Expression of IK Cytokine in Mouse Uterus of Early Pregnancy and Its Significance in Embryo Implantation

Abstract: The expression of IK cytokine was investigated in mice endometria during early pregnancy (D1~D7 of pregnancy) and pseudopregnancy using Real-time PCR， Western blot and immunohistochemical analysis， and the effect of IK cytokine on embryo implantation was observed by uterus horns injection of antisense IK cytokine oligodexynucleotides. Our data showed that the expression of IK cytokine mRNA increased gradually from D1 to D4 of pregnancy and reached a peak level at D4 of pregnancy (P<0.05). Western blot and immunohistochemical analysis revealed that the expression of IK cytokine protein increased gradually from D1 to D5 of pregnancy and reached a peak level at D5 of pregnancy (P<0.05). The expression of IK cytokine in the pseudopregnant uterus was significantly lower than that in the normal pregnant uterus and the level of the protein never showed a high peak during the whole pseudopregnancy. The expression of IK cytokine at the implantation site was much stronger than that in the inter-implantation segment at D5 of pregnancy. After 24 h and 48 h of treatment with antisense oligodexynucleotides of IK cytokine， the expression of IK cytokine in the uterus was remarkably inhibited， while the expression of MHCII increased and the number of implanted embryos significantly reduced (P<0.05). These results suggested that IK cytokine played a crucial role in implantation. The suppression of MHCII antigens by IK cytokine was likely to inhibit the fetal-maternal immune responses， contributing to the maintenance of successful pregnancy.

CSTR: 32200.14.cjcb.2012.05.0002