Ejaculate fraction-driven changes in porcine uterine gene expression and histological profiles

Area of Science:

• Reproductive Biology
• Animal Science
• Genomics

Background:

• Seminal plasma (SP) contains bioactive components that modulate the female reproductive tract.
• Boar ejaculate fractionation yields portions with distinct compositions.
• The cumulative impact of these fractions on the uterine environment is not well understood.

Purpose of the Study:

• To investigate how stepwise inclusion of boar ejaculate fractions affects uterine gene expression, cell proliferation, and immune response in sows post-artificial insemination (AI).

Main Methods:

• Sows were artificially inseminated with semen doses comprising different ejaculate fraction combinations (FR1, FR2, FR3) or left as a control.
• Uterine tissues were collected 6 days post-estrus for transcriptomic (RNA-sequencing) and histological analyses.
• Gene expression, cell proliferation (Ki-67), and immune cell infiltration (CD3+ T-cells) were quantified.

Main Results:

• RNA-sequencing revealed the highest number of differentially expressed genes (DEGs) in the FR2 group, followed by FR3 and FR1, compared to controls.
• Most DEGs were downregulated, including immune-related genes like VNN2.
• Histology showed reduced cell proliferation and T-cell infiltration in all AI groups, with enhanced transition to a secretory phenotype in FR2 and FR3 groups.

Conclusions:

• The stepwise inclusion of boar ejaculate fractions elicits distinct uterine transcriptomic and histological responses.
• Seminal plasma composition significantly influences the uterine environment.
• Fraction-specific SP components may play a crucial role in modulating early pregnancy outcomes in sows.