Upregulation of TLR-4 and proinflammatory cytokine transcripts as diagnostic indicator of endometritis in buffaloes

Abstract

The aim of present study was to examine the relative mRNA transcription of toll-like receptor 4 (TLR-4), CD14, interleukin-1β (IL-1β), interleukin-8 (IL-8), and tumor necrosis factor alpha (TNF-α) in endometritic buffaloes. Reproductive tracts were collected from 60 buffaloes at postmortem. The genitalia were diagnosed for endometritis based on positive white side test of uterine fluid, presence of >5% polymorphonuclear cells in uterine cytology, and endometrial histopathology. The endometritis-positive genitalia were categorized as luteal (n = 10) and follicular (n = 10) based on the presence of corpus luteum. Further, 20 normal genitalia (luteal, n = 10 and follicular, n = 10) were also included as control. The endometrial tissue scrapings were collected ex vivo from all the samples, total RNA was extracted, complementary DNA was transcribed for each sample, and relative quantification of mRNA was done by real-time polymerase chain reaction. The threshold cycle values of all the samples were normalized with the housekeeping β-actin gene and relative fold change was calculated using 2−ΔΔCt method. Present study revealed a variable upregulation of TLR-4, CD14, IL-1β, IL-8, and TNF-α transcription in endometritic buffaloes either at luteal or follicular stage. Predominantly at luteal stage, the significant upregulation of TLR-4, IL-8, and TNF-α transcripts was 4.66-, 21.19-, and 42.49-fold, respectively, indicated the possibility of cytokine-based diagnostic method for the early indication of endometritis before the onset of cyclic estrus. Nevertheless, further research in respect to threshold level of each cytokine in uterine biopsies involving more number of animals is required to establish a potential marker gene(s) for the diagnosis of endometritis and for devising novel therapeutic intervention.