Effects Of Early Pregnancy On The Expression Of Reproductive Hormone Receptors In Ovine Lymph Nodes And The Thymus

Early pregnancy causes changes in ewe’ physiology and immune function that are related to reproductive hormones.Lymph nodes and thymus are important immune organs,but it is not clear whether early pregnancy affects the expression of reproductive hormone receptors in maternal lymph nodes and thymus.Reproductive hormone receptors include Follicle stimulating hormone receptor(FSHR),Luteinizing hormone receptor(LHR),Estrogen receptor(ESR),Adrenergic receptor(AR),Thyroxine receptor(THR),Insulin receptor(INSR)and Growth hormone receptor(GHR).In this experiment,18-month-old Small-Tailed Han sheep were selected as experimental animals.24 ewes were randomly divided into 4 groups(n = 6 in each group).Thymus and inguinal lymph nodes were collected on the 13 th,16th and 25 th day of pregnancy and the 16 th day of non-pregnancy after slaughter.Two immune organs were analyzed by real-time fluorescence quantitative PCR,Western blot and immunohistochemistry.1.Expression of reproductive hormone receptors AR,ESR,FSHR,GHR,INSR,LHR and THR in maternal lymph nodes of early pregnancy in sheep.The results showed that on the 16 th and 25 th day of pregnancy,the expression of m RNA and protein of FSHR and LHR were significantly different from those on the 16 th day and 13 th day of pregnancy(P<0.05).The expression of FSHR was down-regulated,while the expression of LHR was up-regulated.The relative expression levels of GHR and AR were the highest on the 16 th day of pregnancy.The expressions of ESR and INSR on the 13 th and 16 th day of pregnancy were higher than those on the 16 th day of non-pregnancy and the 25 th day of pregnancy(P<0.05).The relative expression level of THR was the highest on the13 th day of pregnancy.In addition,the immunohistochemical results showed that GHR and LHR proteins were mainly located in the subcapsular lymphatic sinus and lymphatic sinus in the cortex,indicating that reproductive hormone receptors in early pregnancy in sheep were related to the immune regulation of lymph nodes.2.Expression of reproductive hormone receptors AR,ER,FSHR,GHR,INSR,LHR and THR in thymus of early pregnant sheep.The results showed that the expression of m RNA and protein in FSHR on the 16 th and 25 th day of pregnancy were significantly lower than those on the 16 th day and the 13 th day of pregnancy(P<0.05).The expression of ESR on the 13 th and 16 th day of pregnancy was higher than that on the 16 th day of non-pregnancy and the 25 th day of pregnancy(P<0.05).The relative expression levels of INSR,LHR and THR were the highest on the 13 th day of pregnancy.The expression of GHR showed an upward trend during pregnancy.The expression level of AR on the 13 th and 25 th day of pregnancy was lower than that on the 16 th day of non-pregnancy and the16 th day of pregnancy(P<0.05).In addition,immunohistochemical staining showed that LHR and GHR proteins were expressed in thymic corpuscles and epithelial reticular cells,indicating that the receptor is related to the formation of thymic immune tolerance.In summary,early pregnancy leads to different changes in the expression of reproductive hormone receptors in maternal lymph nodes and the thymus,which may be related to maternal immune regulation and the occurrence of sheep pregnancy.