Impact of subclinical endometritis on circulating white blood cells and endometrium of dairy holstein cows at postpartum period

Cattle with subclinical endometritis (SCE) are sub-fertile, but there is no predictive or diagnosis tool for subclinical uterine disease. The hypothesis for this study was that endometrial inflammation is reflected in peripheral blood leucocytes gene expression. Transcriptome patterns in healthy cows and in cows with SCE at 45-55 days postpartum were evaluated using circulating white blood cells and endometrial biopsies samples collected from the same animals. Bioinformatics analyses of microarray-based transcriptional data identified gene profiles associated with distinct biological functions in circulating white blood cells and endometrium. In circulating white blood cells SCE promote a pro-inflammatory environment related to the activation of inflammation, whereas in the endometrium functions also related to tissue remodeling. Nineteen differentially expressed genes were altered both in circulating white blood cells and in the endometrium of SCE cows compared with healthy cows. Among these genes, transcript abundance of immune factors C3, C2, LTF, PF4 and TRAPPC13 were up-regulated in SCE cows at 45-55 days postpartum. Moreover, the mRNA expression of C3, CXCL8, LTF, TLR2 and TRAPPC13 was temporally regulated during the postpartum period in circulating white blood cells from healthy cows compared with SCE cows. This observation might indicate an advantageous activation of the immune system in healthy animals. The transcript abundance of these genes might also be used as an indicator for subsequent postpartum uterine health. Eight total RNA samples isolated from endometrial biopsy samples collected from subclinical (n =4) and healthy animals (n = 4) and 8 total RNA samples isolated from PAXgene blood samples from the same animals were hybridized.Transcriptional profiling was performed using a custom bovine array generated by merging oligonucleotides set of the Agilent bovine 44K microarray (Gene Expression Omnibus accession no 023647_B. Taurus Oligo Microarray V2_1 and V2_4) with a non-commercial bovine INRA 22K (13,257-element bovine oligonucleotides array, National Center for Biotechnology Information Gene Expression Omnibus accession no. GPL2853). A Custom bovine Gene Expression array 8x60K designed on bovine annotated Ensembl transcripts (http://www.ensembl.org/index.html, genome assembly UMD3.1) completed with 2100 Ensembl references representing 1632 NCB1 specific transcripts (https://www.ncbi.nlm.nih.gov/) found on the INRA 22K array. For each transcript gene (3 independent X 2) 60-mer oligonucleotides (probes) were designed using Agilent software, eArray (https://earray.chem.agilent.com/earray/). This custom bovine gene expression array containing 19,479 transcripts was manufactured by Agilent SurePrint Technology using In situ synthesis Printing Process. RNA labeling was performed according to Agilent protocol “One-Color Microarray-Based Gene Expression Analysis – Low Input Quick Amp Labelling” version 6.5, May 2010 (Cat # G4140-90050).