An approach to study the local embryo effect on gene expression in the bovine oviduct epithelium in vivo

Abstract

This study aimed to examine the local embryo effect on the transcriptomic response of the epithelial cells of the oviduct in vivo. Fifteen heifers were synchronized and artificially inseminated to a standing heat. All heifers were slaughtered on Day 2.5 after oestrus. The oviducts from 13 animals were isolated, trimmed free of tissue and divided between ampulla/isthmus. The ipsilateral isthmus was divided into smaller sections (2 cm). Each section was sequentially flushed until the embryo was located (4/13) and then opened and scraped longitudinally to obtain the epithelial cells. Cells were snap‐frozen in LN2 for gene expression analysis. All recovered embryos were found at the beginning of the isthmus. The 2 cm sections selected for the transcriptomic analysis were as follows: embryo section (in which the embryo was found); proximal section (through which the embryo had passed); distal section (on the uterine side of the embryo); and contralateral section (section from the contralateral isthmus). The expression pattern of eight genes (STK32A, KERA, QRFPR, MCTP1, PRELP, VAT1L, SOCS3 and CCL20) differentially expressed between the isthmus of pregnant (multiple embryo model) and cyclic heifers were assessed by RT‐qPCR. One‐way ANOVA and t test was used for statistical analysis. Comparisons between ipsilateral and contralateral oviduct or along the ipsilateral oviduct resulted in no differences for all genes. Despite the failure to detect a site‐specific response of a single embryo on the abundance of distinct transcripts in the bovine oviduct in vivo on Day 2.5, the current methodology with proposed modifications would be useful for future studies to examine the local embryo effect.

Analysis of the transcriptome of bovine endometrial cells isolated by laser micro-dissection (1): specific signatures of stromal, glandular and luminal epithelial cells

“…We identify here also original genes related to stromal cell differentiation and cell migration such as CDH11, PRELP, THY1 (the latter encoding a stem cell marker) [ 66 ], GJA1 [ 67 ], OSR2 [ 68 ], P4HA3. PRLEP gene expression has been reported to be regulated by the embryo in the bovine oviduct [ 69 ]. Contrary to the porcine endometrium where its expression was reported to be located in epithelial cells [[ 70 ], NTRK2 was mainly expressed here in stromal cells.…”

Composing the Early Embryonic Microenvironment: Physiology and Regulation of Oviductal Secretions

“…In accordance, the endoscopic transfer of 50 in vitro produced bovine zygotes on day 1.5 post-estrus in heifers led to significant changes in the gene expression of the isthmus on day 3 post-estrus [82]. In order to avoid a dilution of an embryonic effect in a physiological situation, Rodriguez-Alonso et al [83] focused on 2 cm oviduct sections in which the cattle embryo was retrieved on day 2.5 after insemination and made comparisons on candidate gene expression with adjacent sections in the same oviduct or with the same section in the contralateral oviduct. However, no site-specific effect of the cattle embryo could be evidenced with this method.…”

Changes in Oviductal Cells and Small Extracellular Vesicles miRNAs in Pregnant Cows

“…Different studies have demonstrated changes in gene expression patterns of bovine OECs co-cultured with embryos (11,12). In vivo, despite no differences in OECs gene expression were found using microarray analysis in the presence of a single embryo in artificially inseminated heifers compared to cyclic heifers by Maillo et al (13) or using target genes analysis by Rodríguez-Alonso et al (14), the same group identified differentially expressed genes by RNA-seq when multiples embryos were transferred (13). In the oviductal fluid, different proteins were described indicating that the fluid composition could be influenced by the presence of gametes (15).…”