AbstractThe bovine uterus is susceptible to infection, and the elevated cortisol level due to stress are common in cows after delivery. The essential trace element selenium plays a pivotal role in the antioxidant and anti‐inflammatory defence system of body. This study investigated whether selenium supplementation protected endometrial cells from inflammation in the presence of high‐level cortisol. The primary bovine endometrial epithelial cells were subjected toEscherichia colilipopolysaccharide to establish cellular inflammation model. The gene expression of inflammatory mediators and proinflammatory cytokines was measured by quantitative PCR. The key proteins of NF‐κB and MAPK signalling pathways were detected by Western blot and immunofluorescence. The result showed that pre‐treatment of Na2SeO3(1, 2 and 4 μΜ) decreased the mRNA expression of proinflammatory genes, inhibited the activation of NF‐κB and suppressed the phosphorylation of extracellular signal‐regulated kinase, P38MAPK and c‐Jun N‐terminal kinase. This inhibition of inflammation was more apparent in the presence of high‐level cortisol (30 ng/mL). These results indicated that selenium has an anti‐inflammatory effect, which is mediated via NF‐κB and MAPK signalling pathways and is augmented by cortisol in bovine endometrial epithelial cells.