Immunohistochemical Localization Of P450 Aromatase On Gonads In Fetal Pig

Mammalian gonads experience a series of important developmental changes at fetal stage. Such events include primordial germ cell generation and migeration, gonadal cord and gonad formation, germ cell proliferating, differentiation and apoptosis. Studies on these activities will help understand the reproductive development process, like sex differentiation, gametogenesis and so on. Pig production plays an important role in husbandry in our country animal. Moreover, such species has special significance in human medicine, especially in xenotransplantation since the size, form and structure of its organ are more similar to human than others. Recognition of porcine gametogenesis was of the great importance in livestock reproduction and human reproductive clinics.This experiment investigated the immunohistochemical localisation of P450arom on the fetal porcine gonads at 33, 40, 46, 54, and 61 days old respectively. The results showed that the P450arom was immunoactive in the cytoplasm and nucleus of oogonium and in the cytoplasm of surface epithelium on 33 d fetal ovaries; the P450arom was immunopositive in the synplasma-like oogonia and the cytoplasm of surface epithelium on 40 d fetal ovaries, the same on 47 d fetal ovaries; the P450arom was weakly localized in the cytoplasm of oocyte in the cortex of ovarise at 54 d fetal ovaries; The P450arom positive staining was weak in the medulla of ovarise but strong in the cytoplasm of oocytes on 61 d fetal ovaries.In male fetal testis, the P450arom was expressed in the cytoplasm of tunica testis and in the cytoplasm and nucleus of spermatogonium on 33 d fetal testes; The P450arom immunoreactivity was quite weak in the seminiferous tubule and tunica testes, but strong in Leydig cells on 40 d fetal testes; The P450arom immunoreactivity was much stronger in the germ cells than in the Leydig cells, and also in the cytoplasm of tunica testis on 47 d fetal testes; The P450arom immunoreactivity was stronger in the Leydig cells than in the germ cells on 54 d fetal testes; The P450arom was immunoreactive in the germ cells in the seminiferous tubule, but not in the Leydig cel, the same in the cytoplasm of surface epithelium of testes. This is the first time to reveal that P450arom existence on 33 d fetal pig ovaries. Taking all of the findings into consideration, we presume that P450arom play a role in porcine fetal ovary and testis development during gametogenesis.