Inflammatory cytokines and acute-phase proteins concentrations in the peripheral blood and uterus of cows that developed endometritis during early postpartum

The aim of the study was to evaluate the level of proinflammatory cytokines (tumor necrosis factor-α [TNF-α], interleukin-6 [IL-6]), anti-inflammatory cytokine (interleukin-10 [IL-10]), and acute-phase proteins (haptoglobin [Hp] and serum amyloid A [SAA]) in serum and uterine washings in cows that developed endometritis during the early postpartum period. The study was carried out on 40 cows. The experimental group consisted of 20 cows with subclinical endometritis and the control group of 20 cows without endometritis. Analyses in both groups of cows were carried out at 5, 22, and 40 days postpartum (DPP). Experimental material consisted of the blood serum and uterine washings. The levels of the following cytokines: TNF-α, IL-6, IL-10 and acute-phase proteins: Hp and SAA were determined using ELISA. Our study reported that the levels of TNF-α, IL-6, IL-10, Hp, and SAA at 22 DPP were higher in cows with subclinical endometritis (P < 0.001). The levels of TNF-α (P = 0.01), IL-6 and IL-10 (P = 0.001), and Hp (P < 0.001) at 40 DPP were higher in cows with subclinical endometritis compared to healthy cows. The level of IL-10 in uterine washings at 5 DPP was higher (P = 0.001), whereas of SAA was lower (P = 0.01) in cows with subclinical endometritis. At 22 DPP, the levels of IL-6, IL-10, and Hp were higher (P < 0.001) in cows with endometritis. At 40 DPP, the level of TNF-α was lower, whereas these of IL-10 and Hp were elevated (P < 0.001) in cows with endometritis compared to healthy cows. The results indicate that the evaluation of the levels of cytokines and Hp in serum, but primarily in uterine washings, can be an important diagnostic indicator in cows that developed subclinical endometritis. High levels of IL-10 in cows with subclinical endometritis may contribute to the weakening of local resistance mechanisms of the uterus and lead to the persistence of the inflammation in the postpartum period. The present study also shows that the simultaneous examination of selected parameters of antagonistic interactions allows for better assessment of the current state of local immunity in the uterus.