The endometrium regulates the inflammatory response after
infection by production and release of
cytokines and
chemokines. The objective was to compare gene expression of important pro-inflammatory (TNFα, IL-1β, IL-6) and anti-inflammatory (IL-10)
cytokines, and the main neutrophil
chemokine (IL-8), from calving to Week 7 after calving, in cows that developed
endometritis and healthy control cows. Uterine biopsies were obtained at calving and at Weeks 1, 3, 5 and 7.
Endometritis was evaluated at Week 5 by uterine lavage and cytology; cows with ≥ 10% neutrophils were considered to have
endometritis. Real-time RT-PCR threshold values (Ct) were used to calculate the fold difference in gene expression, using the 2(-ddCt) method, normalized to GAPDH and calibrated to the average dCt for all cows at calving. Serum
IL-8 concentrations were measured with ELISA. The analysis included 28 cows (11 had
endometritis) for the PCR data and 44 cows (20 had
endometritis) for ELISA. Expression of the TNFα gene in uterine tissue was decreased in cows with
endometritis compared to control cows at calving (P = 0.09) and at Week 1 (P = 0.05). Iterleukin-1β gene expression tended to be decreased (P = 0.08) in cows with
endometritis compared to control cows at Week 1, but tended to be increased (P ≤ 0.10) at Weeks 5 and 7. Cows with
endometritis had increased (P < 0.05)
IL-6 gene expression at calving and at Week 7 compared to control cows.
Interleukin-8 gene expression was increased (P = 0.03) in endometritic cows compared to control cows at Week 7.
Uterine disease was not significantly associated with
IL-10 gene expression. A lower local level of expression of pro-inflammatory
cytokines in the endometrium soon after calving might impair activation of
inflammation and clearance of bacteria, and lead to development of
endometritis.