Intraovarianism is represented by greater follicle activity in right ovary (RO) than left ovary (LO) during the two or three follicular waves per interovulatory interval in heifers and the ovulatory wave in women. In each species, selection between the dominant follicle (DF or F1) and future largest subordinate follicle (F2) is manifested by diameter deviation. The RO has more ≥6 mm predeviation follicles in heifers, more 2–10 mm predeviation follicles in women, and greater frequency of ovulation in each species. The RO propensity for ovulation likely develops before birth or at least before sexual maturity as indicated by (1) heavier RO with more follicles in recently born calves and heavier right fetal gonad with more DNA content in humans and (2) greater RO frequency for largest follicle of a wave in sexually immature heifers and for first ovulation of puberty. In heifers, intraovarianism is also expressed by (1) two-way enhancement effect between DF and corpus luteum (CL) when in same ovary, (2) regression of predeviation follicles when adjacent to the regressing CL, (3) more frequent location of F2 during predeviation in ovary that contains F1, (4) greater diameter increase during recovery of subordinate follicles when in RO with the future DF, and (5) effect of an intraovarian pattern on the pattern in the next wave. The nature of these forms of intraovarianism is not known but may be physical rather than from local passage of factors between structures. Intraovarianism should be considered when studying systemic hormonal effects on ovarian dynamics.

Summary sentence

An intraovarian system of physical mechanisms affects follicle and luteal dynamics in heifers and women.

Anti-androgenic endocrine-disrupting chemicals (EDCs) can cross the placenta to modify early offspring sexual dimorphic markers. These changes are linked to anogenital distance (AGD), which is an androgen-sensitive anthropometric parameter used as a biomarker of perineal growth and caudal migration of the genital tubercle. This review aimed to summarize strength of evidence for associations of in utero exposure to EDCs with AGD and to identify gaps and limitations in the literature so as to inform future research. We performed an electronic search of English literature in September 2019 in medical literature analysis and retrieval system online (MEDLINE), Web of Science and Toxline. We included epidemiological studies that examined in utero exposure to persistent and nonpersistent EDCs and considered AGD in offspring as an outcome. Our review contained 16 investigations examining exposure to persistent EDCs (nine studies) and nonpersistent EDCs (seven studies). Some individual studies reported an inverse association between exposure to bisphenol A (BPA), dioxins, perfluoroalkyl substances, and organochlorides and AGD in both male and female offspring. Meta-analysis of three studies found a small reduction of AGD in female offspring exposed to BPA. The number of studies per chemical is small, and number of subjects examined is limited; so, replication of these results is needed. To achieve more specificity and better replication of results, future studies should establish the association of nonpersistent EDCs using multiple urine samples, evaluate the cumulative impact of exposure to a mixture of anti-androgenic chemicals, and offer adequate consideration of more maternal- and children-related confounding factors.

Summary sentence

Early-life exposure to anti-androgenic endocrine disrupting chemicals provide inconsistent findings demonstrating an inverse association between higher maternal levels of some chemicals and anogenital distance, the effect being more common in male offspring.

The objective was to identify the transcriptomic profile of in vitro-derived embryos with high competence to establish and maintain gestation. Embryos produced with X-sorted sperm were cultured from day 5 to day 7 in serum-free medium containing 10 ng/ml recombinant bovine colony-stimulating factor 2 (CSF2) or vehicle. The CSF2 was administered because this molecule can increase blastocyst competence for survival after embryo transfer. Blastocysts were harvested on day 7 of culture and manually bisected. One demi-embryo from a single blastocyst was transferred into a synchronized recipient and the other half was used for RNA-seq analysis. Using P < 0.01 and a fold change >2-fold or <0.5 fold as cutoffs, there were 617 differentially expressed genes (DEG) between embryos that survived to day 30 of gestation vs those that did not, 470 DEG between embryos that survived to day 60 and those that did not, 432 DEG between embryos that maintained pregnancy from day 30 to day 60 vs those where pregnancy failed after day 30, and 635 DEG regulated by CSF2. Pathways and ontologies in which DEG were overrepresented included many related to cellular responses to stress and cell survival. It was concluded that gene expression in the blastocyst is different between embryos that are competent to establish and maintain pregnancy vs those that are not. The relationship between expression of genes related to cell stress and subsequent embryonic survival probably reflects cellular perturbations caused by embryonic development taking place in the artificial environment associated with cell culture.

Summary Sentence

Embryos produced in vitro that are capable of maintaining gestation have a gene expression pattern that diverges from embryos that fail to establish pregnancy.

Stanniocalcin-1 (STC-1) is a pro-survival factor that protects tissues against stressors, such as hypoxia and inflammation. STC-1 is co-expressed with the endometrial receptivity markers, and recently endometrial STC-1 was reported to be dysregulated in endometriosis, a condition linked with endometrial progesterone resistance and inflammation. These features are also common in the endometrium in women with polycystic ovary syndrome (PCOS), the most common endocrine disorder in women. Given that women with PCOS present with subfertility, pregnancy complications, and increased risk for endometrial cancer, we investigated endometrial STC-1 expression in affected women. Endometrial biopsy samples were obtained from women with PCOS and controls, including samples from overweight/obese women with PCOS before and after a 3-month lifestyle intervention. A total of 98 PCOS and 85 control samples were used in immunohistochemistry, reverse-transcription polymerase chain reaction, or in vitro cell culture. STC-1 expression was analyzed at different cycle phases and in endometrial stromal cells (eSCs) after steroid hormone exposure. The eSCs were also challenged with 8-bromo-cAMP and hypoxia for STC-1 expression. The findings indicate that STC-1 expression is not steroid hormone mediated although secretory-phase STC-1 expression was blunted in PCOS. Lower expression seems to be related to attenuated STC-1 response to stressors in PCOS eSCs, shown as downregulation of protein kinase A activity. The 3-month lifestyle intervention did not restore STC-1 expression in PCOS endometrium. More studies are warranted to further elucidate the mechanisms behind the altered endometrial STC-1 expression and rescue mechanism in the PCOS endometrium.

Summary sentence

Endometrial expression of STC-1 in the secretory phase is blunted in women with PCOS, suggesting impaired protection against stress.

Initiation of luteolysis in ruminants is variable due to ill-defined mechanisms. Cycles of two follicular waves are shorter and have earlier luteolysis than three-wave cycles. This study validated a cytobrush technique for evaluating dynamics of endometrial gene expression and associated changes in mRNA with timing of luteolysis, based on circulating progesterone and ultrasound-determined changes in blood flow and volume of corpus luteum (CL). On day 8 (ovulation = day 0), Holstein heifers were randomized into two groups: cytobrush group (n = 9) had an endometrial sample collected every 48 h from day 8 until end of luteolysis (CL blood flow ≤ 20%) and control group was sampled only once either before (day 12; n = 4) or at the end of luteolysis (n = 5). Concentrations of progesterone, CL blood flow, CL volume, and the frequency of two and three-wave cycles were similar between groups. Endometrial mRNA for progesterone receptors and estradiol receptors 1 and 2 was greater on day 8 and decreased thereafter similarly in two and three-wave cycles. Oxytocin receptor mRNA increased earlier in two vs three-wave cycles (day 14 vs 18), and the increase was associated with the onset of luteolysis. In conclusion, the cytobrush technique allowed in vivo collection of multiple endometrial samples during the estrous cycle. Endometrial mRNA expression of steroid receptors did not explain the variability in timing of onset of luteolysis in heifers while the later onset of luteolysis in three-wave cycles was associated with later up-regulation of oxytocin receptor mRNA.

Summary Sentence

Increased endometrial oxytocin receptor mRNA was later for estrous cycles with three vs two follicle waves and synchronous with luteolysis, but mRNA for P4, ESR1, and ESR2 receptors decreased much earlier than luteolysis and similar in 2 and 3 wave cycles.

The ovarian hormones estrogen and progesterone orchestrate the transcriptional programs required to direct functions of the uterus for initiation and maintenance of pregnancy. Estrogen, acting via estrogen receptor alpha, regulates gene expression by activating and repressing distinct genes involved in signaling pathways that regulate cellular and physiological responses including cell division, water influx, and immune cell recruitment. Historically, these transcriptional responses have been postulated to reflect a biphasic physiological response. In this study, we explored the transcriptional responses of the ovariectomized mouse uterus to 17β-estradiol (E2) by RNA-seq to obtain global expression profiles of protein-coding transcripts (mRNAs) and long noncoding RNAs (lncRNAs) following 0.5, 1, 2, and 6 hours of treatment. The E2-regulated mRNA and lncRNA expression profiles in the mouse uterus indicate an association between lncRNAs and mRNAs that regulate E2-driven pathways and reproductive phenotypes in the mouse. The transient E2-regulated transcriptome is reflected in the time-dependent shifting of biological processes regulated in the uterus in response to E2. Moreover, high expression of some conserved lncRNAs that are E2 regulated in the mouse uterus are predictive of low overall survival in endometrial carcinoma patients (e.g., H19, KCNQ1OT1, MIR17HG, and FTX). Collectively, this study (1) describes a genomic approach for identifying E2-regulated lncRNAs that may serve critical function in the uterus and (2) provides new insights into our understanding of the regulation of hormone-regulated transcriptional responses with implications in pregnancy and endometrial pathologies.

Summary sentence

Estrogen regulates protein-coding genes and long noncoding RNAs with expression kinetics that reflect the shifting biological programs and functions of the uterus.

Astaxanthin (AST), a natural antioxidant carotenoid, has been shown to exert anti-inflammatory effects. However, to our knowledge, no study has specifically addressed the potential protective effects of AST against bovine endometritis. The purpose of this study was to examine whether treatment with AST could protect endometrial epithelial cells against lipopolysaccharide (LPS)-induced inflammatory injury. Treatment of bovine endometrial (BEND) epithelial cell line with AST reduced LPS-induced production of interleukin-6 and tumor necrosis factor-alpha, increased the cellular activity of superoxide dismutase and catalase, decreased the proportion of apoptotic cells, and promoted the production of insulin-like growth factor and epithelial growth factor. The effects of AST were mediated through the downregulation of B-cell lymphoma 2 (Bcl-2) associated X, apoptosis regulator (Bax), and cleaved caspase-3 and through the upregulation of Bcl-2. Moreover, AST significantly increased the expression of the tight junction proteins (TJP) claudin, cadherin-1, and TJP1, which play an essential role in the maintenance of host endometrial defense barrier against pathogen infection. Collectively, these results demonstrated that treatment with AST protected against oxidative stress, prevented cell apoptosis, promoted BEND cells viability, and increased the production of growth factors, in addition to activating the endometrial defense barrier. Therefore, AST is a promising therapeutic agent for the prevention and treatment of endometritis. This finding is of utmost importance in the present times when the excessive use of antibiotics has resulted in the development of antibiotic-resistant bacteria.

Summary sentence

Astaxanthin counteracts LPS-induced inflammation, oxidative stress, apoptosis, and tight junction disassembly in bovine endometrial epithelial cells, and is a potential therapeutic agent against bovine endometritis.

High density lipoproteins (HDL) take up cholesterol from peripheral tissues via ABC transporters and deliver it to the liver via scavenger receptor class B type I (SR-B1). HDL are the main lipoproteins present in follicular fluid (FF). They are thought to derive from plasma, but their origin is still controversial. SR-B1 knock-out (KO) mice have provided important evidence linking HDL metabolism and female fertility. These mice have cholesterol-rich circulating HDL and female infertility that can be restored by treating mice with the cholesterol-lowering drug probucol. Ovulated oocytes from SR-B1 KO females are dysfunctional and show excess cholesterol. The mechanisms explaining the contribution of FF HDL to oocyte cholesterol homeostasis are unknown. Here, using quantitation of filipin fluorescence we show that in SR-B1 KO ovaries, cholesterol excess is first observed in immature oocytes in antral follicles. By performing cross-transplant experiments between WT and apolipoprotein A-I deficient (ApoA-I KO) mice, which lack the main protein component of HDL, we provide evidence supporting the plasmatic origin of FF HDL. Also, we demonstrate that probucol treatment in SR-B1 KO females results in lowering of cholesterol content in their oocytes. Incubation of oocytes from SR-B1 KO mice with purified WT HDL reduces their cholesterol content, suggesting that HDL promote efflux of excess cholesterol from oocytes. In agreement with this hypothesis, we identified ABC transporters in oocytes and observed that ABCA1 KO oocytes have excess cholesterol and lower viability than WT oocytes.

Summary Sentence

Follicular fluid HDL and oocyte ABC transporters regulate mouse oocyte cholesterol homeostasis and contribute to female fertility.

Extracellular vesicles (EVs) are nanoparticles secreted by ovarian follicle cells. Extracellular vesicles are an important form of intercellular communication, since they carry bioactive contents, such as microRNAs (miRNAs), mRNAs, and proteins. MicroRNAs are small noncoding RNA capable of modulating mRNA translation. Thus, EVs can play a role in follicle and oocyte development. However, it is not clear if EV contents vary with the estrous cycle stage. The aim of this study was to investigate the bovine miRNA content in EVs obtained from follicles at different estrous cycle stages, which are associated with different progesterone (P4) levels in the follicular fluid (FF). We collected FF from 3 to 6 mm follicles and evaluated the miRNA profile of the EVs and their effects on cumulus-oocyte complexes during in vitro maturation. We observed that EVs from low P4 group have a higher abundance of miRNAs predicted to modulate pathways, such as MAPK, RNA transport, Hippo, Cell cycle, FoxO, oocyte meiosis, and TGF-beta. Additionally, EVs were taken up by cumulus cells and, thus, affected the RNA global profile 9 h after EV supplementation. Cumulus cells supplemented with EVs from low P4 presented upregulated genes that could modulate biological processes, such as oocyte development, immune responses, and Notch signaling compared with genes of cumulus cells in the EV free media or with EVs from high P4 follicles. In conclusion, our results demonstrate that EV miRNA contents are distinct in follicles exposed to different estrous cycle stage. Supplementation with EVs impacts gene expression and biological processes in cumulus cells.

Summary Sentence

MicroRNA contents of small EVs obtained from bovine follicular fluid are modified depending on the estrous cycle stage and can modulate the RNA profile of cumulus cells during in vitro oocyte maturation.

Despite its prevalence and the severity of symptoms, little is known about the pathogenesis and etiology of adenomyosis. In previous studies, the protein expression level of the polarity protein Scribble in the eutopic endometrium of patients with adenomyosis was found to be significantly decreased; however, little is known about its regulatory mechanism. In consideration of the important role of supraphysiologic estrogen production in the endometrium in the development of adenomyosis, we analyzed the effect and mechanism of estrogen on the expression of Scribble in vivo and in vitro. Firstly, we found Scribble was downregulated in eutopic endometrium and negatively related with aromatase P450 in tamoxifen-induced adenomyosis. Then, we established a 3D culture of primary endometrial epithelial cells and found that estrogen could disrupt apical-basal polarity of endometrial glandular epithelial cells. Based on the following experiments and GEO dataset screening, we found that estrogen regulates the expression level of Scribble by HECW1 through ubiquitination of Scribble protein. At last, we verified the expression of Scribble, HECW1, and aromatase P450 in eutopic endometrium of human and mouse specimens and found that the expression of HECW1 and aromatase P450 was significantly increased, while the expression of Scribble was significantly downregulated. Furthermore, a positive correlation was found between HECW1 and aromatase P450, while a negative correlation was found between HECW1 and Scribble in human clinical tissue specimens. Therefore, our research may provide a new understanding of the pathogenesis of adenomyosis.

Summary Sentence

In summary, estrogen induced disruption of apical-basal polarity in basal endometrial glandular epithelial cells through E3 ubiquitin ligase HECW1-mediated Scribble degradation might be one of the key mechanisms in the development of diffuse adenomyosis.

Metabolic demands of modern hybrid sows have increased over the years, which increases the chance that sows enter a substantial negative energy balance (NEB) during lactation. This NEB can influence the development of follicles and oocytes that will give rise to the next litter. To study effects of a lactational NEB on follicular development, we used 36 primiparous sows of which 18 were subjected to feed restriction (3.25 kg/day) and 18 were full-fed (6.5 kg/day) during the last 2 weeks of a 24.1 ± 0.3 day lactation. Feed restriction resulted in a 70% larger lactational body weight loss and 76% higher longissimus dorsi depth loss, but similar amounts of backfat loss compared to the full fed sows. These changes were accompanied by lower plasma insulin-like growth factor 1 (IGF1) and higher plasma creatinine levels in the restricted sows from the last week of lactation onward. Ovaries were collected 48 h after weaning. Restricted sows had a lower average size of the 15 largest follicles (–26%) and cumulus–oocyte complexes showed less expansion after 22 h in vitro maturation (–26%). Less zygotes of restricted sows reached the metaphase stage 24 h after in vitro fertilization and showed a higher incidence of polyspermy (+89%). This shows that feed restriction had severe consequences on oocyte developmental competence. Follicular fluid of restricted sows had lower IGF1 (–56%) and steroid levels (e.g., β-estradiol, progestins, and androgens), which indicated that follicles of restricted sows were less competent to produce steroids and growth factors needed for oocytes to obtain full developmental competence.

Summary Sentence

Premating feed restriction results in lower oocyte developmental competence, which might be explained by reduced follicular steroid and growth factor production.

The number of stockpiled primordial follicles is thought to be responsible for the fate of female fertility and reproductive lifetime. We previously reported that starvation in nonsuckling early neonatal mice increases the number of primordial follicles with concomitant autophagy activation, suggesting that autophagy may accelerate the formation of primordial follicles. In this study, we attempted to upregulate the numbers of primordial follicles by administering an autophagy inducer and evaluated the progress of primordial follicle formation and their fertility during the life of the mice. To induce autophagy, mice were intraperitoneally injected with the Tat-beclin1 D-11 peptide (0.02 mg/g body weight) at 6–54 h or 60–84 h after birth. In animals that received Tat-beclin 1 D-11 by 54 h after birth, the primordial follicle numbers were significantly increased compared with the control group at 60 h. The ratio of expressed LC3-II/LC3-I proteins was also significantly greater. The numbers of littermates from pregnant females that had been treated with Tat-beclin 1 D-11 were maintained at remarkably greater levels until 10 months old. These results were supported by an abundance of primordial follicles at even 13–15 months old.

Summary Sentence

An enhancement of autophagy in neonatal mice during the follicle formation period accelerates follicle assembly by promoting oocyte survival, leading to the expansion of primordial follicle pool and an improvement in individual lifelong fertility.

Circulating prostaglandin F2α metabolite (PGFM) after an oxytocin challenge was evaluated throughout the first 2 months of pregnancy in lactating Holstein cows. On day 11, 18, and 25 after artificial insemination (AI), and on days 32, 39, 46, 53, and 60 of pregnancy, cows were challenged with 50 IU oxytocin, i.m. Blood was collected before (0 min), 30, 60, 90, and 120 min after oxytocin for plasma PGFM concentrations. Ultrasound evaluations were performed for pregnancy diagnosis on day 32–60 post-AI. Nonpregnant (NP) cows on day 18 were designated by a lack of interferon-stimulated genes in peripheral blood leukocytes and Pregnant (P) based on day 32 ultrasound. On day 11, P and NP were similar with low PGFM and no effect of oxytocin on PGFM. On day 18, oxytocin increased PGFM (3-fold) in NP with little change in P cows. Comparing only P cows from day 11 to 60, basal circulating PGFM increased as pregnancy progressed, with day 11 and 18, lower than all days from day 25 to 60 of pregnancy. Oxytocin-induced PGFM in P cows on day 25 was greater than P cows on day 18 (2.9-fold). However, oxytocin-induced PGFM was lower on day 25 compared to day 53 and 60, with intermediate values on day 32, 39, and 46 of pregnancy. Thus, the corpus luteum (CL) of early pregnancy (day 11, 18) is maintained by suppression of PGF, as reflected by suppressed PGFM in this study. However, during the second month of pregnancy, uterine PGF secretion was not suppressed since basal PGFM and oxytocin-induced PGFM secretion were elevated. Apparently, mechanisms other than suppression of oxytocin receptors maintain CL after day 25 of pregnancy.

Summary Sentence

On day 18 of pregnancy, there is suppressed PGF production in response to oxytocin; however, at day 25–60 of pregnancy, there is increased basal PGF and increased oxytocin-induced PGF indicating the presence of oxytocin receptors and different mechanisms maintaining CL of pregnancy after day 25.

The underlying mechanism of the chemokine-C receptor 7 (CCR7) that leads to aberrant trophoblast migration and invasion in recurrent spontaneous abortion (RSA) remains unknown. CCR7 is considered crucial for migration and invasion and has been associated with the risk of miscarriage. However, the functional role of CCR7 in RSA is not fully understood. Our study found that CCR7 mRNA and protein abundance were significantly decreased in the villous from RSA patients compared with healthy controls. Knockdown of CCR7 caused a significant reduction of migration and invasion in JAR and JEG-3 cells. Meanwhile, CCR7 functioned as a positive upstream factor of the AKT pathway contributing to the expression of GATA2, promoting trophoblast migration, and invasion via MMP2. Notably, a decreased abundance of CCR7 was positively correlated with the phosphorylation of AKT and with an abundance of GATA2 and MMP2 in human villous specimens of RSA compared with the control group. CCL19, a ligand of CCR7, could promote trophoblast migration and invasion by activating the deregulation of the CCR7-mediated pathway in RSA. We are convinced that CCR7 and its downstream factors may be possible mechanisms for the pathogenesis of RSA.

Summary Sentence

Down-regulation of CCR7 is involved in the development of RSA.

Ferumoxytol is a superparamagnetic iron oxide nanoparticle used off-label as an intravascular magnetic resonance imaging (MRI) contrast agent. Additionally, ferumoxytol-uptake by macrophages facilitates detection of inflammatory sites by MRI through ferumoxytol-induced image contrast changes. Therefore, ferumoxytol-enhanced MRI holds great potential for assessing vascular function and inflammatory response, critical to determine placental health in pregnancy. This study sought to assess the fetoplacental unit and selected maternal tissues, pregnancy outcomes, and fetal well-being after ferumoxytol administration. In initial developmental studies, seven pregnant rhesus macaques were imaged with or without ferumoxytol administration. Pregnancies went to term with vaginal delivery and infants showed normal growth rates compared to control animals born the same year that did not undergo MRI. To determine the impact of ferumoxytol on the maternal–fetal interface (MFI), fetal well-being, and pregnancy outcome, four pregnant rhesus macaques at ∼100 gestational day underwent MRI before and after ferumoxytol administration. Collection of the fetoplacental unit and selected maternal tissues was performed 2–3 days following ferumoxytol administration. A control group that did not receive ferumoxytol or MRI was used for comparison. Iron levels in fetal and MFI tissues did not differ between groups, and there was no significant difference in tissue histopathology with or without exposure to ferumoxytol, and no effect on placental hormone secretion. Together, these results suggest that the use of ferumoxytol and MRI in pregnant rhesus macaques does not negatively impact the MFI and can be a valuable experimental tool in research with this important animal model.

Summary Sentence

Ferumoxytol magnetic resonance imaging for non-invasive pregnancy monitoring of the rhesus macaque does not impact histopathology or iron content of the maternal–fetal interface.

In our earlier work, we found that intrauterine (i.u.) and intraperitoneal (i.p.) injection of LPS (10-µg serotype 0111:B4) induced preterm labor (PTL) with high pup mortality, marked systemic inflammatory response and hypotension. Here, we used both i.u. and i.p. LPS models in pregnant wild-type (wt) and CCR2 knockout (CCR2–/–) mice on E16 to investigate the role played by the CCL2/CCR2 system in the response to LPS.

Basally, lower numbers of monocytes and macrophages and higher numbers of neutrophils were found in the myometrium, placenta, and blood of CCR2–/– vs. wt mice. After i.u. LPS, parturition occurred at 14 h in both groups of mice. At 7 h post-injection, 70% of wt pups were dead vs. 10% of CCR2–/– pups, but at delivery 100% of wt and 90% of CCR2–/– pups were dead. Myometrial and placental monocytes and macrophages were generally lower in CCR2–/– mice, but this was less consistent in the circulation, lung, and liver. At 7 h post-LPS, myometrial ERK activation was greater and JNK and p65 lower and the mRNA levels of chemokines were higher and of inflammatory cytokines lower in CCR2–/– vs. wt mice. Pup brain and placental inflammation were similar. Using the IP LPS model, we found that all measures of arterial pressure increased in CCR2–/– but declined in wt mice.

These data suggest that the CCL2/CCR2 system plays a critical role in the cardiovascular response to LPS and contributes to pup death but does not influence the onset of inflammation-induced PTL.

Summary Sentence

This study used mouse models of preterm labour and sepsis to show that during pregnancy the CCL2/CCR2 system is important in the cardiovascular response to sepsis but while it delays pup death it does not delay LPS-induced preterm labour.

Survival and growth of the bovine conceptus (embryo and associated extraembryonic membranes) are dependent on endometrial secretions or histotroph found in the uterine lumen. Previously, serial embryo transfer was used to classify heifers as high fertile (HF), subfertile (SF), or infertile (IF). Here, we investigated specific histotroph components [glucose, prostaglandins (PGs), and lipids] in the uterine lumen of day 17 pregnant and open fertility-classified heifers. Concentrations of glucose in the uterine lumen were increased by pregnancy but did not differ among fertility-classified heifers. Differences in expression of genes encoding glucose transporters and involved with glycolysis and gluconeogenesis were observed between conceptuses collected from HF and SF heifers. In the uterine lumen, PGE2 and PGF2α were increased by pregnancy, and HF heifers had higher concentrations of PGE2, PGF2α, and 6-keto-PFG1α than SF heifers. Differences were found in expression of genes regulating PG signaling, arachidonic acid metabolism, and peroxisome proliferator-activated receptor signaling among conceptuses and endometrium from fertility-classified heifers. Lipidomics was conducted exclusively in samples from HF heifers, and phosphatidylcholine was the main lipid class that increased in the uterine lumen by pregnancy. Expression of several lipid metabolism genes differed between HF and SF conceptuses, and a number of fatty acids were differentially abundant in the uterine lumen of pregnant HF and SF heifers. These results support the ideas that uterine luminal histotroph impacts conceptus survival and programs its development and is a facet of dysregulated conceptus–endometrial interactions that result in loss of the conceptus in SF cattle during the implantation period of pregnancy establishment.

Summary Sentence

Conceptus–endometrium interactions differ in fertility-classified heifers and impact uterine luminal contents.

Pig conceptuses secrete estrogens (E2), interleukin 1 beta 2 (IL1B2), and prostaglandins (PGs) during the period of rapid trophoblast elongation and establishment of pregnancy. Previous studies established that IL1B2 is essential for rapid conceptus elongation, whereas E2 is not essential for conceptus elongation or early maintenance of the corpora lutea. The objective of the present study was to determine if conceptus expression of prostaglandin-endoperoxide synthase 2 (PTGS2) and release of PG are important for early development and establishment of pregnancy. To understand the role of PTGS2 in conceptus elongation and pregnancy establishment, a loss-of-function study was conducted by editing PTGS2 using CRISPR/Cas9 technology. Wild-type (PTGS2^+/+) and null (PTGS2^–/–) fibroblast cells were used to create embryos through somatic cell nuclear transfer. Immunolocalization of PTGS2 and PG production was absent in cultured PTGS2^–/– blastocysts on day 7. PTGS2^+/+ and PTGS2^–/– blastocysts were transferred into surrogate gilts, and the reproductive tracts were collected on either days 14, 17, or 35 of pregnancy. After flushing the uterus on days 14 and 17, filamentous conceptuses were cultured for 3 h to determine PG production. Conceptus release of total PG, prostaglandin F2α (PGF2α), and PGE in culture media was lower with PTGS2^–/– conceptuses compared to PTGS2^+/+ conceptuses. However, the total PG, PGF2α, and PGE content in the uterine flushings was not different. PTGS2^–/– conceptus surrogates allowed to continue pregnancy were maintained beyond 30 days of gestation. These results indicate that pig conceptus PTGS2 is not essential for early development and establishment of pregnancy in the pig.

Summary Sentence

Ablation of pig conceptus PTGS2 expression decreases prostaglandin production but does not affect pregnancy establishment and maintenance to 35 days of gestation.

The Leydig cells of the mammalian testis produce testosterone (T) in response to luteinizing hormone (LH). In rats and men with reduced serum T levels, T replacement therapy (TRT) will raise T levels, but typically with suppressive effects on sperm formation. The rate-determining step in T formation is the translocation of cholesterol to the inner mitochondrial membrane, mediated by protein–protein interactions of cytosolic and outer mitochondrial membrane proteins. Among the involved proteins is cholesterol-binding translocator protein (TSPO) (18 kDa TSPO). We hypothesized that in contrast to TRT, the administration of the TSPO agonist N,N-dihexyl-2-(4-fluorophenyl)indole-3-acetamide (FGIN-1-27), by stimulating the ability of the Leydig cells to produce T, would result in the elevation of serum T levels while maintaining intratesticular T concentration and therefore without suppression of spermatogenesis. Age-related reductions in both serum and intratesticular T levels were seen in old Brown Norway rats. Both exogenous T and FGIN-1-27 increased serum T levels. With exogenous T, serum LH and Leydig cell T formation were suppressed, and intratesticular T was reduced to below the concentration required to maintain spermatogenesis quantitatively. In contrast, FGIN-1-27 stimulated Leydig cell T formation, resulting in increased serum T without reductions in intratesticular T concentrations or in testicular sperm numbers. FGIN-1-27 also significantly increased serum and intratesticular T levels in rats made LH-deficient by treatment with the gonadotropin-releasing hormone antagonist cetrorelix. These results point to a possible approach to increasing serum T without negative effects on spermatogenesis, based upon stimulating T production by the Leydig cells themselves rather than administering T exogenously.

Summary Sentence

The TSPO agonist FGIN-1-27 stimulates the ability of the Leydig cells producing testosterone and results in elevating serum and intratesticular testosterone without negative effect on spermatogenesis.

The full-term development of the xenogeneic embryo in the uterus of the mother of different species is very restricted and can occur only in certain groups of closely related mammals. In the case of mouse ↔ rat chimeras, the interspecific uterine barrier is less hostile to interspecific chimeric fetuses. In current work, we tested the development of mouse and rat fetuses in uteri of females of the opposite species. We created chimeric mouse ↔ rat blastocysts by injection of mouse embryonic stem cells (ESCs) into eight-cell rat embryos and rat ESCs into eight-cell mouse embryos. Chimeras were transferred to the foster mothers of the opposite species. Despite a huge number of transferred embryos (>1000 in total for both variants), only one live fetus derived solely from the mouse ESCs was isolated at E13.5 from the rat uterus. All other fetuses and newborns were chimeric or were built only from the cells of the recipient embryo. We examined the possible reason for such an outcome and found that the xenogeneic fetuses are eliminated at the perigastrulation stage of development. Thus, we conclude that in the rat ↔ mouse combination even when extraembryonic tissues of the chimeric embryo are composed solely of the cells of the same species as the female to which embryos are transferred, the full-term development of the pure xenogeneic fetus is very unlikely.

Summary sentence

Full-term development of pure xenogeneic fetuses in the rat ↔ mouse model is very unlikely.

Pentachloronitrobenzene (PCNB) is an organochlorine fungicide widely used for crop production and has become an environmental concern. Little is known about the effect of PCNB on ovarian steroidogenesis and follicular development. We found that PCNB stimulated Star expression and progesterone production in cultured rat granulosa cells in a dose-dependent manner. PCNB activated mitogen-activated protein kinase (MAPK3/1) extracellulat regulated kinase (ERK1/2), thus inhibition of either protein kinase A (PKA) or MAPK3/1 signaling pathway significantly attenuated progesterone biosynthesis caused by PCNB, suggesting that PCNB induced progesterone production by activating the cyclic adenosine monophosphate (cAMP/PKA) and MAPK3/1 signaling pathways. Further investigation demonstrated that PCNB induced Star expression and altered MAPK3/1 signaling in ovary tissues of immature SD rats treated with PCNB at the dose of 100, 200, or 300 mg/kg by daily gavage for 7 days, while serum progesterone level was dose-dependently decreased. We demonstrated that PCNB exposure accelerated the recruitment of primordial follicles into the growing follicle pool in ovary tissues, accompanied by increased levels of anti-Mullerian hormone (AMH) in both ovary tissues and serum. Taken together, our data demonstrate for the first time that PCNB stimulated Star expression, altered MAPK3/1 signaling and progesterone production in vivo and in vitro, and accelerated follicular development with a concomitant increase in AMH in ovary tissues and serum. Our findings provide novel insight into the toxicity of PCNB to animal ovary function.

Summary Sentence

Pentachloronitrobenzene stimulated Star expression, altered progesterone content, and accelerated primordial follicle recruitment with a concomitant increase of anti-Mullerian hormone in ovary tissues and serum.