Gene profiling of inflammatory genes in day 18 endometria from pregnant and non-pregnant mares

Maternal recognition of pregnancy is a physiological process that primarily describes endometrial responses to a conceptus. Recognition of a conceptus prevents the release of prostaglandin F2α, thereby ensuring survival of the corpus luteum and continued progesterone production. Exactly how this occurs in the mare is poorly understood. Because prostaglandin F2α is a pro-inflammatory hormone, we hypothesized that differential gene expression in the endometrium at the time of maternal recognition reflects an anti-inflammatory event leading to decreased prostaglandin F2α secretion. Mares were inseminated, and endometrial biopsies were recovered from pregnant mares on Day 18 post-ovulation. In subsequent estrous cycles, mares were not inseminated and Day 18 post-ovulation endometrial biopsies were collected (non-pregnant control, matched per individual). Endometrial gene expression profiles were examined by screening an Affymetrix equine GeneChip containing probes specific for genes related to inflammatory processes. Microarray analysis revealed 118 genes that were up-regulated and 93 genes that were down-regulated (P