Expression of Pathogen Recognition Receptors and Pro-Inflammatory Cytokine Transcripts in Clinical and Sub-Clinical Endometritis Cows

Abstract

The present study was carried out to examine the expression profile of pathogen recognition receptors (CD14 and toll-like receptor 4) and pro-inflammatory cytokines (IL-1β, IL-6, IL-8, and TNFα) in endometrial tissue of cows with endometritis at different stages of estrous cycle. Genital tracts were collected from 60 cows at slaughter from the killing village. The genitalia were examined for clinical endometritis (CE) and subclinical endometritis (SCE) through physical examination, white side test of cervico-vaginal mucus, endometrial cytology and histopathology. The stage of estrous cycle for each genitalia was determined by visual examination of both the ovaries and classified as either follicular (F) or luteal (L). Depending on the degree of inflammation and stage of estrous cycle, the genitalia were categorized in four groups i.e., FCE, FSCE, LCE, and LSCE with six genitalia in each group. Furthermore, 12 healthy genitalia comprise of six each of follicular (FN) and luteal (LN) were included as control. Endometrial tissue scrapings were collected ex vivo from all the genitalia. Total RNA was extracted and cDNA was transcribed for each sample and relative quantification of mRNA of target genes was done by real-time PCR. The results revealed a significant up-regulation of CD14 (11 fold) and IL-8 (13 fold) in follicular stage and IL-6 (8 fold) and TNFα (29 fold) in luteal stages in SCE cows. However, the majority of pro-inflammatory cytokine and pathogen recognition receptors expressed at significant higher level in both follicular and luteal stages in cows with CE. Thus, it is concluded that the endometrial transcripts of pathogen recognition receptors and pro-inflammatory cytokines expressed differentially in cows with endometritis, whereas the fold change is dependent on the severity of inflammation and the stage of cyclicity. Therefore, endometrial transcript profile with a defined threshold level could be used as a possible diagnostic marker in cows with SCE.