Differential gene expression profiling of endometrium during the mid-luteal phase of the estrous cycle between repeat breeder and normal fertile cows

We investigated differential gene expression profiles of endometrium during the mid-luteal phase of the estrous cycle between repeat breeding (RB) and normally fertilized cows using microarray analysis. Caruncular (CAR) and intercaruncular (ICAR) endometrium of both ipsilateral and contralateral uterine horns to the corpus luteum were collected from RB (inseminated at least three times but not pregnant) and normally fertile cows on Day 15 of the estrous cycle. Global gene expression profiles of these endometrial samples were analyzed with a 15K custom-made oligo-microarray in cattle. Microarray analysis revealed that 405 and 397 genes were differentially expressed in CAR and ICAR of the ipsilateral uterine horn of RB, respectively when compared with normal cows. In contralateral uterine horn, 443 and 257 differentially expressed genes were identified in the CAR and ICAR of RB, respectively when compared with normal cows. In the analysis of whole uterine (combining the above four portions), RB cows showed up-regulation of 37 genes including PRSS2, GSTA3, PIPOX, CNGA1 and IGG1C and down-regulation of 39 genes including CHGA, KRT35, THBS4, CPXM2 and PRF1 compared with normal cows. Our results may suggest that local regulation of molecular mechanisms in each uterine portion contributes to normal uterine physiology. This study was carried out using non-lactating Japanease Black cows in the institute ranch. Repeat breeding (n=4) and normally fertile cows (n=4) were slaughtered on Day 15 of the estrous cycle (the day of estrus was designated as Day 0), and collected endometrial tissues. We collected caruncular and intercaruncular areas in endometrium of both ipsilateral and contralateral uterine horns to the ovary containing the corpus luteum (CL).