Profile of mRNA expression in the myometrium after intrauterine Escherichia coli injections in pigs.

Endometritis and metritis are common reproductive diseases in domestic animals, causing a reduction in reproductive performance and economic losses. A previous study revealed the alterations in the transcriptome of the inflamed porcine endometrium. Data on molecular signatures in the myometrium under inflammatory conditions are limited. The current study analyzed the transcriptomic profile of porcine myometrium after intrauterine Escherichia coli (E.coli) administration. On day 3 of the estrous cycle (Day 0 of the study), 50 ml of either saline (group CON, n = 7) or E. coli suspension (10 colony-forming units/ml, group E. coli, n = 5) were injected into each uterine horn. After eight days, the gilts were euthanized, and the uteri were removed for further analysis. In the myometrium of the CON group versus the E. coli group, microarray analysis revealed 167 differentially expressed genes (DEGs, 78 up- and 89 down-regulated). After intrauterine E. coli administration, among the DEGs of the inflammatory response set, the highest expressed were mRNA for CXCL6, S100A8, S100A12, SLC11A1, S100A9, CCL15, CCR1, CD163, THBS1 and SOCS3, while the most suppressed was mRNA expression for FFAR4, KL, SLC7A2 and MOAB. Furthermore, a comparison of the present results on myometrial transcriptome with the authors' earlier published data on the endometrial transcriptome shows the partial differences in mRNA expression between both layers after intrauterine E.coli injections. This study, for the first time, presents changes in the transcriptome of porcine myometrium after intrauterine E.coli administration, which may be important for myometrial homeostasis and functions and, as a result, for the uterine inflammation course. Data provide a valuable resource for further studies on genes and pathways regulating uterine inflammation and functions.