Exposure to endotoxin during estrus alters the timing of ovulation and hormonal concentrations in cows

127

100

Mammalian reproductive physiology and the development of viviparity co-evolved with inflammation and immunity over millennia. Many inflammatory mediators contribute to paracrine and endocrine signalling, and the maintenance of tissue homeostasis in the female reproductive tract. However, inflammation is also a feature of microbial infections of the reproductive tract. Bacteria and viruses commonly cause endometritis, perturb ovarian follicle development and suppress the endocrine activity of the hypothalamus and pituitary in cattle. Innate immunity is an evolutionary ancient system that orchestrates host cell inflammatory responses aimed at eliminating pathogens and repairing damaged tissue. Pattern recognition receptors on host cells bind pathogen-associated molecular patterns and damage-associated molecular patterns, leading to the activation of intracellular MAPK and NFkB signalling pathways and the release of inflammatory mediators. Inflammatory mediators typically include the interleukin cytokines IL1b and IL6, chemokines such as IL8, interferons and prostaglandins. This review outlines the mechanisms of inflammation and innate immunity in the bovine female reproductive tract during health and disease condition.

Section: Host Responses In the Brain Associated With Uterine Diseasementioning

confidence: 56%

Innate immunity and inflammation of the bovine female reproductive tract in health and disease

Sheldon¹,

Cronin²,

Healey³

et al. 2014

127

100

“…LPS was found in the follicular fluid of such animals, likely additionally contributing to the delay in ovulation (Sheldon et al 2009b). Similar effects associated with a delayed luteinizing hormone surge and the resulting postponed ovulation were observed after intravenous or intramammary administration of LPS in cows (Lavon et al 2008). Furthermore, intravenous treatment with LPS transiently suppressed progesterone (P 4 ) secretion by the bovine corpus luteum (CL) and increased plasma concentrations of prostaglandin (PG) F 2a metabolites (PGFM) (Herzog et al 2012).…”

Section: Introductionmentioning

confidence: 79%

“…A systemic inflammatory response due to bovine metritis and mastitis is often associated with the presence of lipopolysaccharide (LPS), the endotoxin of gramnegative bacteria (Bannerman et al 2004, Williams et al 2005. There is increasing evidence that, at least in part, Escherichia coli LPS causes infertility by interfering with ovarian function (Suzuki et al 2001, Lavon et al 2008). …”

Section: Introductionmentioning

confidence: 99%

LPS-mediated effects and spatio-temporal expression of TLR2 and TLR4 in the bovine corpus luteum

Lüttgenau¹,

Herzog²,

Strüve³

et al. 2016

When given intravenously (iv), lipopolysaccharide (LPS) transiently suppresses the structure and function of the bovine corpus luteum (CL). This is associated with increased release of prostaglandin (PG) F 2a metabolite. The underlying regulatory mechanisms of this process remain, however, obscure. Therefore, the aims of this study were: i) to investigate the expression of the LPS receptor toll-like receptor 4 (TLR4) and 2 (TLR2) in the bovine CL during early, mid-and late luteal phases; and ii) to further dissect the mechanisms of LPS-mediated suppression of luteal function. As revealed by semi-quantitative qPCR and immunohistochemistry, both receptors were detectable throughout the luteal lifespan. Their mRNA levels increased from the early toward the mid-luteal phase; no further changes were observed thereafter. The TLR4 protein seemed more highly represented than TLR2. The cellular localization of TLRs was in blood vessels; weaker signals were observed in luteal cells. Additionally, cows were treated either with LPS (iv, 0.5 mg/kg BW) or with saline on Day 10 after ovulation. Samples were collected 1200 h after treatment and on Day 10 of the respective subsequent (untreated) cycle. The mRNA expression of several possible regulatory factors was investigated, revealing the suppression of PGF 2a receptor (PTGFR), STAR protein and 3b-hydroxysteroid dehydrogenase, compared with controls and subsequent cycles. The expression of TLR2 and TLR4, interleukin 1a (IL1A) and 1b (IL1B) and of PGF 2a and PGE 2 synthases (HSD20A and mPTGES respectively) was increased. The results demonstrate the presence of TLR2 and TLR4 in the bovine CL, and implicate their possible involvement in the deleterious effects of LPS on its function.

“…Intramammary injections were performed following careful cleaning of the teat, using a sterile syringe mounted with a sterile adapter via the teat canal into the gland, as described previously (Lavon et al 2008). Clinical symptoms such as swelling, rigidity, and high sensitivity of the udder were checked frequently throughout the day of administration.…”

Section: Induction Of Mastitismentioning

confidence: 99%

Effects of Escherichia coli- and Staphylococcus aureus-induced mastitis in lactating cows on oocyte developmental competence

Asaf

Leitner²,

Furman³

et al. 2014

Mastitis is associated with decreased fertility in dairy cows. In the current study, we created an experimental model to simulate shortterm mastitis by a single intramammary administration of Gram-negative endotoxin of Escherichia coli origin (GK), or Gram-positive toxin of Staphylococcus aureus origin (GC), to examine the effect of mastitis on oocyte developmental competence. Healthy Holstein cows were synchronized, and follicular fluid (FF) of cows treated with GC or GK and of uninfected cows (controls) was aspirated from the preovulatory follicles by transvaginal ultrasound procedure. The aspirated FF was used as maturation medium for in vitro embryo production. The distribution of matured oocytes into different cortical granule classes and meiotic stages was affected by GK administration (P!0.05) but not by GC administration. The proportion of oocytes that cleaved to two-and four-cell stage embryos (44 h postfertilization) was lower in both GC and GK groups than in controls (P!0.05). Blastocyst formation rate (7-8 days postfertilization) was lower in the GK group (P!0.05) and numerically lower in the GC group compared with their uninfected counterparts. The total cell number in blastocysts did not differ among groups; however, the apoptotic index was higher in the GC group (P!0.05), but not in the GK group, relative to controls. Examining mRNA relative abundance in oocytes and early embryos revealed mastitis-induced alterations in PTGS2 (COX2), POU5F1, and HSF1 but not in SLC2A1 (GLUT1) or GDF9. Results indicate a differential disruptive effect of mastitis induced by GK and GC on oocyte developmental competence in association with alterations in maternal gene expression.