| The success of pregnancy is closely related to the mechanism of maternal immunosuppression.The loss and abortion of sheep embryos have seriously affected the economic efficiency of sheep farms,and the exact mechanism of maternal immunosuppression in early pregnancy remains unclear.Nod-like receptors(nucleotide oligomerization domain(NOD)-like receptor,NLR)are a class of pattern recognition receptors of innate immunity,which play a unique role in innate immunity,inflammatory response and early embrygenesis in mammals.IκB(inhibitor of nuclear factor kappa-B)and IκB kinase(IKK)play an important role in immune response,inflammation and apoptosis.The spleen is an important base of immune response.The effects of early pregnancy on Nod-like receptor pathway and IKK pathway in sheep spleen were studied to provide evidence for the immune mechanism of sheep during pregnancy.The 18-month-old small-tailed Han sheep was selected as the experimental animal.24 ewes were randomly divided into 4 groups(6 ewes in each group).After estrus treatment,the sheep were slaughtered and the spleen was collected on the 13 th,16th and 25 th day of pregnancy and the 16 th day of the estrous cycle,respectively.Real-time fluorescence quantitative PCR,Western blot and immunohistochemistry were used to analyze the expression of genes and proteins in the two signaling pathways.1.Expression of NOD1,NOD2,CIITA(Major histocompatibility complex class II transactivator),NAIP(Neuronal apoptosis inhibitory protein),NLRP1,NLRP3 and NLRP7 in the NOD-like receptor pathway in the spleen of sheep during early pregnancy.The results showed that the expression levels of NOD1,NOD2,CIITA and NLRP3 on the days 13 and 16 day of pregnancy were lower than that at day 16 of the estrous cycle and day 25 of pregnancy(P<0.05).The expression of NAIP and NLRP7 on the days 16 and 25 of pregnancy was significantly higher than that on the day 16 of the estrous cycle and day 13 of pregnancy(P<0.05).However,compared with the day16 of non-pregnancy and the day 25 of pregnancy,the expression of NLRP1 increased on the days 13 and 16 of pregnancy(P<0.05).Immunohistochemical results showed that NOD2 and NLRP7 proteins were localized in the capsule,trabeculae and splenic cord.2.Expression of BCL-3(B-celllymphomafactor 3),IκBα,IκBβ,IκBε,IKKγ,NFKBID and IκBζ in the spleen IKK pathway of sheep during early pregnancy.The results showed that the expression levels of BCL-3,IκBα,IκBε and IKKγ were significantly up-regulated in the early pregnancy compared with those on the day 16 of non-pregnancy(P<0.05).And the expression level of BCL-3 was the highest on the day 16 of pregnancy.Compared with the day 16 of non-pregnancy and the day 13 of pregnancy,the expression level of IκBζ was significantly increased on the days 16 and25 of pregnancy(P<0.05).In addition,compared with day 16 of non-pregnancy and day 25 of pregnancy,the expression levels of IκBβ and NFKBID were significantly up-regulated on day 16 of pregnancy,while the level of IκBβ was down-regulated on day 13 of pregnancy(P<0.05).Immunohistochemical results showed that IκBβ and IKKγ proteins were located in the capsule,trabeculae and splenic cord.In summary,early pregnancy can induce the up-regulation of maternal splenic immune function,which may be beneficial to the regulation of maternal splenic immune response in early pregnancy.These regulations contribute to the regulation of maternal immune tolerance in the early stage of pregnancy,which plays an important role in the implantation of embryos and the normal maintenance of pregnancy. |
