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Inflammatory responses to induced infectious endometritis in mares resistant or susceptible to persistent endometritis.

Christoffersen M, Woodward E, Bojesen AM, Jacobsen S, Petersen MR, Troedsson MH, Lehn-Jensen H - BMC Vet. Res. (2012)

Bottom Line: Compared to levels in a control biopsy (obtained in the subsequent estrous), resistant mares showed an up-regulation of IL-1β, IL-6, IL-8 and TNF-α at 3 h after E. coli inoculation, while susceptible mares showed increased gene expression of IL-6 and IL-1ra.Susceptible mares had a significant lower gene expression of TNF-α,IL-6 and increased expression of IL-1ra 3 h after E. coli inoculation compared to resistant mares.Susceptible mares showed a sustained and prolonged inflammatory response with increased gene expression levels of IL-1β, IL-8, IL-1ra and IL-1β:IL-1ra ratio throughout the entire study period (72 h), whereas levels in resistant mares returned to estrous control levels by 12 hours.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Dyrlaegevej 68, Frederiksberg, Copenhagen DK-1870, Denmark. metc@life.ku.dk

ABSTRACT

Background: The objective of the study was to evaluate the gene expression of inflammatory cytokines (interleukin [IL]-1β, IL-6, IL-8, IL-10, tumor necrosis factor [TNF]-α, IL-1 receptor antagonist [ra] and serum amyloid A (SAA) in endometrial tissue and circulating leukocytes in response to uterine inoculation of 105 colony forming units (CFU) Escherichia coli in mares. Before inoculation, mares were classified as resistant or susceptible to persistent endometritis based on their uterine inflammatory response to infusion of 109 killed spermatozoa and histological assessment of the endometrial quality. Endometrial biopsies were obtained 3, 12, 24 and 72 hours (h) after bacterial inoculation and blood samples were obtained during the 7 day period post bacterial inoculation. Expression levels of cytokines and SAA were determined by quantitative real-time reverse transcriptase PCR (qRT-PCR).

Results: Compared to levels in a control biopsy (obtained in the subsequent estrous), resistant mares showed an up-regulation of IL-1β, IL-6, IL-8 and TNF-α at 3 h after E. coli inoculation, while susceptible mares showed increased gene expression of IL-6 and IL-1ra. Susceptible mares had a significant lower gene expression of TNF-α,IL-6 and increased expression of IL-1ra 3 h after E. coli inoculation compared to resistant mares. Susceptible mares showed a sustained and prolonged inflammatory response with increased gene expression levels of IL-1β, IL-8, IL-1ra and IL-1β:IL-1ra ratio throughout the entire study period (72 h), whereas levels in resistant mares returned to estrous control levels by 12 hours. Endometrial mRNA transcripts of IL-1β and IL-1ra were significantly higher in mares with heavy uterine bacterial growth compared to mares with no/mild growth.All blood parameters were unaffected by intrauterine E. coli infusion, except for a lower gene expression of IL-10 at 168 h and an increased expression of IL-1ra at 48 h observed in susceptible mares compared to resistant mares.

Conclusions: The current investigation suggests that endometrial mRNA transcripts of pro-inflammatory cytokines in response to endometritis are finely regulated in resistant mares, with initial high expression levels followed by normalization within a short period of time. Susceptible mares had a prolonged expression of pro-inflammatory cytokines, supporting the hypothesis that an unbalanced endometrial gene expression of inflammatory cytokines might play an important role in the pathogenesis of persistent endometritis.

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mRNA transcripts of endometrial a) IL-1β, b) IL-6, c) IL-8, d) TNF-α, e) SAA, f) IL-10, g) IL-1ra and h) IL-1β:IL-1ra in mares after intrauterine infusion of E. coli. The gene expressions are normalized to β-actin and displayed as n-fold change to estrous baseline levels (mean ± sem). Asteriks indicate significant differences between resistant (white bars) and susceptible (grey bars) mares. *p < 0.05. Different letters above the bars indicate significant differences between the time points within the group of mares (p < 0.05).
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Figure 2: mRNA transcripts of endometrial a) IL-1β, b) IL-6, c) IL-8, d) TNF-α, e) SAA, f) IL-10, g) IL-1ra and h) IL-1β:IL-1ra in mares after intrauterine infusion of E. coli. The gene expressions are normalized to β-actin and displayed as n-fold change to estrous baseline levels (mean ± sem). Asteriks indicate significant differences between resistant (white bars) and susceptible (grey bars) mares. *p < 0.05. Different letters above the bars indicate significant differences between the time points within the group of mares (p < 0.05).

Mentions: Susceptible mares showed increased levels of IL-1β 24 h (10-fold, p = 0.020), 72 h (10-fold, p = 0.02), and IL-8 at 72 h (13-fold, p = 0.0024) (Figure 2a, c) after E. coli infusion compared to resistant mares. The expression of IL-1ra was significantly increased in susceptible versus resistant mares at all time points (range: 6-20 fold, p < 0.05) (Figure 2g). Susceptible mares showed immediately (3 h) after inoculation a significantly lower expression of IL-6 (15-fold, p = 0.02) and TNF-α (9-fold, p = 0.015), but no difference at 12, 24 or 72 h (Figure 2b, d). Susceptible mares had a decreased ratio of IL1β:IL-1ra immediately after E. coli inoculation (3 h) (4-fold, p = 0.05), but an increased ratio was observed at the end of the study period (72 h) (4-fold, p = 0.05) compared to resistant mares (Figure 2h). No significant difference in endometrial mRNA transcripts for SAA between the two groups was observed (Figure 2e).


Inflammatory responses to induced infectious endometritis in mares resistant or susceptible to persistent endometritis.

Christoffersen M, Woodward E, Bojesen AM, Jacobsen S, Petersen MR, Troedsson MH, Lehn-Jensen H - BMC Vet. Res. (2012)

mRNA transcripts of endometrial a) IL-1β, b) IL-6, c) IL-8, d) TNF-α, e) SAA, f) IL-10, g) IL-1ra and h) IL-1β:IL-1ra in mares after intrauterine infusion of E. coli. The gene expressions are normalized to β-actin and displayed as n-fold change to estrous baseline levels (mean ± sem). Asteriks indicate significant differences between resistant (white bars) and susceptible (grey bars) mares. *p < 0.05. Different letters above the bars indicate significant differences between the time points within the group of mares (p < 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3368729&req=5

Figure 2: mRNA transcripts of endometrial a) IL-1β, b) IL-6, c) IL-8, d) TNF-α, e) SAA, f) IL-10, g) IL-1ra and h) IL-1β:IL-1ra in mares after intrauterine infusion of E. coli. The gene expressions are normalized to β-actin and displayed as n-fold change to estrous baseline levels (mean ± sem). Asteriks indicate significant differences between resistant (white bars) and susceptible (grey bars) mares. *p < 0.05. Different letters above the bars indicate significant differences between the time points within the group of mares (p < 0.05).
Mentions: Susceptible mares showed increased levels of IL-1β 24 h (10-fold, p = 0.020), 72 h (10-fold, p = 0.02), and IL-8 at 72 h (13-fold, p = 0.0024) (Figure 2a, c) after E. coli infusion compared to resistant mares. The expression of IL-1ra was significantly increased in susceptible versus resistant mares at all time points (range: 6-20 fold, p < 0.05) (Figure 2g). Susceptible mares showed immediately (3 h) after inoculation a significantly lower expression of IL-6 (15-fold, p = 0.02) and TNF-α (9-fold, p = 0.015), but no difference at 12, 24 or 72 h (Figure 2b, d). Susceptible mares had a decreased ratio of IL1β:IL-1ra immediately after E. coli inoculation (3 h) (4-fold, p = 0.05), but an increased ratio was observed at the end of the study period (72 h) (4-fold, p = 0.05) compared to resistant mares (Figure 2h). No significant difference in endometrial mRNA transcripts for SAA between the two groups was observed (Figure 2e).

Bottom Line: Compared to levels in a control biopsy (obtained in the subsequent estrous), resistant mares showed an up-regulation of IL-1β, IL-6, IL-8 and TNF-α at 3 h after E. coli inoculation, while susceptible mares showed increased gene expression of IL-6 and IL-1ra.Susceptible mares had a significant lower gene expression of TNF-α,IL-6 and increased expression of IL-1ra 3 h after E. coli inoculation compared to resistant mares.Susceptible mares showed a sustained and prolonged inflammatory response with increased gene expression levels of IL-1β, IL-8, IL-1ra and IL-1β:IL-1ra ratio throughout the entire study period (72 h), whereas levels in resistant mares returned to estrous control levels by 12 hours.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Dyrlaegevej 68, Frederiksberg, Copenhagen DK-1870, Denmark. metc@life.ku.dk

ABSTRACT

Background: The objective of the study was to evaluate the gene expression of inflammatory cytokines (interleukin [IL]-1β, IL-6, IL-8, IL-10, tumor necrosis factor [TNF]-α, IL-1 receptor antagonist [ra] and serum amyloid A (SAA) in endometrial tissue and circulating leukocytes in response to uterine inoculation of 105 colony forming units (CFU) Escherichia coli in mares. Before inoculation, mares were classified as resistant or susceptible to persistent endometritis based on their uterine inflammatory response to infusion of 109 killed spermatozoa and histological assessment of the endometrial quality. Endometrial biopsies were obtained 3, 12, 24 and 72 hours (h) after bacterial inoculation and blood samples were obtained during the 7 day period post bacterial inoculation. Expression levels of cytokines and SAA were determined by quantitative real-time reverse transcriptase PCR (qRT-PCR).

Results: Compared to levels in a control biopsy (obtained in the subsequent estrous), resistant mares showed an up-regulation of IL-1β, IL-6, IL-8 and TNF-α at 3 h after E. coli inoculation, while susceptible mares showed increased gene expression of IL-6 and IL-1ra. Susceptible mares had a significant lower gene expression of TNF-α,IL-6 and increased expression of IL-1ra 3 h after E. coli inoculation compared to resistant mares. Susceptible mares showed a sustained and prolonged inflammatory response with increased gene expression levels of IL-1β, IL-8, IL-1ra and IL-1β:IL-1ra ratio throughout the entire study period (72 h), whereas levels in resistant mares returned to estrous control levels by 12 hours. Endometrial mRNA transcripts of IL-1β and IL-1ra were significantly higher in mares with heavy uterine bacterial growth compared to mares with no/mild growth.All blood parameters were unaffected by intrauterine E. coli infusion, except for a lower gene expression of IL-10 at 168 h and an increased expression of IL-1ra at 48 h observed in susceptible mares compared to resistant mares.

Conclusions: The current investigation suggests that endometrial mRNA transcripts of pro-inflammatory cytokines in response to endometritis are finely regulated in resistant mares, with initial high expression levels followed by normalization within a short period of time. Susceptible mares had a prolonged expression of pro-inflammatory cytokines, supporting the hypothesis that an unbalanced endometrial gene expression of inflammatory cytokines might play an important role in the pathogenesis of persistent endometritis.

Show MeSH
Related in: MedlinePlus