Seminal plasma alters the endometrium during early embryo development in cattle

Seminal plasma is commonly known to serve as a survival medium to transport sperm cells through the male and then female reproductive tract. In rodents, swine and humans, seminal plasma actively modulates the cellular and molecular maternal environment at the time of conception and early embryo development. Artificial insemination in cattle minimizes female exposure to seminal plasma and deposits semen directly into the uterus, bypassing the vagina as the natural site of insemination. Seminal plasma exposure at insemination increases heifer birth weight, but the mechanisms are unknown. We hypothesized that supplementation of seminal plasma at insemination would alter the endometrial transcriptome and program early embryo development. As such, cows were subjected to estrus synchronization and superovulation followed by timed artificial insemination using X-sorted semen. Immediately following insemination, cows received an intrauterine infusion of either saline (n = 12) or seminal plasma (n = 14). On day 7 after insemination, embryos were non-surgically recovered and the endometrium was sampled for RNA sequencing. The number, morphology and quality of recovered embryos were not affected by seminal plasma infusion. A total of 107 differentially expressed genes (FDR ≤ 0.1) were identified in the endometrium that were related to 1) cellular immune responses, 2) cellular growth, proliferation, and development, and 3) cell morphology and embryonic development. We conclude that seminal plasma exposure at insemination alters the endometrial environment seven days after insemination and does not adversely impact embryo development.