Proinflammatory cytokine gene expression in endometrial cytobrush samples harvested from cows with and without subclinical endometritis

Biosynthetic pathway for leukotrienes is stimulated by lipopolysaccharide and cytokines in pig endometrial stromal cells

An inflammatory response is related to different inflammatory mediators generated by immune and endometrial cells. The links between lipopolysaccharide (LPS), cytokines, and leukotrienes (LTs) in endometrial stromal cells remain unclear. This study aimed to examine the influence of LPS, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-4 and IL-10 on 5-lipooxygenase (5-LO), LTA4 hydrolase (LTAH) and LTC4 synthase (LTCS) mRNA and protein abundances, and LTB4 and cysteinyl (cys)-LTs release including LTC4, by the cultured pig endometrial stromal cells, as well as on cell viability. 24-hour exposure to LPS, TNF-α, IL-4 and IL-10 up-regulated 5-LO mRNA and protein abundances. LPS increased LTAH mRNA abundance, while TNF-α, IL-1β and IL-10 augmented LTAH mRNA and protein abundances. TNF-α and IL-4 increased LTCS mRNA and protein abundances. In addition, LTCS mRNA abundance was enhanced by LPS and IL-4, while LTCS protein abundance was increased by IL-1β. Cells responded to LPS, TNF-α, IL-1β and IL-10 with increased LTB4 release. TNF-α, IL-1β and IL-4 stimulated LTC4 release. Cys-LTs release was up-regulated by LPS, TNF-α, IL-1β and IL-4. All studied cytokines augmented cell viability. In summary, LPS, TNF-α, IL-1β, IL-4 and IL-10 are potential LTs immunomodulatory agents in endometrial stromal cells. These functional interactions could be one of the mechanisms responsible for local orchestrating events in inflamed and healthy endometrium.

Profile of cytokine gene expression of the endometrium and its relationship to inflammation and fertility in postpartum dairy cows

To clarify the profile of endometrial cytokines and their relation to inflammation and fertility, mRNA expressions of interleukin (IL)-1α, -1β, -8, -10 and tumor necrosis factor (TNF)-α at weeks (W) 3, 5, and 7 postpartum were compared between Holstein cows without and with cytological endometritis and between early (≤90 days) and delayed (>90 days postpartum) conception cows. IL-1α, IL-1β, and IL-8 expressions at W5 and W7 were significantly higher in cows with cytological endometritis than without. While IL-1α, IL-1β, IL-8, and TNF-α expressions decreased from W3 to W5 in all early conception cows, the percentage of cows decreasing these mRNA was significantly lower in delayed conception cows than early conception cows. Evaluating endometrial cytokine expression in dairy cows helps diagnose cytological endometritis and estimate fertility.

Influence of sub-clinical endometritis on early pregnancy predictors and proinflammatory cytokines in circulating immune cells in dairy cows

In Experiment 1, PBMC were isolated from cows considered healthy or with SCE (n=6/group) on Days 0 (estrus) and 7 (diestrus) of a synchronized estrous cycle. In Experiment 2, on D21 (D0 was defined as the day of Fixed Timed Artificial Insemination (FTAI), cows were evaluated by ultrasonography to assess luteal blood perfusion and PBMC were isolated. On D32, cows were classified into: healthy pregnant (n=7), pregnant with SCE (n=4), healthy non-pregnant (n=8), and non-pregnant with SCE (n=10). Gene expression of ISGs (ISG15, OAS1, MX1 and IFI6) and proinflammatory cytokines (IL1-β, TNF-α and IFN-γ) were determined. Expression of ISG15, MX1, IFI6, TNF-α and IFN-γ did not differ between SCE and healthy cows and between Days 0 and 7. Expression of OAS1 and IL1-β were higher (P=0.02) on Day 7 than Day 0, regardlees of the SCE presence. In Exp.2, ISG15 abundance was 2.5-fold greater (P=0.0008), TNF-α was 2.2-fold greater (P=0.05), and IL1-β tended (P=0.06) to be 2.4-fold higher in pregnant than non-pregnant cows. Luteal blood perfusion was greater (P=0.01) in pregnant animals. In conclusion, OAS1 and IL1-β are transcripts upregulated in PBMC at diestrus, regardless of SCE occurrence. Proinflammatory cytokines are not affected by SCE occurrence, but IL1-β and TNF-α are upregulated in pregnant animals on D21 of pregnancy. ISG15 abundance is a good pregnancy predictor, regardless SCE presence.

Ovarian sex steroid and epithelial control of immune responses in the uterus and oviduct: human and animal models†

The female reproductive tract (FRT), including the uterus and oviduct (Fallopian tube), is responsible for maintaining an optimal microenvironment for reproductive processes, such as gamete activation and transportation, sperm capacitation, fertilization, and early embryonic and fetal development. The mucosal surface of the FRT may be exposed to pathogens and sexually transmitted microorganisms due to the opening of the cervix during mating. Pathogens and endotoxins may also reach the oviduct through the peritoneal fluid. To maintain an optimum reproductive environment while recognizing and killing pathogenic bacterial and viral agents, the oviduct and uterus should be equipped with an efficient and rigorously controlled immune system. Ovarian sex steroids can affect epithelial cells and underlying stromal cells, which have been shown to mediate innate and adaptive immune responses. This, in turn, protects against potential infections while maintaining an optimal milieu for reproductive events, highlighting the homeostatic involvement of ovarian sex steroids and reproductive epithelial cells. This article will discuss how ovarian sex steroids affect the immune reactions elicited by the epithelial cells of the non-pregnant uterus and oviduct in the bovine, murine, and human species. Finally, we propose that there are regional and species-specific differences in the immune responses in FRT.

Local and systemic inflammatory response to the intrauterine infusion of enzymes during estrus in water buffaloes with subclinical endometritis

Our objective was to determine the effects of intrauterine infusion of proteolytic enzymes in buffaloes with subclinical endometritis (SCE) at estrus on the resolution of endometrial inflammation and reproductive performance. Buffaloes at spontaneous estrus (E1) were screened for SCE by endometrial cytology to identify SCE (≥5% PMN, n = 22) and non-SCE (<5% PMNs, n = 14) animals. All buffaloes underwent uterine ultrasonographic examination, low volume uterine lavage (cytokines and acute phase proteins) and blood sampling (cytokines and acute-phase proteins) at E1. On the same day (E1), SCE buffaloes were randomly selected either for intrauterine infusion of proteolytic enzymes (ENY, n = 11) or saline (PC, n = 11). Buffaloes without SCE were kept as untreated control (NC; n = 14). All buffaloes were re-examined and re-sampled during subsequent estrus (E2), inseminated during the following estrus (E3), and assessed for fertility related outcomes. Proteolytic infusion resulted a reduction in uterine PMN (P < 0.01) in SCE buffaloes. The concentrations of interleukin (IL)-1β and tumor necrosis factor (TNF)-α in uterus, and TNF-α and IL-10 in serum were higher (P < 0.01) at E1 in buffaloes with SCE (PC and ENY) compared to NC. After treatment, uterine IL-1β and TNF-α (P = 0.02), and serum TNF-α and IL-10 were lower within the animals of ENY group (P < 0.01). Before treatment, buffaloes with SCE had higher concentrations (P < 0.01) of serum and uterine amyloid-A and haptoglobin, which decreased (P < 0.01) after treatment in the ENY group. None of the fertility outcomes differ between the treatment groups. In conclusion, intrauterine infusion of proteolytic enzymes reduced endometrial inflammation; however, did not improve reproductive outcomes.

Effect of subclinical endometritis and flunixin meglumine administration on pregnancy in embryo recipient beef cows

Fertility of recipient beef cows with subclinical endometritis (SCE) that did or did not receive flunixin meglumine (FM) treatment were compared following transfer of d 7 embryo. The study population comprised of 600 Angus cross cows that expressed estrus following Select-Synch + CIDR (Controlled Internal Drug Release) estrus synchronization protocol. At the time of embryo transfer, approximately 3 wk after sampling for subclinical endometritis, cows were randomly allocated either to receive FM treatment (500 mg of Banamine®; n = 300) or not (Control; n = 300). The effect of subclinical endometritis (at ≥ 1% PMN on endometrial cytology by cytobrush method) and FM treatment on pregnancy/embryo transfer (P/ET, %) were evaluated by mixed model. Of the 600 cows, 323 (53.8%) became pregnant; 55.0% (165/300) cows that received FM treatment vs. 52.7% (158/300) control cows (P > 0.1), and 55.9% (266/476) normal vs. 46.0% (57/124) subclinical endometritis cows (P < 0.05). There was a trend for treatment by subclinical endometritis for P/ET (P = 0.09). Pregnancy was recorded in 55.3% (134/242) of normal and 53.4% (31/58) of subclinical endometritis cows that received FM treatment, and in 56.4% (132/234) of normal and 39.4% (26/66) of subclinical endometritis cows that did not receive FM treatment (P = 0.09). In conclusion, subclinical endometritis in recipient beef cows resulted in lower P/ET. Though not significant in cows with subclinical endometritis, FM treatment resulted in 14.0% points more pregnancy compared with control.

Interaction of sperm cells with the female reproductive tract in cattle: Focus on neutrophil extracellular trap formation

After insemination of cows, either naturally or artificially, the deposition of semen into the vagina or uterus results in an immune reaction which is based on polymorphonuclear neutrophil activity. Sperm must be resistant to immune system actions of the female for an adequate time to allow fertilization to occur. Neutrophils, however, either directly phagocytize sperm through cell-cell attachment or entrap sperm cells in neutrophil extracellular traps (NETs), structures consisting of neutrophil nuclear DNA and associated proteins. In this review article, the interaction of neutrophils and sperm cells in t cattle will be described, with a special focus on the formation of neutrophil extracellular traps (NETs).

In Vitro Effects of Short-Term and Long-Term Heat Exposures on the Immune Response and Prostaglandin Biosynthesis in Bovine Endometrial Cells

Worldwide heat stress (HS) conditions have a negative impact on dairy cow fertility. However, understanding of the effect of heat stress on endometrial functions is still unclear. The present study aimed to investigate the effects of differential heat exposure conditions on the immune response and prostaglandin biosynthesis of bovine endometrium challenged with bacterial lipopolysaccharide (LPS). Cultures of endometrial cells were grown to confluence at 37 °C (control) and 40.4 °C for 24 h after confluence (short-term heat exposure) and 40.4 °C for 8 days from the beginning of the culture (long-term heat exposure), prior to a challenge by 100 ng/mL LPS for 12 h. LPS altered ALOX12, IL8, IL1B, S100A8, PTGES and AKR1B1 expressions, as well as secretory IL8 and PGF2α. Short-term heat exposure decreased S100A8, IL8 and PGF2α compared with the control temperature, while long-term heat exposure decreased S100A8 and PGF2α. In contrast, HSPA5 expression was not altered by heat exposure or LPS. Indeed, the short-term heat treatment was insufficient for accomplishing the responses of the endometrium to LPS treatment for IL8, S100A8 and PTGES expressions when compared with other temperature conditions. Our findings showed that heat exposure could compromise endometrium immune response and prostaglandin biosynthesis in different ways based on elevated temperature duration, which could reduce subsequent fertility.

Effects of Intrauterine Infusion of Micronised Purified Flavonoid Fraction (MPFF) in Metritis-Diagnosed Dairy Cows Naturally Infected by E. coli during the Early Postpartum

The occurrence of metritis during the postpartum period causes serious economic losses in dairy cattle. The Micronised Purified Flavonoid Fraction (MPFF) is a polyphenolic flavonoid compound which is considered to have many health-related properties such as antibiotic, anti-inflammatory, phlebotonic, and several vascular-protecting activities. The aim was to evaluate the effects of a new strategic therapy for metritis based on MPFF intrauterine infusions during the early postpartum in dairy cows naturally infected by Escherichia coli. The clinical effects on reproductive anatomical structures and chronological involution dynamics were monitored until day 24 postpartum by ultrasonography. Moreover, uterine bacteriological and cytological (polymorphonuclear neutrophils; PMNs) profiles were analysed before and after MPFF infusion. The results showed that the success rate (% cure) at day 24 postpartum was improved significantly when using higher MPFF doses (p < 0.05). Moreover, MPFF treatment acutely diminished the size of the cervix and uterus and improved the involution process during the first 24 days (p < 0.05). The prevalence of pathogenic bacteria found in in vitro cultures was significantly variable (p < 0.01), as were the antibiotic sensitivity patterns. Pathogenic bacteria isolates decreased after MPFF applications in a dose−response fashion (p < 0.01), while isolates obtained from controls and low-dose-MPFF-treated animals were stable and similar (p > 0.05). The sensitivity patterns of pathogenic bacteria isolated in in vitro cultures from MPFF-treated animals were variable, although resistance to E. coli, Staphylococcus aureus, Bacillus spp., and coliforms was shown irrespective of the MPFF doses used. However, MPFF-treated cows showed a dose−response effect regarding PMN rates (p < 0.05). The calving-first service, calving−conception interval, and conception rate improved significantly from using higher MPFF doses (p < 0.05). In conclusion, this study shows that MPFF treatment differentially affects uterine involution, bacteriological profiles, cytological traits, and reproductive performance in metritis-positive dairy cows naturally infected by E. coli.

Lactobacillus rhamnosus GR-1 Alleviates Escherichia coli-Induced Inflammation via NF-κB and MAPKs Signaling in Bovine Endometrial Epithelial Cells

Escherichia coli counts as a major endometritis-causing pathogen among dairy cows, which lowered the economic benefits of dairy farming seriously. Probiotic consumption has been reported to impart beneficial effects on immunomodulation. However, the inflammatory regulation mechanism of probiotics on endometritis in dairy cows remains unexplored. The current work aimed to clarify the mechanism whereby Lactobacillus rhamnosus GR-1 (L. rhamnosus GR-1) resists bovine endometrial epithelial cells (BEECs) inflammatory injury induced by E. coli. The model of cellular inflammatory injury was established in the BEECs, which comes from the uterus of healthy dairy cows using E. coli. The outcome of L. rhamnosus GR-1 addition on inflammation was evaluated in BEECs with E. coli-induced endometritis. The underlying mechanisms of anti-inflammation by L. rhamnosus GR-1 were further explored in E. coli-stimulated BEECs. In accordance with the obtained results, the use L. rhamnosus GR-1 alone could not cause the change of inflammatory factors, while L. rhamnosus GR-1 could significantly alleviate the expression of E. coli-induced inflammatory factors. Based on further study, L. rhamnosus GR-1 significantly hindered the TLR4 and MyD88 expression stimulated by E. coli. Moreover, we observed that in BEECs, L. rhamnosus GR-1 could inhibit the E. coli-elicited expressions of pathway proteins that are associated with NF-κB and MAPKs. Briefly, L. rhamnosus GR-1 can effectively protect against E. coli-induced inflammatory response that may be closely related to the inhibition of TLR4 and MyD88 stimulating NF-κB and MAPKs.

Isolation and characterization of eosinophils in bovine blood and small intestine

An effective method to isolate functional eosinophils from blood and tissues is required to analyze the multiple roles eosinophils play in innate immunity and tissue homeostasis. Highspeed cell sorting was used to isolate bovine eosinophils from blood polymorphonuclear (PMN) cells and from small intestine intraepithelial leukocytes. Eosinophils and neutrophils were purified from bovine blood with highspeed cell sorting after gating on autofluorescence (FL1) high and low PMN subpopulations. Highspeed sorting of intestinal eosinophils was accomplished by using a combination of positive (CD45⁺, CD11c^Low, side scatter^High) and negative (CD3^-) selection parameters. Eosinophils sorted from blood PMNs were 88.6 ± 5.8 % (mean + 1 SD; n = 4) pure and yielded significantly (p < 0.05) more RNA than purified neutrophils. Analysis of Toll-like receptor (TLR) gene expression and TLR ligand-induced pro-inflammatory cytokine (IL-1, IL-6, IL-8, and TNFα) gene expression demonstrated significant (p < 0.01) functional differences between blood eosinophils and neutrophils. Eosinophils varied between 14.7 % to 29.3 % of CD45⁺ IELs and purity of sorted intestinal eosinophils was 95 + 3.5 % (mean + 1SD; n = 5). A comparison of mucosal and blood eosinophils revealed significant (p < 0.01) differences in TLR gene expression, supporting the hypothesis that functionally distinct eosinophil populations are present in blood and tissues. In conclusion, highspeed cell sorting provides an effective method to isolate viable eosinophils from blood and tissues that can then be used for transcriptome analyses and in vitro function assays.

Methionine supply during the peripartum period and early lactation alter immunometabolic gene expression in cytological smear and endometrial tissue of holstein cows

The objective of the present study was to evaluate the effect of feeding rumen-protected methionine (RPM) during the peripartal period and early lactation on mRNA gene expression profiles of uterine cytological smear and endometrial samples of Holstein cows (n = 20). Treatments consisted of a supplementation with RPM [MET; n = 11; RPM at a rate of 0.08 % of DM: Lys:Met = 2.8:1, (Smartamine® M Adisseo, Alpharetta, GA, USA)] and no supplementation (CON; n = 9; Lys:Met = 3.5:1). Uterine cytology smears and endometrial samples were collected at 15, 30, and 73 days in milk (DIM) and analyzed for expression of genes related with metabolism, inflammation, and methionine metabolism. Regarding the cytological smear samples, RPM supplementation tended to increase mRNA expression of methionine adenosyltransferase 1 alpha (MAT1A) and increased the mRNA expression of fibroblast growth factor 7 (FGF7), with an effect of time for the latter. On the other hand, RPM decreased mRNA expression for glucose transporter 4 (GLUT4), interleukin 1 beta (IL-1β), interleukin 6 (IL-6), interleukin 8 (IL-8), prostaglandin E synthase 3 (PTGES3), translocator protein 18 kDa (TSPO), mucin 1 (MUC1) and superoxide dismutase (SOD1) in cytological smear samples. There was an effect of time for all variables except MAT1A, with decreasing expression over time. There was a TRT × TIME interaction for GLUT4 mRNA expression, with higher GLUT4 mRNA expression for cows fed CON than for cows fed RPM at time 15 and a tendency to higher expression for cows fed CON on time 30 when compared with cows fed RPM. For uterine tissue samples, feeding RPM increased the mRNA expression of lecithin-cholesterol acyltransferase (LCAT), S-adenosyl-l-homocysteine hydrolase (SAAH), FGF7, GLUT4, and apolipoproteins 3 (APOL3), with an effect of time for APOL3 where its expression increased over time. There was a tendency for cows fed RPM to have decreased IL1β mRNA expression. In conclusion, feeding RPM during transition period and early lactation is beneficial for uterine immune response and metabolism in early lactation as indicated by the favorable expressions of genes affecting the uterine immunometabolism during such a challenging period.

Neutrophil extracellular traps in cattle health and disease

Neutrophils largely contribute to the first line of defense against the invasion of pathogens. They kill pathogens basically by the following mechanisms: phagocytosis and proteolytic degradation, the release of enzymes with bactericidal activities, and the production of fibers to entrap pathogens, also known as neutrophil extracellular traps (NETs). NETs capture pathogens as a mechanism of immune protection and have been studied in-depth in various fields of human medicine. However, research about NETs in cattle is relatively scarce. The present article reviews the generation mechanisms, structural composition, signal pathways, advantages (and disadvantages) of NETs, and summarizes the latest findings of NETs in cattle health and disease.

Effect of Endometrial Sampling Procedures on Subsequent Pregnancy Rate of Cattle

Endometrial infections are a common cause of reproductive loss in cattle. Accurate diagnosis is important to reduce the economic losses caused by endometritis. A range of sampling procedures have been developed which enable collection of endometrial tissue or luminal cells or uterine fluid. However, as these are all invasive procedures, there is a risk that sampling around the time of breeding may adversely affect subsequent pregnancy rate. This systematic review compared the pregnancy rates (PR) of cattle which underwent uterine lavage (UL), cotton swab (CS), cytobrush (CB), cytotape (CT), or endometrial biopsy (EB) sampling procedures with those that were not sampled. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) protocol, relevant databases, including Pubmed, Web of Science, CAB Abstracts, VetMed Resource-Ruminants, and Scopus, were searched. The outcome measured was the pregnancy rate after the collection of endometrial sample(s). Seven studies, involving a total of 3693 cows, fulfilled the inclusion criteria for the systematic review and allowed the comparison of PR between sampled (n = 1254) and non-sampled cows (n = 2409). The results of the systematic review showed that endometrial sampling procedures can be performed before breeding or shortly after insemination without adversely affecting pregnancy rates in cattle. However, further studies are needed to validate this information.

A comparative analysis of the intrauterine transcriptome in fertile and subfertile mares using cytobrush sampling

Background

Subfertility is a major problem in modern horse breeding. Especially, mares without clinical signs of reproductive diseases, without known uterine pathogens and no evidence of inflammation but not becoming pregnant after several breeding attempts are challenging for veterinarians. To obtain new insights into the cause of these fertility problems and aiming at improving diagnosis of subfertile mares, a comparative analysis of the intrauterine transcriptome in subfertile and fertile mares was performed. Uterine cytobrush samples were collected during estrus from 57 mares without clinical signs of uterine diseases. RNA was extracted from the cytobrush samples and samples from 11 selected subfertile and 11 fertile mares were used for Illumina RNA-sequencing.

Results

The cytobrush sampling was a suitable technique to isolate enough RNA of high quality for transcriptome analysis. Comparing subfertile and fertile mares, 114 differentially expressed genes (FDR = 10%) were identified. Metascape enrichment analysis revealed that genes with lower mRNA levels in subfertile mares were related to ‘extracellular matrix (ECM)’, ‘ECM-receptor interaction’, ‘focal adhesion’, ‘immune response’ and ‘cytosolic calcium ion concentration’, while DEGs with higher levels in subfertile mares were enriched for ‘monocarboxyl acid transmembrane transport activity’ and ‘protein targeting’.

Conclusion

Our study revealed significant differences in the uterine transcriptome between fertile and subfertile mares and provides leads for potential uterine molecular biomarkers of subfertility in the mare.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07701-3.

Gut microbiota mediate the protective effects on endometritis induced by Staphylococcus aureus in mice

Endometritis, the inflammation of the endometrial lining caused by bacterial pathogens, is associated with reproductive failure. Recent studies have shown that gut microbiota play an important role in infectious diseases. However, the roles of the gut microbiota in endometritis remain unclear. Here, we assessed the effects and mechanisms of the gut microbiota during endometritis induced by Staphylococcus aureus (S. aureus). A mouse gut microbiota-dysbiosis model was established by a mixture of antibiotics (Abx) and subsequently, a model of endometritis was established by the uterine perfusion of S. aureus. Fecal microbiota transplantation (FMT) was performed to evaluate the relationship between gut microbiota and endometritis. The results showed that the mice with gut microbiota-dysbiosis developed uterine inflammation, while this inflammatory response of the uterus was alleviated in mice with FMT to gut microbiota-dysbiosis. In addition, S. aureus-induced endometritis was greater in severity in the mice with gut dysbiosis as compared to the untreated mice. Moreover, these effects were reversed in mice with FMT to the gut microbiota-dysbiosis. GC-MS analysis demonstrated that the levels of short-chain fatty acids (SCFAs) in the feces of mice with gut microbiota-dysbiosis significantly decreased and pretreatment with sodium butyrate or sodium propionate increased the concentrations of butyrate or propionate in both the circulation and uterine tissues, thereby reducing the severity of endometritis induced by S. aureus. In addition, the increased pathogen load in the uteri of the mice with gut microbiota-dysbiosis was associated with a reduction in the phagocytic ability and responsiveness of neutrophils. In conclusion, the gut microbiota offer a protective effect against S. aureus-induced endometritis by regulating the levels of SCFAs and maintaining the phagocytic ability and responsiveness of neutrophils.

Prediction of Calving to Conception Interval Length Using Algorithmic Analysis of Endometrial mRNA Expression in Bovine

Simple Summary

Our study aimed to develop the unsupervised clustering model based solely on selected markers to investigate the association between calving conception interval length, subclinical endometritis, and endometrial gene expression. An algorithmic analysis of endometrial gene expression showed a higher predictive ability to identify cows exhibiting excellent fertility than previously used methods, highlighting the correlation between INHBA/INHA and calving–conception interval length.

Abstract

After parturition, the uterus undergoes significant reconstruction, allows the endometrium to create an environment for subsequent embryo development. Here, we used an unsupervised algorithmic approach to select characteristic endometrial mRNA expression patterns of proposed markers and investigate each marker’s role as an individual indicator of reproductive success. Clinically healthy cows at a sixth week postpartum were examined, the percentage of neutrophils (PMNs%) in the cytological smear was calculated, and an endometrial biopsy was taken for qPCR. Based on pregnancy examination, cows were divided into three groups: Pregnant before 100 days postpartum (P100, n = 11), pregnant between 100–200-day (P200, n = 14), and culled (C, n = 10). Animals were also classified based on two PMNs% thresholds > 5% PMNs and > 10% PMNs. The expression of IL1B, IL6, CXCL8, and IL17A was higher in >10%PMNs. The expression of PTGS1 was higher in the P200 compared to P100. Upregulation of inhibin A subunit (INHA) and downregulation of inhibin β A subunit (INHBA) were observed in the P100. INHBA/INHA ratio was the most accurate linear predictor of the calving-to-conception interval. The application of the k-means algorithm allowed the identification of five unique expression patterns. The sensitivity and specificity of predicting allocation to P100 were 81% and 79%. We also documented the low efficiency of genes associated with subclinical endometritis and PMNs% in determining reproductive capability. These results suggested the presence of distinctive expression patterns in 6 weeks postpartum, correlated with cows’ reproductive capacity. Furthermore, we proposed the INHBA/INHA ratio as an indicator of calving-to-conception interval length.

MicroRNAome: Potential and Veritable Immunomolecular Therapeutic and Diagnostic Baseline for Lingering Bovine Endometritis

The bovine endometrium is a natural pathogen invasion barrier of the uterine tissues' endometrial epithelial cells that can resist foreign pathogen invasion by controlling the inflammatory immune response. Some pathogens suppress the innate immune system of the endometrium, leading to prolonged systemic inflammatory response through the blood circulation or cellular degradation resulting in bovine endometritis by bacterial endotoxins. The microRNA (miRNA) typically involves gene expression in multicellular organisms in post-transcription regulation by affecting both the stability and the translation of messenger RNA. Accumulated evidence suggests that miRNAs are important regulators of genes in several cellular processes. They are a class of endogenous non-coding RNAs, which play pivotal roles in the inflammatory response of reproductive diseases. Studies confirmed that miRNAs play a key regulatory role in various inflammatory diseases by mediating the molecular mechanism of inflammatory cytokines via signal pathways. It implicates some miRNAs in the occurrence of bovine endometritis, resorting to regulating the activities of some inflammatory cytokines, chemokine, differentially expressed genes, and protein through modulating of specific cellular signal pathways functions. This review dwells on improving the knowledge of the role of miRNAs involvement in inflammatory response as to early diagnosis, control, and prevention of bovine endometritis and consequently enlighten on the molecular improvement of the genes coded by various differentially expressed miRNA through the need to adopt recent genetic technologies and the development of new pharmaceutical preparations.

Gene expression in bovine endometrial cells and blood-derived neutrophils stimulated by uterine secretions

Uterine epithelial cells (UEC) and migrated polymorphonuclear cells (PMN) play important roles in the uterine defence against microbial infection. The aims of the present study were to investigate i) whether undiluted uterine secretions modulate the expression of genes associated with the innate immune response in UEC and PMN in vitro, ii) whether these changes differ between the two cell populations and iii) whether uterine secretions from cows with subclinical endometritis produce a different response to those from unaffected cows. Therefore, undiluted uterine secretions, cytobrush and biopsy samples were collected from bovine uteri at a local abattoir. All cows had calved at least 3 months prior to sample collection. Subclinical endometritis was diagnosed by cytology (≥5% polymorphonuclear neutrophils) and histology. The uteri were thereby retrospectively categorised as endometritis-positive (E-pos; n = 14), if either the cytology or the histology results were positive, or endometritis-negative (E-neg; n = 17), if both diagnostics were negative. Cultured UEC responded to secretions from E-pos and E-neg cows with an increased gene expression of CXC ligand (CXCL) 8 and interleukin (IL) 6 compared to incubation with control medium alone. PMN expressed significantly higher mRNA levels of CXCL5, CXCL8 and IL1B in response to supernatant from UEC incubated with secretions from both groups (E-pos and E-neg) compared to those incubated with control medium alone. Gene expression of IL10 in uterine epithelial cells remained comparable to the control in cells exposed to E-pos secretions and was 3.6 times lower in those exposed to E-neg secretions. These results demonstrate that the expression of genes associated with the innate immune response in UEC and indirectly also PMN is affected by uterine secretions in vitro. Depending on the target gene, these changes differ between the two cell populations. UEC exposed to uterine secretions from cows without subclinical endometritis produce lower levels of IL10 compared to those exposed to secretions from affected cows or control medium alone. Therefore, the model established in this study can be used as a valuable tool to further understand the contributions of the two cell populations to the coordinated immune response in the uterus.

Characterization of immunological, biochemical and inflammatory response of clinical and subclinical endometritis in ewes in the subtropics

Pluriparus Ossimi (n = 50) ewes were used to investigate the immune profile of the affected ewes to accurately diagnose clinical and subclinical endometritis and associations with biochemical variables. Ewes were slaughtered and animals were classified into control (no fertility problems), subclinical endometritis (SCE) and clinical endometritis (CE) groups based on pre-slaughter determinations of conception failure. Serum was collected from ewes to estimate concentrations of pro-inflammatory cytokines including interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and interleukin-8 (IL-8) as well as nitric oxide (NO) concentration. The results from immunological evaluations indicated there were greater (P < 0.001) serum concentrations of IL-6, IL-8, TNF-α and NO in ewes classified with SCE and CE as compared to ewes of the control group. Furthermore, values for concentrations of TNF-α were positively correlated with IL-6 and IL-8 concentrations in ewes of the SCE and CE groups. In ewes classified with CE and SCE there were greater (P < 0.01) concentrations of blood glucose, ALT, AST, urea and creatinine than in ewes of the control group. It is concluded that serum pro-inflammatory cytokines IL-6, IL-8, and TNF-α are diagnostic markers for CE and SCE in ewes and serve as a criterion for different inflammatory complications in ewes classified as having CE or SCE.

Quantifying the C-reactive protein concentrations of uterine lavage samples in postpartum dairy cows

Changes in the C-reactive protein (CRP) concentration, a non-specific diagnostic biomarker, in uterine lavage fluid and associations with cytological findings were examined following parturition in dairy cows. In postpartum Holstein dairy cows (n = 8), uterine lavage was performed at 3 and 6 weeks postpartum, and polymorphonuclear leukocyte (PMN) ratios to total cells (PMN:ALL) and to lymphocytes (PMN:LYM) and CRP concentrations were determined. Blood samples were collected to monitor the metabolic variables, and plasma CRP concentrations were quantified using samples collected at the same time as the uterine lavage occurred. A cytological examination was performed to determine PMN:ALL and PMN:LYM. The values for metabolic variables were within the normal range throughout the postpartum period. There was a correlation between the PMN:ALL and PMN:LYM, and both ratios were less (P < 0.05) at 6 than 3 weeks postpartum. The mean CRP concentration of the uterine lavage fluid was less at 6 (27.7 ± 9.6 ng/ml) than 3 weeks (60.8 ± 28.1 ng/ml) postpartum, whereas mean plasma CRP concentration was greater at 6 (287.4 ± 34.1 ng/ml) than 3 (254.8 ± 29.4 ng/ml) weeks postpartum. The results of the present study indicate the CRP concentration of uterine lavage fluid decreased in parallel with the frequency of PMN during uterine involution, which leads to the suggestion that uterine lavage fluid CRP concentration could be utilized as a local biomarker for evaluating uterine inflammation in cows.

Progesterone inhibits inflammatory response in E.coli- or LPS-Stimulated bovine endometrial epithelial cells by NF-κB and MAPK pathways

Progesterone suppresses the innate immune function of bovine endometrium, making the uterus susceptible to bacterial infection. The bovine endometrial epithelial cells (BEEC) are the first line of defense against bacteria, such as Escherichia coli (E.coli) that causes inflammation of endometrium through the recognition of lipopolysaccharide (LPS). The aim of this study was to investigate the effect of progesterone on the inflammatory response and its potential mechanism using E.coli- or LPS-induced BEEC. Concentrations of 1, 3 and 5 ng/mL progesterone were selected. The mRNA expressions of proinflammatory cytokines were determined using qPCR. The activations of NF-κB and MAPK pathways were detected by Western blot and immunofluorescence. An increase in the mRNA expression of IL-1β, IL-6, IL-8 and TNF-α was observed in BEEC treated with progesterone, LPS or E.coli alone. Progesterone inhibited the E.coli- or LPS-induced gene expression of these cytokines. Progesterone treatment alone showed little influence on NF-κB or MAPK pathway. In BEEC stimulated with E.coli or LPS, progesterone inhibited the phosphorylations of IκB, p65, ERK1/2, p38MAPK and JNK, and the translocation of p65 into the nucleus. These results suggested that progesterone has anti-inflammatory effect, which may be mediated by inhibiting NF-κB activation and MAPK phosphorylation in BEEC.

Effects of intra-uterine infusion of proteolytic enzymes on selected cytokine concentrations, uterine inflammation, and fertility in postpartum water buffalo cows with subclinical endometritis

The study was conducted to evaluate effects of intrauterine administration of proteolytic enzymes on endometrial inflammation and reproductive performance in postpartum water buffalo cows with subclinical endometritis (SCE). Cows (n = 38) with SCE (≥ 18 % PMN i.e.; polymorphonuclear cells) on day 21 postpartum (21 dpp), were allocated into treatment (TR; n = 19; intrauterine infusion of trypsin, chymotrypsin and papain in 20 ml normal saline on 21 dpp) and control (PC; n = 19; intrauterine administration 20 ml saline) groups. Cows without SCE (< 18 % PMN) were not treated and served as the negative control (NC; n = 30). Ultrasonography and sampling (endometrial cytology, uterine flushing, blood) were conducted on day 21 (before treatment) and 28 postpartum (28 dpp). The PMN % and uterine horn diameter were less on 28 dpp (compared with 21 dpp) in NC and TR group only. Cows with SCE had greater uterine concentrations of interleukin (IL)-1β, IL-8 and tumor necrosis factor (TNF)-α; but lesser IL-10 than NC group on 21 and 28 dpp. There were greater serum IL-1β and TNF-α concentrations on 28 dpp in cows with SCE than NC group. Uterine concentrations of IL-1β were less, whereas IL-6 was greater following enzymatic treatment. Proteolytic enzyme treatment did not result in improvement in pregnancy rate compared with the PC group; however, days to conception were less in TR compared with the other two groups. In conclusion, results indicated a reduction in endometrial inflammation and days nonpregnant after proteolytic enzyme treatment in buffalo cows with SCE.

Cortisol inhibits the Escherichia coli-induced endometrial inflammatory response through NF-κB and MAPK pathways in postpartum goats

Glucocorticoids have been widely used as anti-inflammatory therapies. The mechanisms of cortisol action in goat does with endometritis, however, have not been reported. The aim of this study was to investigate the mechanism of cortisol in modulation of effects of E. coli-induced endometritis in the does. Does (n = 24) were assigned to four groups (n = 6): control, E. coli, cortisol, and E. coli + cortisol groups. Does in the cortisol and E. coli + cortisol group were treated with cortisol from 3 days before E. coli inoculations occurred to 36 days post-partum. Does in the E. coli and inoculation groups were administered via intrauterine infusion E. coli O₅₅ (10⁹ CFU/mL) at 0 h. Physical indicators, macroscopic and microscopic changes in the endometrium, uterine secretion cytology and bacteriology were evaluated before (0 h) and at 6, 12, 24, 48, and 72 h after E. coli inoculation. The TLR4 and pro-inflammatory cytokine mRNA transcripts were detected using qPCR. The activations of NF-κB and MAPK signaling pathways were detected using Western blot procedures. As a result, cortisol inhibited the inflammatory response of does by reducing the clinical symptoms, morphological endometrial damage, % PMN in uterine secretions, relative abundance of inflammatory gene mRNA transcripts in the endometrium of does. Cortisol inhibited NF-κB activity by reducing MyD88 and IκB phosphorylation. Treatment with cortisol suppressed the phosphorylation of ERK1/2, p38MAPK, and JNK. These results indicate the anti-inflammatory effect of cortisol in the endometrium of does may be regulated by NF-κB and MAPK pathways.

Modulation of immune function in the bovine uterus peripartum

There is a high risk of clinical or subclinical reproductive tract disease in the postpartum period in dairy cows. An integrated process of adaptive events should occur synchronously, including a robust but well-regulated immune response in the uterus. Failure of this process may result in reproductive tract inflammatory disease. Up to half of postpartum dairy cows are affected by metritis, purulent vaginal discharge (PVD), or subclinical endometritis. After parturition there is damage to the birth canal, the superficial layer of the endometrium is naturally wounded, and essentially all dairy cows have bacterial contamination in the uterus. Neutrophils are the most abundant type of inflammatory cell and the main line of defence against infection in the uterus. A prompt influx of neutrophils is associated with uterine health. Avoidance of clinical disease (metritis and PVD) depends in large part on how effective the immune response is at limiting the burden and effects of bacterial pathogens, while the occurrence of subclinical endometritis is more a function of avoiding excessive or persistent inflammation. Glucose supply, hypocalcemia, lipid mobilization from body fat, ketosis, and the flux of pro-inflammatory cytokines influence immune response and change rapidly and variably among individual cows. Effective but well-regulated inflammatory response will be favoured by best management practices for transition cows, but specific interventions to modulate immune response to prevent uterine disease remain developmental.

Potential roles of neutrophils in maintaining the health and productivity of dairy cows during various physiological and physiopathological conditions: a review

Neutrophils represent the first line of innate immunity and are the most prominent line of cellular defence against invading microorganisms. On stimulation, they can quickly move through the walls of veins and into the tissues of the body to immediately attack or monitor the foreign antigens. Neutrophils are highly versatile and sophisticated cells which are endowed with highly sensitive receptor-based perception systems. They were traditionally classified as short-lived phagocytes actively involved during infection and inflammation, but recently, it has been seen that neutrophils are capable of detecting the presence of sperms during insemination as well as an implanting embryo in the female reproductive tract. These specialised phagocytes play a major role in tissue remodelling and wound healing, and maintain homeostasis during parturition, expulsion of placenta, folliculogenesis, corpus luteum formation and luteolysis. Here, we review the role played by neutrophils in maintaining homeostasis during normal and inflammatory conditions of dairy cattle. We have summarised the alteration in the expression of some cell adhesion molecules and cytokines on bovine neutrophils during different physiological and physiopathological conditions. Some emerging issues in the field of neutrophil biology and the possible strategies to strengthen their activity during the period of immunosuppression have also been discussed.

Effects of intrauterine infusion of bacterial lipopolysaccharides on the mammary gland inflammatory response in goats

This study aimed to determine if intrauterine-infused lipopolysaccharides (LPS) can be translocated to the mammary glands and induce an inflammatory response. Thirty-seven goats were divided into two experiments. Nineteen goats (control group, n = 9; LPS group, n = 10) were subjected to intravenous injection of LPS, and eighteen goats (control group, n = 8; LPS group, n = 10) were subjected to intrauterine infusion of LPS. Milk and blood samples were collected before and after the LPS challenge, to measure the blood leukocyte count (BLC), plasma LPS-binding protein (LBP), milk yield, milk somatic cell count (SCC), lactoferrin (LF), milk lactoperoxidase (LPO) activity, and pro- and anti-inflammatory cytokines in plasma and milk. Mammary gland tissues were collected from the parenchyma before and after the LPS challenge, for immunohistochemistry of LPS. In the intravenous injection experiment, the BLC (P < 0.001) and milk yield (P = 0.009) were lower, whereas the LF concentration (P < 0.001) and milk LPO activity (P < 0.001) were higher in the LPS group compared to that in the control group. LPS was detected in the mammary gland 3 and 24 h after intravenous injection of LPS. In the intrauterine infusion experiment, the mean concentrations of IL-1β and IL-6 in milk were higher in the LPS group compared to that in the control group (P = 0.004 and P = 0.017, respectively), whereas there were no changes in milk yield or SCC. LPS was detected in the connective tissues and interepithelial spaces of the alveoli of the mammary glands 24 h after intrauterine infusion of LPS. We conclude that intrauterine-infused LPS can be translocated to the mammary glands from the uterus, however, the amount of translocated LPS might not be enough to induce symptoms of clinical or subclinical mastitis.

Subclinical endometritis in estrual buffaloes: diagnosis, prevalence and impact on reproductive performance

The study evaluated the reliability of polymorphonuclear (PMN) cell count in endometrial cytology by cytobrush technique as a diagnostic for subclinical endometritis (SCE) at the time of estrus and its relationship with bacterial presence and fertility in buffaloes. Healthy pluriparous buffaloes (n = 115) were subjected to endometrial sampling by cytobrush technique (for cytology and bacterial isolation) and ultrasonography of genitalia prior to insemination at the time of spontaneous estrus. Buffaloes were inseminated at the same estrus and were confirmed for pregnancy by ultrasonography at day 40 post-insemination. Growth of aerobic bacteria was recorded in 26.1% (30/115) of estrual buffaloes. Bacteria of eight distinct genera (Staphylococcus spp., Bacillus spp., Proteus spp., Escherichia coli, Klebsiella spp., Streptococcus spp., Pseudomonas spp. and T. pyogenes) were isolated. Presence of bacterial infection was considered as the standard, against which PMN threshold for SCE was calculated by receiver operator curve (ROC). The PMN count of ≥ 5% with good sensitivity (66.7, 95% CI 50.9-81.4) and specificity (87.0%, 95% CI 78.0-94.6) with an overall high diagnostic accuracy (81.7%) for predicting SCE was obtained. Based on calculated PMN threshold, buffaloes were divided into subclinical endometritic (SCE; ≥ 5% PMNs) and control (< 5% PMNs) groups. Thirty-one buffaloes (27.0%, 31/115) had ≥ 5% PMNs in the endometrial cytology at estrus. Ultrasonographic evaluation showed that size of largest follicle, endometrial thickness, and uterine horn diameter did not differ significantly (P > 0.05) between the two groups. Significantly, lower conception rate (22.58 vs 36.90%, P < 0.05) for first artificial inseminations (AIs) and significantly higher number of AIs per pregnancy (2.81 ± 0.27 vs 1.75 ± 0.15, P < 0.05) were recorded in SCE compared to control group. The results indicated that cytobrush based endometrial cytology with 5% PMN cut-off value has a good accuracy for predicting subclinical endometritis at estrus in buffaloes.

Subclinical endometritis in dairy cattle is associated with distinct mRNA expression patterns in blood and endometrium

Cattle with subclinical endometritis (SCE) are sub-fertile and diagnosing subclinical uterine disease remains a challenge. The hypothesis for this study was that endometrial inflammation is reflected in mRNA expression patterns of peripheral blood leucocytes. Transcriptome profiles were evaluated in healthy cows and in cows with SCE using circulating white blood cells (WBC) and endometrial biopsy samples collected from the same animals at 45–55 days postpartum. Bioinformatic analyses of microarray-based transcriptional data identified gene profiles associated with distinct biological functions in circulating WBC and endometrium. In circulating WBC, SCE promotes a pro-inflammatory environment, whereas functions related to tissue remodeling are also affected in the endometrium. Nineteen differentially expressed genes associated with SCE were common to both circulating WBC and the endometrium. Among these genes, transcript abundance of immune factors C3, C2, LTF, PF4 and TRAPPC13 were up-regulated in SCE cows at 45–55 days postpartum. Moreover, mRNA expression of C3, CXCL8, LTF, TLR2 and TRAPPC13 was temporally regulated during the postpartum period in circulating WBC of healthy cows compared with SCE cows. This observation might indicate an advantageous modulation of the immune system in healthy animals. The transcript abundance of these genes represents a potential source of indicators for postpartum uterine health.

Characterization of circulating plasma proteins in dairy cows with cytological endometritis

Early diagnosis of endometritis in dairy cattle is currently requires invasive techniques and specialist expertise. The goal of this study is to utilize a gel-free mass-spectrometry based proteomics approach to compare the plasma proteome of dairy cattle with cytological endometritis to those without. Blood samples were collected from cows (N = 112) seven days postpartum (DPP). Plasma samples from a cohort of 20 animals with cytological endometritis (n = 10) and without (n = 10) as classified 21 DPP were selected for proteomic analysis. Differential abundances of proteins between the two animal groups were determined using both fold change (≥1.5 fold change) and statistical significance threshold (p < .05). A total of 181 non-redundant proteins were quantified, and 25 proteins were found with differential abundance. These include 4 binding protein alpha and mannose binding lectin 2 involved in immune responses. Differentially abundant proteins between the animals were then processed using PANTHER for gene ontology. Gene ontology included associations with innate immune processes, acute phase responses and immune regulation. A potential marker for disease identified here is the "uncharacterized protein G5E513," a protein previously defined by RNA-transcripts. These proteins may form the basis for endometritis prognosis, the development of which is proceeded by systemic changes in immune function. SIGNIFICANCE: Endometritis is a costly reproductive disease of lactating dairy cows that warrants timely diagnosis. We utilized a gel-free mass-spectrometry based proteomics approach to compare the plasma proteome of dairy cattle with cytological endometritis to those without, for the characterization of changes in the proteomic profile associated with uterine disease postpartum. Furthermore, we compared the plasma proteome of healthy and affected cows in the same physiological status of production to better understand the relationship between changes in expression of circulating proteins and to unravel essential biological mechanisms involved in bovine cytological endometritis.

Short communication: Proinflammatory gene expression relative to the collection technique of endometrial samples from cows with and without subclinical endometritis

Uterine inflammation negatively affects reproductive performance and is an important cause of infertility and subfertility in dairy cows. Several studies have investigated the use of gene expression in endometrial samples collected by biopsy or cytology to evaluate the inflammatory response of the cow uterus. This study aimed to compare the expression of the CCL5, CXCL8, IL6, and IL1B genes in the bovine endometrium according to the site of sample collection [caruncular (C) or intercaruncular (IC)], the collection method (biopsy or cytology), and the category of inflammation based on endometrial cytology (zero, medium, or high) in subclinical endometritis. The reproductive tracts of dairy cows were collected from a slaughterhouse, and punch-biopsy samples of endometrial tissues were obtained from both regions (C and IC). Endometrial cells from these regions were collected with the cytobrush technique and then used for the analysis of mRNA expression by quantitative PCR. After counting polymorphonuclear cells (PMN) by endometrial cytology, 20 uteri with an ovary at stage I (d 1-4 of estrous cycle) were categorized into 3 groups. Uteri with 0% PMN (n = 10) were assigned to group zero, uteri with 5 to 15% PMN (n = 5) to group medium (12.2 ± 1.6% PMN), and uteri with >15% PMN (n = 5) to group high (53.8 ± 32.9% PMN). All data were analyzed with 2-way ANOVA with Bonferroni multiple comparison post test. The results from gene transcripts demonstrated that the region (C or IC) of the endometrial biopsy had no influence on any of the degrees of inflammatory reaction observed. However, gene expression was more elevated in the endometrium of cows with greater inflammation compared with those without inflammation (CCL5, CXCL8, IL6, IL1B) and those with medium inflammation (CCL5, IL6). Expression of the genes evaluated did not differ between the endometrium without inflammation and with medium inflammation. However, in the high inflammation group, all genes were comparatively more expressed in samples collected by cytology relative to those derived from biopsies for both anatomical regions. In conclusion, gene expression did not differ between the C and IC tissue. Samples collected from animals with greater inflammation had greater gene expression than those with zero or medium inflammation. In addition, cytology samples had greater gene expression than biopsy samples in the high inflammation group.

Differential expression of bovine major acute phase proteins, cytokines and metabolic indicator genes in clinical endometritis cows

Among the uterine diseases, clinical endometritis (CE) is a major challenge to livestock farming as it causes sub- or infertility problems in dairy animals. The aim of this study was to evaluate the expression of cytokines (IL- 1β, TNF-α, IL-6, and IL-8), acute phase proteins [APPs; haptoglobin (Hp), serum amyloid A (SAA) and alpha-1 acid glycoprotein (AGP)] and energy indicators [leptin and insulin-like growth factor (IGF)-1] genes in uterine tissue of CE affected cows. The uterine biopsy from CE cows (4) and non-endometritis cows (4) was processed for quantitative real-time PCR to study the mRNA expression of these innate immune molecules. We observed that mRNA expression of SAA, IL-1β, IL-8 and leptin genes were significantly up-regulated while, TNF-α and IGF-I genes were significantly down-regulated in CE cows. It can be concluded that bovine APPs, cytokines and energy indicators genes are differentially expressed in CE affected cows.

Characterization of cytokine gene expression in uterine cytobrush samples of non-endometritic versus endometritic postpartum dairy cows

To better understand uterine inflammation in postpartum dairy cows we collected sequential cytobrush samples at 29-35 and at 49-55 d in milk (DIM). Based on the uterine cytology, cows were classified as Non-endometritic (n = 23; <18% neutrophils) or Endometritic (n = 12; ≥18% neutrophils) at 29-35 DIM and Non-endometritic (n = 17; <10% neutrophils) or Endometritic (n = 9; ≥10% neutrophils) at 49-55 DIM. Cows defined as Sham Controls (n = 6) were examined by vaginoscopy at 29-35 DIM and identified as Non-endometritic (<10% neutrophils) at 49-55 DIM. Cytokine gene expression in cytobrush samples was assessed using qRT-PCR. Sham Controls did not differ significantly (P > 0.17) from Non-endometritic cows at 49-55 DIM and these data were combined (n = 23). Uterine cytology-based classification using the aforementioned thresholds effectively separated cows into groups with Endometritic cows having significantly higher expression of pro-inflammatory (interleukin (IL)-1α, IL-1β, IL-6, IL-8, IL-17A CSF-1; P < 0.01) and regulatory (IL-1RA and IL-10; P < 0.03) cytokines, relative to Non-endometritic cows. Furthermore, Non-endometritic cows showed a significant decline (P < 0.03) in the expression of pro-inflammatory (IL-1α, IL-6, IL-8) and regulatory (IL-10) cytokine genes as the postpartum period progressed; whereas Endometritic cows exhibited a sustained elevation in transcript abundance throughout the sample period for both pro-inflammatory and regulatory cytokine genes. Expression of transforming growth factor (TGF) genes was more complex with TGF-β3 expression significantly (P < 0.01) lower at 29-35 DIM and TGF-β1 gene expression significantly (P < 0.03) increased at 49-55 DIM in Endometritic versus Non-endometritic cows. Expression of TGF-β2 gene was 2.7-fold higher (P < 0.01) at 29-35 DIM in cows that remained Endometritic when compared to cows recovering by 49-55 DIM. Some Non-endometritic cows (n = 4) at 29-35 DIM were reclassified as Endometritic at 49-55 DIM. The sampling procedures at 29-35 DIM did not alter either the cellular response (P > 0.43) or cytokine gene expression (P > 0.17) at 49-55 DIM. In conclusion, normal uterine involution is characterized by a progressive decline in pro-inflammatory and regulatory cytokine gene expression, while cows with endometritis show a dysregulated inflammatory process characterized by a sustained elevation in pro-inflammatory and regulatory cytokine gene expression. This analysis also shows that decreased TGF-β2 gene expression at 29-35 DIM may be an indicator of recovery from endometritis.

Saikosaponin A Inhibits LPS-Induced Endometritis in Mice Through Activating Nrf2 Signaling Pathway

Saikosaponin A (SSA) is the major triterpenoid glycoside isolated from Bupleurum falcatum. In this study, we reported the protective effects and mechanism of SSA on lipopolysaccharide (LPS)-induced endometritis in mice. The pathological changes and myeloperoxidase (MPO) activity of uterus tissues were evaluated by hematoxylin and eosin (H&E) staining and MPO detection kit. Inflammatory cytokines TNF-α, IL-1ß, and IL-6 production were detected by ELISA. The expression of protein was measured by western blot analysis. The results showed that SSA administration inhibited inflammatory cell infiltration as confirmed by the decreased MPO activity. LPS-induced uterus histological changes were also suppressed by SSA. Meanwhile, LPS-induced TNF-α, IL-1ß, and IL-6 production were reduced by SSA administration. The phosphorylation levels of nuclear factor kappa B (NF-κB) and inhibitor of kappa B (IκBα) induced by LPS were inhibited by SSA. In addition, the expression of nuclear factor E2-related factor 2 (Nrf2) and heme oxygenase (HO-1) were upregulated by SSA in a concentration-dependent manner. These results provide evidence that SSA protects against LPS-induced endometritis through inhibiting inflammatory response. SSA may be used as a potential therapeutic agent for the treatment of endometritis.

Tolerance and Innate Immunity Shape the Development of Postpartum Uterine Disease and the Impact of Endometritis in Dairy Cattle

Bacteria are ubiquitous in the bovine uterus after parturition, but 50 years ago, cows tolerated these bacteria and few animals developed uterine disease. Now, up to 40% of dairy cattle develop postpartum uterine disease. Uterine disease causes infertility by compromising the function of not only the endometrium but also the ovary. Animals defend themselves against pathogens using tolerance and resistance mechanisms. Tolerance is the ability to limit the disease severity induced by a given pathogen burden. Resistance is the ability to limit the pathogen burden and is usually the function of immunity. Endometrial cells contribute to tolerance and have roles in innate immunity and the inflammatory response to pathogens. However, failures in endometrial tolerance and the character of the inflammatory response shape postpartum uterine disease. We propose that uterine health is more dependent on the ability of the endometrium to tolerate pathogens than the ability to resist invading bacteria.

Uterine inflammation and fertility of beef cows subjected to timed AI at different days postpartum

The aim of this study was to evaluate the uterine health and fertility of postpartum beef cows subjected to timed AI (TAI) protocols at different days from calving. Lactating Nelore cows (Bos indicus; n = 244) were used in this study. The TAI protocols were initiated between 20 and 60 days postpartum (DPP). Cows were subjected to an estradiol-progesterone based TAI protocol. The cows were divided into three groups according to the days postpartum at the time the hormonal treatment was initiated: 1) Early (n = 64), cows between 20 and 30 DPP; 2) Middle (n = 115), cows between 31 and 45 DPP; and 3) Late (n = 65), cows between 46 and 60 DPP. At Day 0 of the protocol, endometrial cytobrush samples were collected. Slides for polymorphonuclear (PMN) cell counting were prepared and cytobrush was used for RNA extraction and analysis of relative abundance of il1, il6, il8, and tnf mRNA. Cows from the Early group had less (P < 0.05) pregnancies per AI (P/AI) than cows from Middle and Late groups; 29.7% (19/64), 45.2% (52/115), and 52.31% (34/65), respectively. Accordingly, the Early group had a greater (P < 0.05) proportion of PMN cells in the uterus than Middle and Late groups; 9.0%, 3.8%, and 2.2%, respectively. Relative abundances of il1 and il8 mRNA were greater (P < 0.05) in the Early group than Middle and Late groups. These results indicate that beef cows subjected to TAI protocols early postpartum (< 30 DPP) are less likely to become pregnant, which is associated with increased inflammation and relative abundance of mRNA for the proinflammatory cytokines il1 and il8.

The Potential Therapeutic Role of miR-223 in Bovine Endometritis by Targeting the NLRP3 Inflammasome

Bovine endometritis affects milk production and reproductive performance in dairy cows and causes serious economic loss. The underlying molecular mechanisms or signaling pathways of bovine endometritis remain unclear. In this study, we attempted to determine the expression mechanism of mir-223 in endometritis of dairy cows and evaluate its potential therapeutic value. We first confirmed that there was an increased level of miR-223 in endometritis, and then, an LPS-induced bovine endometrial epithelial cell (BEND) line was used to mimic the inflammatory model in vitro. Our data showed that activation of NF-κB promoted the transcription of miR-223, thus inhibiting activation of the inflammatory mediator NLRP3 and its mediation of IL-1β production to protect against inflammatory damage. Meanwhile, in vivo studies showed that inhibition of mir-223 resulted in an enhanced pathology of mice during LPS-induced endometritis, while overexpression of mir-223 attenuated the inflammatory conditions in the uterus. In summary, our study highlights that miR-223 serves both to constrain the level of NLRP3 activation and to act as a protective factor in the inflammatory response and thus provides a future novel therapeutic modality for active flares in cow endometritis and other inflammatory diseases.

Bacterial presence and fertility in subclinical endometritic buffaloes at oestrus

Study evaluated the diagnosis of subclinical endometritis (SCE) at the time of oestrus in relation to uterine bacterial contamination and fertility in buffaloes (Bubalus bubalis). Normal cyclic healthy buffaloes (115) presented for insemination at spontaneous oestrus were diagnosed (by endometrial cytology) for SCE and divided into control (<5% PMN) and SCE (≥5% PMNs) groups. The prevalence of 22.61% for SCE was recorded. Significantly higher proportion of buffaloes were infected in SCE (65.4 vs 21.3%) than in control group. The seven different bacteria (Staphylococcus spp., Bacillus spp., Proteus spp., Escherichia coli, Klebsiella spp., Streptococcus spp. and Pseudomonas spp.) in both the groups with T. pyogenes only in SCE group were isolated. The presence of SCE as well as bacteria recorded a detrimental effect on fertility, with significantly lower conception rate (23.08 vs 37.08%) in SCE and tendency for higher number of services per conception in buffaloes with infected uteri, compared to their healthy counterparts. A differential trend for antibiotic sensitivity to the bacterial isolates was recorded.

Influence of intrauterine administration of Lactobacillus buchneri on reproductive performance and pro-inflammatory endometrial mRNA expression of cows with subclinical endometritis

Potential beneficial effects of lactic acid bacteria on the genital health of cows become of particular interest when considering the importance of an optimal uterine health status for the success of breeding in dairy farming. Therefore, the aim of the present study was to analyse the influence of an intrauterine administration of the Lactobacillus buchneri DSM 32407 on reproductive performance, uterine health status, endometrial mRNA expression of pro-inflammatory factors of cows with signs of subclinical endometritis (SCE). L. buchneri DSM 32407 (n = 56; [LAC]) or a placebo (n = 60; [PLA]) was administered on day 24–30 postpartum. Endometrial cytobrush samples of cows with SCE were taken before the administration and at three following weeks (n = 16 cows each for LAC/SCE and PLA/SCE). A higher proportion of cows of the LAC and LAC/SCE group was pregnant after the first service and median days to conception for cows pregnant on day 200 pp were shorter. Three weeks after the administration, the endometrial mRNA expression of CXCL1/2, CXCL3, CXCR2, IL1B, IL8 and PTPRC was lower in the LAC/SCE group compared with the PLA/SCE group. These findings suggest that the presence of L. buchneri DSM 32407 contributes to a uterine environment that results in a better reproductive performance.

Increased mRNA expression of selected pro-inflammatory factors in inflamed bovine endometrium in vivo as well as in endometrial epithelial cells exposed to Bacillus pumilus in vitro

Endometrial epithelium plays a crucial role in the first immune response to invading bacteria by producing cytokines and chemokines. The aim of this study was to investigate the first inflammatory response of the endometrium in vivo and in vitro. Gene expression of several pro-inflammatory factors and Toll-like receptors (TLR2, -4, -6) was determined in endometrial cytobrush samples obtained from healthy cows and cows with clinical or subclinical endometritis. Endometrial epithelial cells were co-cultured with an isolated autochthonous uterine bacterial strain Bacillus pumilus. Total RNA was extracted from in vivo and in vitro samples and subjected to real-time reverse transcription polymerase chain reaction. CXC ligands (CXCL) 1/2 and CXC chemokine receptor (CXCR) 2 mRNA expression was higher in cows with subclinical endometritis and CXCL3 mRNA expression was higher in cows with clinical endometritis compared with healthy cows. B. pumilus induced cell death of epithelial cells within 24h of co-culturing. The presence of B. pumilus resulted in significantly higher mRNA expression of interleukin 1α (IL1A), IL6, IL8, CXCL1-3 and prostaglandin-endoperoxide synthase 2 in co-cultured cells compared with untreated controls. The maximum increase was mainly detected after 2h. These results support the hypothesis that bacterial infection of endometrial cells might induce prompt synthesis of pro-inflammatory cytokines resulting in a local inflammatory reaction.

Cortisol inhibits NF-κB and MAPK pathways in LPS activated bovine endometrial epithelial cells

The bovine uterus is subject to infection after calving, which may lead to endometritis. Elevated cortisol levels have been observed in postpartum cattle. However, the role of cortisol in the inflammatory response of the uterus has not been reported. The aim of this study was to investigate the anti-inflammatory effects of cortisol on lipopolysaccharide (LPS)-induced primary bovine endometrial epithelial cells (BEECs). BEECs were treated with various concentrations of cortisol (5, 15 and 30 ng/mL) in the presence of LPS. The mRNA expression of TLR4 and proinflammatory cytokines was measured with qPCR. The activation of NF-κB and MAPK signalling pathways was detected with Western blotting and immunofluorescence. Cortisol induced the down-regulation of the mRNA expression of toll-like receptor 4 (TLR4) and proinflammatory cytokines, including interleukin (IL)-1β, IL-6, IL-8, tumour necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2) and inducible NO synthase (iNOS). Cortisol inhibited the activity of nuclear factor-κB (NF-κB) via blocking the phosphorylation and degradation of IκB. Cortisol suppressed the phosphorylation of mitogen-activated protein kinase (MAPK), including extracellular signal-regulated kinase (ERK1/2), p38MAPK and c-Jun N-terminal kinase/stress-activated protein kinase (JNK). These results demonstrated that cortisol may exert its anti-inflammatory actions by regulating NF-κB activation and MAPK phosphorylation.

Insights into bovine endometritis with special reference to phytotherapy

Postpartum reproductive disorders cause heavy economic losses in dairy sector. Uterine infections include endometritis, metritis, mucometra, and pyometra. Postpartum endometritis in dairy cows has been defined as inflammation of endometrium occurring 21 days or more after parturition without systemic signs of illness. The treatment of endometritis with antimicrobials has met with varying degrees of success, inconsistent recovery rate, high cost of treatment, milk disposal, emergence of microbial resistance, and reduced phagocytic activity of polymorphonuclear leukocytes In our country, around 20,000 medicinal plant species have been recorded, but more than 500 traditional communities use about 800 plant species for curing different diseases. Many herbs such as garlic, neem, ashwagandha, and turmeric have been tried for the treatment of endometritis in cows with a good success.

Endometrial biopsy in Bos indicus beef heifers

An endometrial biopsy allows for a comprehensive assessment of the uterine environment of a breeding female. Although routine in mares, devices used for endometrial biopsies are impracticable in heifers due to the size and structure of the cervix. This report describes the use of a human bronchoscopy biopsy device (Karl Storz^® 10366L) for collection of endometrial biopsies in Bos indicus beef heifers. The Storz^® device is smaller and thinner and enabled the collection of an endometrial biopsy in 86% of heifers (n = 44/51). The biopsied tissue was of good quality and suitable for transcriptomic assessment of the endometrium, with total RNA yield and RNA integrity number (RIN) averaging 1.3 μg (range 0.4-5.3 μg) and 7.4 (range 5.7-8.4), respectively.