 5 of pregnancy, but not at inter-implantation sites. In ovariectomized mice, estrogen and progesterone significantly stimulate CYPA expression. When pregnant mice are injected intraperitoneally with CYPA inhibitor, the numbers of implantation sites are significantly reduced. Using an in vitro stromal cell culture system, Ppia siRNA knockdown of CYPA and CYPA-specific inhibitor treatment partially inhibits levels of CD147, MMP3 and MMP9. Decreased CYPA expression also significantly inhibits Stat3 activity and expands estrogen responsiveness. Taken together, CYPA may play an important role during mouse embryo implantation.

Nucleolar stress regulation of endometrial receptivity in mouse models and human cell lines.

Embryo implantation is essential to the successful establishment of pregnancy. A previous study has demonstrated that actinomycin D (ActD) could initiate the activation of mouse delayed implantation. However, the mechanism underlying this activation remains to be elucidated. A low dose of ActD is an inducer of nucleolar stress. This study was to examine whether nucleolar stress is involved in embryo implantation. We showed that nucleolar stress occurred when delayed implantation was activated by ActD in mice. ActD treatment also stimulated the Lif-STAT3 pathway. During early pregnancy, nucleolar stress was detected in the luminal epithelial cells during the receptive phase. Blastocyst-derived lactate could induce nucleolar stress in cultured luminal epithelial cells. The inhibition of nucleophosmin1 (NPM1), which was a marker of nucleolar stress, compromised uterine receptivity and decreased the implantation rates in pregnant mice. To translate these mouse data into humans, we examined nucleolar stress in human endometrium. Our data demonstrated that ActD-induced nucleolar stress had positive effects on the embryo attachment by upregulating IL32 expression in non-receptive epithelial cells rather than receptive epithelial cells. Our data should be the first to demonstrate that nucleolar stress is present during early pregnancy and is able to induce embryo implantation in both mice and humans.

[Methyltransferase inhibitor BIX01294 promotes the migration and inhibits decidualization of mouse uterine stromal cells in vitro].

OBJECTIVE: To investigate the effect of BIX01294 (BIX), a methyltransferase inhibitor, on the migration and decidualization of the stromal cells in mouse uterus. METHODS: Mouse endometrial stromal cells were isolated and cultured from the uterus of pregnant mice on day 3.5 of gestation. The migration and decidualization of mouse endometrial stromal cells treated with BIX at different concentrations were observed with wound healing assay and real-time PCR. RESULTS: The migration distance of mouse endometrial stromal cells increased as the BIX concentration increased within the range below 15 µmol/L. Compared with the control cells, the cells treated with BIX (15 µmol/L) showed significantly increased migration distances, but increasing BIX concentration to 20 µmol/L did not further increase the cell migration distance and began to cause cell death. Compared with the control cells, the BIX-treated stromal cells exhibited significantly down-regulated expression of Ehmt2 mRNA, and 15 µmol/L BIX caused inhibition of decidualization in the stromal cells. CONCLUSION: Within a defined concentration range, BIX promotes the migration and inhibits decidualization of mouse uterine stromal cells by inhibiting the expression of Ehmt2 mRNA.

[Expression of FABP7 in mouse placenta tissue and human trophoblast HTR-8/Svneo cells].

OBJECTIVE: To detect the expression of FABP7 in the placenta of pregnant mice and in HTR-8/Svneo cells. METHODS: Real-time PCR and immunofluorescence were used to detect FABP7 mRNA and protein expressions in the uterine and placental tissue of pregnant mice at different days of gestation. FABP7 expression was also detected in cultured HTR-8/Svneo cells using immunofluorescence assay. The mice were treated with E2, P4 or their combination for 6 and 24 h and Fabp7 mRNA level in the uterus was detected with real-time PCR. RESULTS: At 7.5-10.5 days of gestation, the pregnant mice showed positive expressions of Fabp7 mRNA in the uterus and placenta, and FABP7 protein was detected in the decidualized cells and trophoblast giant cells. The expressions of FABP7 were detected at both the mRNA and protein levels in cultured HTR-8/Svneo cells. In mice treated with P4 alone or with E2+P4 for 6 and 24 h, the expression level of Fabp7 mRNA was upregulated in the uterus. Fabp7 upregulation was observed in mice at 24 h following E2 treatment but not at 6 h. CONCLUSION: FABP7 is expressed in trophoblast giant cells and decidual cells in the placental tissue of mice and in cultured HTR-8/Svneo cells, suggesting the involvement of FABP7 in placental development and in maintenance of pregnancy. E2 and P4 can regulate the expression of FABP7 in mouse uterus.

Protective Effects of Curcumin against Sodium Arsenite-induced Ovarian Oxidative Injury in a Mouse Model.

BACKGROUND: Excessive reactive oxygen species (ROS) may lead to a number of reproductive diseases such as polycystic ovary syndrome. This study aimed to establish an animal model of ovarian oxidative stress and to assess the protective effect of curcumin against oxidative injury. METHODS: Ovarian oxidative stress was induced in female Kunming mice (n = 40) with intraperitoneal injection of 8 mg/kg sodium arsenite (As) once every other day for 16 days; meanwhile, they were, respectively, treated by intragastric administration of 0, 100, 150, or 200 mg/kg (n = 10/group) curcumin once per day for 21 days. Ten normal mice were used as control. Then, the mice were injected intraperitoneally with BrdU and sacrificed; the right ovaries were collected for hematoxylin and eosin (HE) staining and BrdU immunohistochemistry, and the left ovaries for enzyme-linked immunosorbent assay (ELISA) and Western blotting analyses. RESULTS: The ELISA results showed that ROS (11.74 ± 0.65 IU/mg in 8 mg/kg AS + 0 mg/kg curcumin group vs. 10.71 ± 0.91 IU/mg in control group, P= 0.021) and malondialdehyde (MDA) (0.32 ± 0.02 nmol/g in 8 mg/kg AS + 0 mg/kg curcumin group vs. 0.27 ± 0.02 nmol/g in control group, P= 0.048) increased while superoxide dismutase (SOD) (3.96 ± 0.36 U/mg in 8 mg/kg AS + 0 mg/kg curcumin group vs. 4.51 ± 0.70 U/mg in control group, P= 0.012) and glutathione peroxidase (17.36 ± 1.63 U/g in 8 mg/kg AS + 0 mg/kg curcumin group vs. 18.92 ± 1.80 U/g in control group, P= 0.045) decreased in the ovary after injection of As, indicating successful modeling of oxidative stress. Curcumin treatment could considerably increase SOD (4.57 ± 0.68, 4.49 ± 0.27, and 4.56 ± 0.25 U/mg in 100 mg/kg, 150 mg/kg, and 200 mg/kg curcumin group, respectively, allP < 0.05) while significantly reduce ROS (10.64 ± 1.38, 10.73 ± 0.71, and 10.67 ± 1.38 IU/mg in 100 mg/kg, 150 mg/kg, and 200 mg/kg curcumin group, respectively, allP < 0.05) and MDA (0.28 ± 0.02, 0.25 ± 0.03, and 0.27 ± 0.04 nmol/g in 100 mg/kg, 150 mg/kg, and 200 mg/kg curcumin group, respectively; bothP < 0.05) in the ovary. HE staining and BrdU immunohistochemistry of the ovarian tissues indicated the increased amount of atretic follicles (5.67 ± 0.81, 5.84 ± 0.98, and 5.72 ± 0.84 in 100 mg/kg, 150 mg/kg, and 200 mg/kg curcumin group, respectively, all P < 0.05), and the inhibited proliferation of granular cells under oxidative stress would be reversed by curcumin. Furthermore, the Western blotting of ovarian tissues showed that the p66Shc expression upregulated under oxidative stress would be lowered by curcumin. CONCLUSION: Curcumin could alleviate arsenic-induced ovarian oxidative injury to a certain extent.

Non-coding RNA LINC00473 mediates decidualization of human endometrial stromal cells in response to cAMP signaling.

Decidualization is an essential step in the establishment of pregnancy. However, the functional contributions of long intergenic noncoding RNAs (LincRNAs) to decidualization have not been explored. To explore the regulation and role of LincRNAs during human decidualization, human endometrial stromal cells (HESCs) are induced to undergo in vitro decidualization by treating with estradiol-17ß, db-cAMP and medroxyprogesterone acetate. LINC00473 (LINC473) expression is highly induced in HESCs after decidual stimulus. We found that cAMP-PKA pathway regulates the expression of LINC473 through IL-11-mediated STAT3 phosphorylation. RNA interference-mediated down-regulation of LINC473 inhibits in vitro decidualization. These results suggested that LINC473 might be functionally required for human decidualization. This is the first report demonstrating the presence of LincRNA during human decidualization.

Effects of androgen on embryo implantation in the mouse delayed-implantation model.

OBJECTIVE: To examine the effects of androgen on implantation and decidualization in the mouse delayed-implantation model. DESIGN: Experimental animal study. SETTING: University research laboratory. ANIMAL(S): Sexually mature female mice (Kunming White strain). INTERVENTION(S): Delayed and activated implantation; pseudopregnancy; embryo transfer (ET); E(2) assay; inhibitor. MAIN OUTCOME MEASURE(S): Effects of androgen on embryo implantation were determined by treating the mice under delayed implantation with different doses of testosterone propionate (TP); the effects of androgen on the expression of implantation-related genes were examined by in situ hybridization. RESULT(S): Delayed implantation could be initiated by TP. Dihydrotestosterone was also able to initiate implantation in the delayed-implantation model. The implantation window could be maintained for at least 48 hours by 5 mg TP per mouse. Prostaglandin endoperoxide synthase 2 (Ptgs2) and microsomal prostaglandin E synthase (mPtges) were aberrantly expressed in mouse uterus at implantation sites after delayed implantation was activated by high doses of TP. CONCLUSION(S): A low dose of TP led to a delay in embryo implantation, but a high dose caused aberrant expression of both Ptgs2 and mPtges at the implantation site. It is possible that high doses of TP may disturb peri-implantation development or may be involved in early pregnancy loss by disturbing the uterine prostaglandin system.

Rat ovulation, implantation and decidualization are severely compromised by COX-2 inhibitors.

Although Cyclooxygenase-2 (COX-2) is essential for mouse ovulation, fertilization, implantation and decidualization, the regulation and function of COX-2 in rat reproduction are still unknown. This study was designed to examine the action of COX-2 in rat ovulation, implantation and decidualization by using two specific inhibitors of COX-2 (nimesulide and niflumic acid). Compared to control, either nimesulide or niflumic acid significantly inhibited the ovulation in the superovulated rats. Although nimesulide had no obvious effects on the number of implantation sites and the vascular permeability, the expression of PPARdelta, HB-EGF and vimentin proteins was down-regulated in the nimesulide-treated groups. COX-1 protein was upregulated by nimesulide treatment. Nimesulide also had an inhibitory effect on decidualization during early pregnancy and under artificial decidualization. Moreover, nimesulide caused the increase of the gestation period and the reduction of litter size and birth weight compared to controls. Based on our data, rat implantation and decidualization were delayed by nimesulide treatment, resulting in the reduction of litter size and birth weight and the prolongation of gestational length, suggesting that COX-2 plays an important role in implantation and decidualization.

Differential expression and regulation of prostaglandin transporter and metabolic enzymes in mouse uterus during blastocyst implantation.

OBJECTIVE: To examine the spatiotemporal expression and regulation of prostaglandin transporter (PGT), 15-hydroxy-PG dehydrogenase (15-PGDH), and carbonyl reductase 1 (CBR1) messenger RNA (mRNA) and protein in the mouse uterus during embryo implantation and in related models. DESIGN: Experimental animal study. SETTING: University research laboratory. ANIMAL(S): Sexually mature female Kunming strain white mice. INTERVENTION(S): Delayed and activated implantation, artificial decidualization, and subcutaneous injection of progesterone (P) and E(2) in ovariectomized mouse. MAIN OUTCOME MEASURE(S): The expression of mRNA and protein were detected by in situ hybridization and immunohistochemistry in mouse uterus. RESULT(S): Prostaglandin transporter mRNA and protein were expressed in the subluminal stroma at implantation site on day 5 of pregnancy and then in decidua but were not detected at the interimplantation sites and in preimplantation or pseudopregnant uterus. The presence of an active blastocyst was required for PGT expression at the implantation site. Both 15-PGDH and CBR1 mRNA were detected in glandular epithelium on day 4 of pregnancies. The expression of 15-PGDH and CBR1 mRNA was also detected in postimplantation embryos. CONCLUSION(S): These data suggest that differentially expressed PGT and 15-PGDH may participate in PG signaling in mouse uterus during implantation and decidualization.

Global analysis of differential luminal epithelial gene expression at mouse implantation sites.

Although implantation types differ between species, the interaction between blastocyst trophectoderm and apical surface of the uterine epithelium is a common event during the implantation process. In this study, uterine luminal epithelium at implantation and inter-implantation sites was isolated by enzymatic digestion and used for microarray analysis. In a mouse microarray containing 12 345 unigenes, we found 136 genes upregulated more than twofold at the implantation site, while 223 genes were downregulated by at least twofold. Reverse transcription-PCR was used to verify the differential expression of seven upregulated and six downregulated genes chosen randomly from our microarray analysis, and the expression trends were similar. The differential expression patterns of eight upregulated genes were verified by in situ hybridization. Compared with the inter-implantation site on day 5 of pregnancy and the uterus on day 5 of pseudopregnancy, protease, serine, 12 neurotrypsin, endothelin-1, gamma-glutamyl hydrolase, Ras homolog gene family, member U, T-cell immunoglobulin, and mucin domain containing 2, proline-serine-threonine phosphatase-interacting protein 2, 3-monooxgenase/tryptophan 5-monooxgenase activation protein, gamma-polypeptide, and cysteine-rich protein 61 (Cyr61) were upregulated in the luminal epithelium at implantation site on day 5 of pregnancy. These genes may be related to embryo apposition and adhesion during embryo implantation. Cyr61, a gene upregulated at the implantation site, was chosen to examine its expression and regulation during the periimplantation period by in situ hybridization. Cyr61 mRNA was specifically localized in the luminal epithelium surrounding the implanting blastocyst at day 4 midnight and on day 5 of pregnancy, and in the activated uterus, but not expressed in inter-implantation sites and under delayed implantation, suggesting a role for Cyr61 in mediating embryonic-uterine dialog during embryo attachment. Our data could be a valuable source for future study on embryo implantation.

Differential expression and regulation of prostaglandin E synthases in the mouse ovary during sexual maturation and luteal development.

Prostaglandin (PGE) 2 is the most common prostanoid and plays an important role in female reproduction. The aim of this study was to examine the expression and regulation of microsomal (m) PGE synthase (PGES)-1 and cytosolic (c) PGES in the mouse ovary during sexual maturation, gonadotropin treatment and luteal development by in situ hybridization and immunohistochemistry. Both mPGES-1 mRNA signals and immunostaining were localized in the granulosa cells, but not in the thecal cells and oocytes. cPGES mRNA signals were localized in both granulosa cells and oocytes, whereas cPGES immunostaining was exclusively localized in the oocytes. In our superovulated model of immature mice, there was a basal level of mPGES-1 mRNA signals in the granulosa cells at 48 h after equine chorionic gonadotropin (eCG) treatment. mPGES-1 mRNA level was induced by human chorionic gonadotropin (hCG) treatment for 0.5 h, whereas mPGES-1 immunostaining was slightly induced at 0.5 h after hCG treatment and reached a maximal level at 3 h after hCG treatment. eCG treatment had no obvious effects on either cPGES mRNA signals or immunostaining. A strong level of cPGES immunostaining was present in both unstimulated and eCG-treated groups. Both mPGES-1 mRNA signals and immunostaining were highly detected in the corpus luteum 2 days post-hCG injection and declined from days 3 to 7 post-hCG injection. cPGES immunostaining was at a basal level or not detectable from days 1 to 7 after hCG injection and was highly expressed in the corpus luteum from days 9 to 15 post-hCG injection. PGE2 biosynthesized through the mPGES-1 pathway may be important for follicular development, ovulation and luteal formation.

Differential expression and regulation of cylooxygenases, prostaglandin E synthases and prostacyclin synthase in rat uterus during the peri-implantation period.

It has been shown that both prostaglandin I2 (PGI2) and PGE2 are essential for mouse implantation, whereas only PGE2 is required for hamster implantation. To date, the expression and regulation of cyclooxygenase (COX) and prostaglandin E synthase (PGES), which are responsible for PGE2 production, have not been reported in the rat. The aim of this study was to examine the expression pattern and regulation of COX-1, COX-2, membrane-associated PGES-1 (mPGES-1), mPGES-2 and cytosolic PGES (cPGES) in rat uterus during early pregnancy and pseudopregnancy, and under delayed implantation. At implantation site on day 6 of pregnancy, COX-1 immunostaining was highly visible in the luminal epithelium, and COX-2 immunostaining was clearly observed in the subluminal stroma. Both mPGES-1 mRNA and protein were only observed in the subluminal stroma surrounding the implanting blastocyst at the implantation site on day 6 of pregancy , but were not seen in the inter-implantation site on day 6 of pregnancy and on day 6 of pseudopregnancy. Our data suggest that the presence of an active blastocyst is required for mPGES-1 expression at the implantation site. When pregnant rats on day 5 were treated with nimesulide for 24 h, mPGES-1 protein expression was completely inhibited. cPGES immunostaining was clearly observed in the luminal epithelium and subluminal stromal cells immediately surrounding the implanting blastocyst on day 6 of pregnancy. mPGES-2 immunostaining was clearly seen in the luminal epithelium at the implantation site. Additionally, immunostaining for prostaglandin I synthase (PGIS) was also strongly detected at the implantation site. In conclusion, our results indicate that PGE2 and PGI2 should have a very important role in rat implantation.

Cyclooxygenases and prostaglandin E synthases in preimplantation mouse embryos.

Prostaglandin E2 (PGE2) is shown to be essential for female reproduction. Cyclooxygenase (COX) is a rate-limiting enzyme in prostaglandin synthesis from arachidonic acid and exists in two isoforms: COX-1 and COX-2. Prostaglandin E synthase (PGES) is a terminal prostanoid synthase and can catalyse the isomerization of the COX product PGH2 to PGE2, including microsomal PGES-1 (mPGES-1), cytosolic PGES (cPGES) and mPGES-2. This study examined the protein expression of COX-1, COX-2, mPGES-1, cPGES and mPGES-2 in preimplantation mouse embryos by immunohistochemistry. Embryos at different stages collected from oviducts or uteri were transferred into a flushed oviduct of non-pregnant mice. The oviducts containing embryos were paraffin-embedded and processed for immunostaining. COX-1 immunostaining was at a basal level in zygotes and a low level at the 2-cell stage, reaching a high level from the 4-cell to blastocyst stage. COX-2 immunostaining was at a low level at the zygote stage and was maintained at a high level from the 2-cell to blastocyst stages. A low level of mPGES-1 immunostaining was observed from the zygote to 8-cell stages. The signal for mPGES-1 immunostaining became stronger at the morula stage and was strongly seen at the blastocyst stage. cPGES immunostaining was strongly observed in zygotes, 2-cell and 8-cell embryos. There was a slight decrease in cPGES immunostaining at the 4-cell, morula and blastocyst stages. mPGES-2 immunostaining was at a low level from the zygote to morula stages and at a high level at the blastocyst stage. We found that the COX-1, COX-2, mPGES-1, cPGES and mPGES-2 protein signals were all at a high level at the blastocyst stage. PGE2 produced during the preimplantation development may play roles during embryo transport and implantation.

Signal transducer and activator of transcription 3 (Stat3) expression and activation in rat uterus during early pregnancy.

Signal transducer and activator of transcription 3 (Stat3), a member of the Stat family, is specifically activated during mouse embryo implantation. The aim of this study was to investigate the expression, activation and regulation of Stat3 in rat uterus during early pregnancy, pseudopregnancy, delayed implantation and artificial decidualization. Stat3 mRNA was highly expressed in the luminal epithelium on day 5 and in the luminal epithelium and underlying stromal cells at implantation sites on day 6 of pregnancy. There was a strong level of Stat3 protein expression and phosphorylation in the stromal cells near the lumen and in the luminal epithelium on day 5 of pregnancy, which was similar to day 5 of pseudopregnancy. In the afternoon of day 6, the strong level of Stat3 phosphorylation was detected only in the luminal epithelium. Stat3 was highly expressed and activated in the decidual cells from days 7 to 9 of pregnancy and under artificial decidualization in the present study. Our results suggest that the strong level of Stat3 activation in the luminal epithelium and underlying stromal cells during the pre-implantation period may be important for establishing uterine receptivity as in mice, and the high level of Stat3 expression and activation in decidual cells may play a role during decidualization.

Differential expression and activation of Stat3 during mouse embryo implantation and decidualization.

Signal transducer and activator of transcription (STATs) can be activated by many cytokines and growth factors. Stat3, a member of STAT family, is essential for embryonic development. Stat3 is specifically activated during mouse embryo implantation. This study was to investigate the expression, activation, and regulation of Stat3 in mouse uterus during early pregnancy, pseudopregnancy, delayed implantation, artificial decidualization, and hormonal treatments using in situ hybridization and immunohistochemistry. There was a strong level of Stat3 phosphorylation in the luminal epithelium only at the midnight of day 4 pregnancy, which coincides with attachment reaction between the blastocyst and luminal epithelium. However, there was no detectable Stat3 phosphorylation at the corresponding period during pseudopregnancy. On day 5 of pregnancy, Stat3 phosphorylation was strongly observed in the luminal epithelium and the stroma surrounding the implanting blastocyst at implantation sites, but not at the inter-implantation sites. Stat3 phosphorylation was also not detected on day 5 of pseudopregnancy. Stat3 phosphorylation was at a high level in the decidual cells on days 6-8 of pregnancy. Under artificial decidualization, Stat3 was also phosphorylated in the decidual cells. In the ovariectomized mice, there was no Stat3 expression and activation in the uterus. Progesterone had no obvious effects. However, Stat3 mRNA expression and phosphorylation were significantly stimulated by estrogen treatment. Our data suggest that Stat3 phosphorylation may be important for mouse embryo implantation and decidualization, and may also be regulated by maternal estrogen.

Cyclooxygenases and prostaglandin E synthases in the endometrium of the rhesus monkey during the menstrual cycle.

Cyclooxygenase (COX), a rate-limiting enzyme that produces prostaglandins (PGs) from arachidonic acid, exists in two isoforms, COX-1 and COX-2. PGE2 synthase (PGES) is a terminal prostanoid synthase and can enzymatically convert the cyclooxygenase product PGH2 to PGE2, including two isoforms: microsomal PGES (mPGES) and cytosolic PGES (cPGES). cPGES is predominantly linked with COX-1 to promote the immediate response. mPGES is preferentially coupled with the inducible COX-2 to promote delayed PGE2 generation. COX-2-deficient female mice are infertile with abnormalities in ovulation, fertilization, implantation and decidualization. The aim of this study was to examine immunohistochemically the expression pattern of COX-1, COX-2, mPGES and cPGES proteins in the endometrium of the rhesus monkey during the menstrual cycle. COX-1 immunostaining was mainly localized in the luminal epithelium and glandular epithelium near the lumen, and detected in all the stages during the menstrual cycle. COX-2 immunostaining was mainly localized in the luminal and glandular epithelium, and strongly shown during the mid-luteal phase (days 16 and 20) of the menstrual cycle. There was a strong cPGES immunostaining in the luminal and glandular epithelium on days 12, 16, 20 and 25 of the menstrual cycle. mPGES immunostaining was strongly detected in the glandular epithelium on days 20 and 25 of the menstrual cycle. These data suggest that the coupling of cPGES and COX-1 in the luminal epithelium may be responsible for the synthesis of PGE2 in monkey endometrium, and the coupling of mPGES and COX-2 in the glandular epithelium may be of importance for preparing the receptive endometrium.

Calcitonin immunostaining in monkey uterus during menstrual cycle and early pregnancy.

Calcitonin has been shown to be a progesterone-regulated potential marker of the receptive endometrium in the rat and human. The present study was undertaken to immunohistochemically investigate the changes in calcitonin in the monkey uterus during the menstrual cycle and periimplantation period. Calcitonin immunostaining was primarily localized in the glandular epithelium on d 16, 20, and 25 of the menstrual cycle. During early pregnancy, calcitonin immunostaining was strongly observed in the glandular epithelium only on d 9 of pregnancy, the day before implantation. Since the high level of calcitonin immunostaining in the glandular epithelium during the luteal phase of the menstrual cycle and periimplantation period matched the high level of maternal progesterone during this period, the expression of calcitonin in monkey endometrium may be under the regulation of maternal progesterone.