Oestrous cycle-dependent equine uterine immune response to induced infectious endometritis

Abstract

Infectious endometritis is a major cause of reduced pregnancy rates in horses. The objectives of this study were to establish a timeline of the innate immune response in the uterus of healthy horses and to investigate the oestrous cycle effect on this. Endometrial biopsies were collected from five horses before and at 3, 12, 24, 48 and 72 h after inoculation of Escherichia coli, once in oestrus and once in dioestrus. They were analysed by quantitative real-time PCR, microbiology and histology. Neutrophil numbers increased from very low levels in the absence of inflammation to severe neutrophilia 3 h after inoculation. The concentrations of mRNAs for Toll-like receptor (TLR)2, TLR4, NOD-like receptor NLRC5, tissue inhibitor of metallopeptidases 1 (TIMP1) and chemokines CCL2, CXCL9, CXCL10 and CXCL11 were all increased 3 h after inoculation of E. coli compared to levels detected prior to inoculation. Chemokine mRNA levels remained elevated for 48 h. Concentrations of mRNAs for the antimicrobial peptides equine β-defensin 1 (EBD1), lysozyme, secretory leukoprotease inhibitor (SLPI), lipocalin 2 (LCN2), lactoferrin and uteroferrin were increased between 3 and 12 h post inoculation. The gene for secreted phospholipase A2 (sPLA2) was expressed constitutively. P19 uterocalin mRNA levels were higher in dioestrus than in oestrus over the first 24 h of inflammation. Neutrophils and many innate immune genes responded rapidly to the introduction of E. coli into the uterus, while the oestrous cycle stage had only a relatively minor effect on the response to E. coli. This study has delineated a useful model of innate immunity in infectious endometritis of healthy animals.Electronic supplementary materialThe online version of this article (doi:10.1186/s13567-016-0398-x) contains supplementary material, which is available to authorized users.

A comparison of the uterine proteome of mares in oestrus and dioestrus

“…In agreement with other studies (Crossett, Allen, & Stewart, ; Hayes et al, ), P19/uterocalin (also known as concepticalin, equicalin and lipocalin P19) was found to be more abundant in endometrial flush fluid samples from mares in dioestrus. Studies on endometrial mRNA expression of uterocalin in mares have also indicated greater expression in dioestrus than in oestrus (Marth et al, ). Uterocalin is a P 4 ‐dependent protein that is secreted by endometrial glands both in dioestrus and early pregnancy (Crossett et al, ).…”

“…have also indicated greater expression in dioestrus than in oestrus (Marth et al, 2016(Marth et al, , 2018. Uterocalin is a P 4 -dependent protein that is secreted by endometrial glands both in dioestrus and early pregnancy (Crossett et al, 1996).…”

Interleukin-17 pathway activation inEquus caballussupporting limb laminitis

“…Given the high expression of ß defensin 4 (human gene name DEFB4 ) in IL-17-treated human keratinocytes [34], we used qPCR to examine relative expression levels of DEFB4B mRNA in SLL samples compared to non-laminitic controls (Fig 4). Note that the equine DEFB4B sequence was formerly identified as ß defensin 1 [61]. As shown in Fig 4A, DEFB4B expression was upregulated at all disease stages compared to the non-laminitic controls.…”

Emerging Roles for NLRC5 in Immune Diseases

“…In addition, Marth et al found that the expression of the NLRC5 increased significantly within 3 hours in response to the introduction of E. coli. And this finding also indicated that the introduction of E. coli into the uterus of healthy animal has an effect on inducing inflammation, which was an effective model of innate immunity as well (Marth et al, 2016). Moreover, numerous studies have provided evidence that common variations in the NLR genes were highly correlated to the incidence of intestinal inflammation as well as susceptibility to cancer (Ogura et al, 2001; Villani et al, 2009; Kutikhin, 2011; Jostins et al, 2012).…”