The Expression Of IGF-Ⅰ In Hypothalamus-Pituitary-Gonadal Axis Of Early Pregnant Rats And Its Regulation By IFN-γ

In order to investigate the neuroimmune regulation of IGF-Ⅰin the process of early pregnancy and the interactions between IGF-Ⅰand IFN-γ, we took pregnant Spreque-Dawley rats as our model, immunohistochemical SP method was used to study the expression of IGF-Ⅰin the HPG axis and effect of the high dose of IFN-γon it during pre-implantation and post-implantation periods. And , at the same time, we compared the differences of IGF-Ⅰpositive substance locations between these two priods. The results were as follows:1. The immunopositive substance was widely distributed in the HPG axis during early pregnancy. In hypothalamus, the IGF-Ⅰwas mainly expressed in the preoptic area and suprachiasmatic area. Positive substance was existed in the nucleus pre-opticus periventricularis, nucleus supra-opticus, nucleus pre-opticus mango celluaris, nucleus pre-opticus medialis, nucleus pre-opticus lateralis, nucleus pre-opticus suprachiasmaticus,nucleus arcuatus hypothalami;In the pituitary, the immunopositive substance was located in the membrane and cytoplasm of adenohypophysis gland cells, as well as in the fibers of neurohypophysis; In the uterus, IGF-Ⅰwas expressed in the decidual cells, glandular and cavity epithelium; In the ovary, immunopositive substance was mainly existed in the corpus luteum, granular cells of mature follicle and follicular fluid. The expression of IGF-Ⅰin pituitary, uterus and ovary was weak positive during this stage. It was showed that IGF-Ⅰwas a kind of very important cytokines which regulated the function of HPG axis during pre-implantation period.2. IGF-Ⅰwas widely existed in the HPG axis during post-implantation period. The location of IGF-Ⅰimmunopositive substance during this stage was similar with the ones of pre-implantation period, while the only difference was the expression intensity was stronger than the earlier stage; The condition in the pituitary was also resemble with the earlier period; In the uterus, IGF-Ⅰwas appeared in matrix material cells of decidual, glandular epithelium; In the ovary, the location of IGF-Ⅰimmunopositive substance also had no difference with the last period. The expression intensity in all these sites was strongly positive. It was suggested that IGF-Ⅰhad important regulated functions to post-implantation pregnant rats through the way of feedback of HPG axis.3. By comparison of expression of IGF-Ⅰin the HPG axis of these two period, we found that the locations of IGF-Ⅰimmunopositive substance in the hypothalamus were similar, however, the expression intensity during post-implantation period was significantly stronger than the pre-implantation period, as well as in the pituitary. During the pre-implantation period, the positive substance was mainly located in the cytoplasm and nucleus of decidual cell, while in the uterine gland, the IGF-Ⅰwas expressed on the whole glandular epithelium. In the post-implantation period, IGF-Ⅰimmunopositive substance was existed in membrane and cytoplasm of decidual cells, the nucleus had no IGF-Ⅰexpression at all; in uterine gland, the positive substance was located on the membrane of glandular cells and peripheral stromal. There was difference of positive substance location in uterus between these two periods, however, the expression quality in pre-implantation was lower than the ones of post-implantation period, as well as in the ovary.4. When the pregnant rats was treated with 2.5×10~4 U and 7.5×10~4 U IFN-γ, the expression of IGF-Ⅰwas obviously decreased during both two periods. Hence, we conclude that the high dose of IFN-γcould inhibit the expression of IGF-1 in the HPG axis.According to what had been mentioned above, IGF-Ⅰcould effect the pregnancy through the way of HPG axis during pre- and post-implantation periods, while the high dose of IFN-γcould extenuate its function to pregnancy. So, we concluded that there were complex interactions between IFN-γand IGF-Ⅰi n the network of pregnant cytokines. Both of them two were indispensable in the process of normal pregnancy.