Embryo-Uterine Cross-Talk: Exploration of the Immunomodulatory Mechanism in Buffalo.

Understanding the molecular cross-talk between the embryo and uterine endometrium is crucial for the improvement of IVF outcomes. The present work was undertaken to investigate the effect of pre-implantation embryo on the expression profile of immune-related genes in uterine epithelial cells (UECs) and PBMCs in buffalo. UECs were isolated from slaughterhouse-derived non-gravid uteri, cultured ex vivo and characterized, and buffalo embryos were produced in vitro from slaughterhouse-derived ovaries. Embryos co-cultured with steroid-treated UECs significantly stimulated ( p < 0.05) the relative mRNA abundance of PTGS2 , ISG15 , OAS1 , MX2 , IFNAR1 and IFNAR2 in UECs while they significantly suppressed the mRNA expression of NFkβIA , NFkβ2 , TNFα and IL1B , with no significant change in TGFβ1 and IL10 in the co-culture of embryos with UECs. In vitro treatment of PBMCs with conditioned media (CM) derived from embryos as well as UEC-embryo co-culture upregulated the mRNA abundance of ISG15 , TGFβ1 , PTGS2OAS1 , MX2 and STAT1 while it downregulated IL17 and TNFα expression. The expression of IFNAR1 and IFNAR2 was elevated in PBMCs cultured in embryo-derived CM, but there was no significant change in PBMCs cultured in UEC-embryo co-culture CM. Thus, it can be concluded that the developing embryo and its secretions modulate the expression of immune responses by inducing an anti-inflammatory action in uterine epithelial cells for acceptance of the semi-allogenic embryo in the uterus to sustain pregnancy in buffalo.