Nuclear factor kappa B subunits and IkappaB family are modulated in the ovine endometrium during early pregnancy

Pregnancy modulates the endometrial immune responses to establish maternal immune tolerance, and nuclear factor kappa B (NF-κB) subunits and IκB family are involved in the maternal innate and adaptive immune responses. It, nevertheless, is unclear if early pregnancy regulates the expression of NF-κB subunits and inhibitor of NF-κB (IκB) family in the ovine endometrium. In this study, ovine endometria were sampled at day 16 of the estrous cycle (N16), and at days 13, 16, and 25 of pregnancy (P13, P16, and P25), and mRNA and protein expression of NF-κB subunits and IκB family was analyzed by RT-qPCR, western blot, and immunohistochemistry. The results revealed that the expression of all NF-κB subunits was decreased at P25 compared with N16 both in mRNA and protein expression, but the expression of B cell leukemia-3, IκBα, IκB kinase γ, and IκBδ was increased at P25 compared with N16 both in mRNA and protein expression. IκBβ, however, was down regulated during early pregnancy, and the expression of IκBε and IκBδ was decreased at P13 and P16 compared with N16 and P25 both in mRNA and protein expression. In summary, early pregnancy changed the expression of NF-κB subunits and IκB family in the ovine endometrium both in mRNA and protein expression, which may be essential for maternal immune tolerance and embryo implantation.