Endometrial expression of selected transcripts in postpartum of primiparous Holstein cows with clinical and subclinical endometritis

Abstract

Postpartum endometritis compromises milk production and fertility in high-producing dairy cows. Infection of the endometrium induces an inflammatory response with secretion of cytokines that lead to polymorphonuclear cells (PMN) influx and bacterial clearance. Considering that only a portion of cows with endometritis is eligible for clinical diagnosis, there is an increasing effort for developing reliable tools and protocols for diagnosis of subclinical endometritis. Recent reports have indicated that primiparous cows are at greater risk of uterine infection and primiparous cows with subclinical endometritis produce less milk compared to healthy cows. In the present study, gene expression profiles were compared for selected cytokine and hormone endometrial transcripts in the postpartum of primiparous Holstein cows with clinical and subclinical endometritis. Cows were classified as healthy (no signs of clinical endometritis), cows with subclinical endometritis (PMN<5% in the cytological sample) and cows with clinical endometritis (PMN>5%). Although, cows with clinical endometritis had greater (P<0.05) relative amounts of mRNA for the IL1A, IL6, IL17A, TNFα, PGES and PGHS2 genes compared to healthy cows; no significant differences were detected between clinical and subclinical endometritis groups. Spearman correlation coefficients were positive between relative amounts of gene expression as indicated by amount of these transcripts and PMN percentages and ranged from 0.74 to 0.93 (P<0.05). Relative amounts of cytokine mRNA suggest similar inflammatory response in the endometrium of cows with subclinical and clinical endometritis. Moreover, differential relative amounts of hormone transcripts suggest dysregulation of the luteolytic mechanism and PG synthases but not ERα in cows with endometritis.