GSE134518
Association between progesterone concentration in early diestrus and endometrial gene expression in grazing dairy cows
The objective of this study was to evaluate the association between progesterone concentration (P4) at day 4 of the estrous cycle (beginning of diestrus) and endometrial global gene expression at day 9 (middle diestrus) in lactating grazing dairy cows. Blood samples were obtained on days 0, 4 and 9 for P4 measurement by chemiluminescence. Cows were asignated to one of the following groups (n=3/group): cows with low physiological P4 at day 4 (PLP4), cows in anestrous (ANE), cows with high physiological P4 at day 4 (HPP4) and superovulated cows (SO). Endometrial biopsy samples were obtained on day 9 for RNA sequencing. Quality control and determination of differentially expressed genes (DEG; FDR<0.05) were determined using the edgeR package for R. The number of DEG between groups were: HPP4 vs LPP4: 453; HPP4 vs ANE: 623; SO vs LPP4: 603; SO vs ANE: 1102; LPP4 vs ANE: 261 and SO vs HPP4: 0. Functional analysis using the DAVID database revealed that endometrial genes upregulated by low P4 are enriched in the immune system and inflammatory response. Conversely, genes upregulated by high P4 are enriched inmodulation of uterine relaxation-contraction, GnRH signaling pathway, focal adhesion and EGF-like related terms. In conclusion, our results support the concept of changes in P4 at the beginning of the luteal phase could be associated with the endometrial expression of critical genes involved in the preparation of the uterine environment for embryo implantation. Overall design: 12 endometrial samples were analyzed, with 3 replicates per group (4 groups).