Abstract #W27

# W27
Effect of repeated intravenous LPS infusions in endometrium gene expression and inflammatory response in Holstein heifers.
Artur C. C. Fernandes*1,2, Juliana S. Souza1, Douglas Veira1, Audrey Nadalin1, Lúcio E. H. Melo2, Ronaldo L. A. Cerri1, 1Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, Canada, 2Federal Rural University of Pernambuco, Recife, Pernambuco, Brazil.

This study aimed to evaluate the effect of repeated intravenous lipopolysaccharide (LPS) stimulus in endometrial gene expression of candidate transcripts of nonlactating heifers on late luteal phase. Heifers (n = 22; 11 mo of age) were synchronized by the ovsynch protocol and enrolled into control group (CON; n = 11) that received sterile saline solution i.v., or LPS group (LPS; n = 11) submitted to repeated LPS injections i.v. (0.1; 0.25; 0.5; 0.75; 1.0; 1.25 µg/kg WB) starting 2 d (d) after AI (d0), then every other d. At each injection, rectal temperatures were measured during 6 h. Blood samples were collected from the d-1 to d13, for analyses of TNF-α, haptoglobin, progesterone, and WBC count and differential. On d15, endometrium tissue biopsies were taken and kept at −80°C until qRT-PCR analysis of 30 target genes related to immune system, adhesion molecules and endometrium receptivity. Data were checked for normality and analyzed by ANOVA for repeated measures using proc MIXED and UNIVARIATE. After each injection, temperature was greater in the first 6h in the LPS compared with CON group (P < 0.05). Both TNF-α (P = 0.05) and haptoglobin (P < 0.01) were increased in the LPS group with significant (P < 0.05) treatment by d interactions. Total leukocyte count was not different between treatments (P = 0.29), but differential count was increased for neutrophils, band cells and monocytes, but decreased for lymphocytes and eosinophil in LPS compared with CON group (P < 0.01). Progesterone concentrations during the experimental period were not different between treatments. Out of the 30 target genes analyzed, only 3 transcripts were differentially expressed. IDO (P = 0.04; Fold = 0.48) and PTX3 (P = 0.01; Fold = 0.38) were downregulated, whereas MX1 (P = 0.02; Fold = 2.85) was upregulated in the LPS group. Sequential LPS injections was able to induce a systemic pro-inflammatory state with limited, but strong effect in gene expression of transcripts related to the immune system, suggesting a possible explanation for sub-fertility related to health disorders in dairy cows.

Key Words: gene expression, heifer, LPS