Expression And Regulation Of Basigin Gene In Rat Uterus,ovary And Preimplantation Embryo

Basigin. a highly glycosylated transmembrane protein belonging to the immunoglobulin superfamily, is shown to be important for mouse implantation and spermatogenesis. The aim of this project was to study basigin expression in rat uterus during early pregnancy and estrus cycle, and its regulation under pseudopregnancy, delayed implantation, artificial decidualization and steroid treatment by in situ hybridization and immunohistochemistry. The expression of basigin gene in preimplantation embryo was also determined by RT-PCR. Basigin expression in the ovary of immatural rat and gonadotrophin-treated immatural rat was also examined by in situ hybridization and immunohistochemistry to establish its role in folliculogenesis and formation and regression of corpus luteum.1.Basigin mRNA was detected in the luminal epithelium on days I to 9 and in the glandular epithelium on days 3 to 6 of pregnancy. Basigin protein was detected in the Iuminal epithelium on days I to 3 and in the glandular epithelium on days 2 to 5 of pregnancy. Basigin was strongly expressed in embryo proper and decidua on days 6 to 9 of pregnancy.2.Basigin mRNA was detected in oocytes and all the stages of preimplantation embryos. The expression increased gradually from zygote to blastocyst stage.3.There was a low level of basigin mRNA expression in the luminal epithelium on days 1 to 8 of pseudopregnancy and glandular epithelium on days 2 to 6 of pseudopregnancy. Basigin protein was detected in the luminal epithelium on days I to 2 of pseudopregnancy and in the glandular epithelium on days 2 to 5 of pseudopregnancy.4.Basigin expression in the embryos and sub-luminal stroma surrounding embryo was intensively induced when delayed implantation was terminated by estrogen treatment, while there is no distinct signal in the uterus under delaying implantation.5.Basigin was highly expressed in the whole deciduas under artificial decidualization, while basigin was only weakly expressed in the luminal epithelium of control uterus horn.6.A moderate level of basigin expression was detected in the luminal epithelium during estrous cycle. The level at proestrus, estrus and metestrus was higher than that at diestrus.7.Basigin expression in the uterus of ovariectomized mice was significantly stimulated by estrogen or a combination of estrogen and progesterone.8.Basigin mRNA was highly expressed in granular cells of different development phases and well-developmented theca cells, while basigin protein was highly expressed in developing theca cells.9.Basigin expression was low in the forming corpus luteum following ovulation, and increased gradually thereafter. Basigin mRNA and protein reached to peak on day 5 and day 7 after hCG injection, respectively.In conclusion, these results suggest that basigin expression is closely related to embryo implantation and decidualization, and may play an important role during the folliculogenesis and the formation of corpus leuleum.