Increased mRNA expression of selected pro-inflammatory factors in inflamed bovine endometrium in vivo as well as in endometrial epithelial cells exposed to Bacillus pumilus in vitro

Abstract

Endometrial epithelium plays a crucial role in the first immune response to invading bacteria by producing cytokines and chemokines. The aim of this study was to investigate the first inflammatory response of the endometrium in vivo and in vitro. Gene expression of several pro-inflammatory factors and Toll-like receptors (TLR2, -4, -6) was determined in endometrial cytobrush samples obtained from healthy cows and cows with clinical or subclinical endometritis. Endometrial epithelial cells were co-cultured with an isolated autochthonous uterine bacterial strain Bacillus pumilus. Total RNA was extracted from in vivo and in vitro samples and subjected to real-time reverse transcription polymerase chain reaction. CXC ligands (CXCL) 1/2 and CXC chemokine receptor (CXCR) 2 mRNA expression was higher in cows with subclinical endometritis and CXCL3 mRNA expression was higher in cows with clinical endometritis compared with healthy cows. B. pumilus induced cell death of epithelial cells within 24h of co-culturing. The presence of B. pumilus resulted in significantly higher mRNA expression of interleukin 1α (IL1A), IL6, IL8, CXCL1-3 and prostaglandin-endoperoxide synthase 2 in co-cultured cells compared with untreated controls. The maximum increase was mainly detected after 2h. These results support the hypothesis that bacterial infection of endometrial cells might induce prompt synthesis of pro-inflammatory cytokines resulting in a local inflammatory reaction.

Influence of intrauterine administration of Lactobacillus buchneri on reproductive performance and pro-inflammatory endometrial mRNA expression of cows with subclinical endometritis

“…Three weeks after the intrauterine administration of L. buchneri DSM 32407 or the placebo, the mRNA of CXCL1 / 2, CXCL3 , CXCR2 , IL1B , IL8 and PTPRC was lower expressed in the LAC / SCE group compared with the PLA/SCE group. These pro-inflammatory factors were higher expressed in cows with signs of SCE and/or CE and thereby related to uterine health problems in a recent study at the same time point 24 and in previous studies at earlier time points of the puerperium 21 , 23 , 33 . The mRNA data of the present study thereby indicates that the endometrial immune system of cows treated with L. buchneri is downregulated three weeks after its administration to the uterus.…”

“…Primers named CXCL1/2 are specific for CXCL1 as well as for CXCL2 33 . At E4 , CXCL1/2 and CXCL3 mRNA was seven- and threefold more highly expressed in the PLA / SCE group compared with the LAC / SCE group, respectively (Fig.…”

“…In a former study was shown that the strain L. buchneri DSM 32407 did neither influence the viability of endometrial epithelial cells nor provoke a pro-inflammatory response in contrast to other Lactobacillus strains 16 . Pathogenic ( Trueperella pyogenes ) or potential pathogenic strains ( Bacillus pumilus ) caused cell death even within 16–24 h 33 , 34 . Therefore, the strain L. buchneri DSM 32407 seems suitable to serve as a probiotic strain within the bovine uterus to modulate the immune response and the reproductive performance of dairy cows.…”

Subclinical Endometritis in Dairy Cattle

“…Results of the cited studies suggest that common pathogens associated with metritis and clinical endometritis do not have a significant role in the SE pathogenesis. It has been suggested that SE may be a response to unspecific uterine infections [19] or a prolonged inflammatory process that persists after bacterial elimination.…”

Corynebacterium urogenitale sp. nov. isolated from the genital tract of a cow

“…In order to test if strain LMM-1652 T possesses any pathogenic potential, its cytotoxicity was tested in vitro using primary bovine endometrial epithelial cells, as described previously [33]. In brief, primary cells were prepared up to the second passage and were infected with strain LMM-1652 T in different multiplicities of infection (MOIs) and cell viability was assessed by using 0.5 % trypan blue (Sigma-Aldrich).…”