Early Pregnancy Influences the Expression of Estrogen Receptors in the Ovine Thymus, Lymph Node, Spleen, and Liver

Estrogen exerts its action via estrogen receptors (ERs), including ERα and ERβ, and has effects on immunomodulation during pregnancy. It is known that there is a remodeling in maternal immunology during pregnancy. However, it is not clear if early pregnancy has effects on the expression of ERα and ERβ in the maternal thymus, lymph nodes, spleen, and liver. In this study, these maternal immune organs were harvested at day 16 of the estrous cycle, and at days 13, 16, and 25 of pregnancy. The mRNA and protein expression of ERα and ERβ was analyzed. The results revealed that mRNA and protein expression of both ERα and ERβ was upregulated in the maternal spleen, and expression of ERα and ERβ in the thymus, lymph nodes, and liver was modulated during early pregnancy. In conclusion, early pregnancy modulates the expression of ERα and ERβ in the maternal thymus, lymph nodes, spleen, and liver in a tissue-specific manner, which is related to the regulation of maternal immune function during early pregnancy.