Effects Of Early Pregnancy On Toll-like Receptor Pathway And Complement Pathway In Ovine Thymus

Thymus is the key of mammalian immune system.Toll like receptors(TLRs)signaling pathway and complement signaling pathway are crucial to innate immune system.Complement activation is related to abnormal pregnancy in mice and human.This study speculated that TLR signaling pathway and complement signaling pathway are involved in the regulation of immune tolerance in the thymus of early pregnant sheep.This study includes:1.The expression of TLRs,TRAF6,IRAK1 and MyD88 in the thymus of sheep during early pregnancy.The thymus of sheep was collected on the 16 th day of estrus cycle,the 13 th,16th and 25 th day of pregnancy respectively.The expression of Toll like receptors was detected by real-time quantitative PCR,Western blot and immunohistochemistry2.Expression of complement components C1 q,C1r,C1 s,C2,C3,C4?,C5? and C9 in the thymus of early pregnant sheep.On the 16 th day of estrus cycle,the 13 th,16th and 25 th day after pregnancy,the expression of these factors in the thymus of sheep was detected by real-time fluorescence quantitative PCR,Western blot and immunohistochemistry.The results show that:1.The mRNA and protein expression of TLR2,IRAK1,TRAF6 and MyD88 decreased,while the expression of TLR5 increased.In addition,the expression of TLR3 and TLR4 peaked on the 13 th and 16 th day of pregnancy,and MyD88 protein was expressed in epithelial reticular cells and thymus corpuscles.It is suggested that TLR signaling pathway is involved in the immune regulation of the maternal thymus in early pregnancy of sheep,which may be realized by the down regulation of TLR2,IRAK1,TRAF6 and MyD88.2.During the early pregnancy,the mRNA and protein expression of C1 r,C1s,C2,C3 and C4? decreased,and the expression of C1 q,C5? and C9 peaked on the16 th day of pregnancy.In addition,C3 protein was expressed in epithelial cells and thymocytes.It is suggested that early pregnancy may result in the down regulation of maternal thymic complement pathway,which may be the necessary condition for successful pregnancy in sheep.Therefore,the TLR signaling pathway and complement signaling pathway in the maternal thymus are down regulated in early pregnancy,which is involved in the regulation of immune tolerance in the maternal thymus of sheep.