Early Germ Cell Distribution In The Quail Blastodisc And The Gonad Development Of Quail Embryo

In the paper, the PGCs'origin and migration of quail was studied, as well as the differentiation and development of gonad at microscopic levels. The results was as follows:1 The distribution and number of primordial germ cells has been analyzed in the quail blastodiscs from the incubated state to the 18-somite stage, treated in toto with monoclonal antibody QH1. At the unincubated blastodisc, most of PGCs were located in the area opaca, close to the aera opaca near its boundary with the area pellucida. They were usually isolated and sometimes associated by two. At blastulas incubated 12h stage, most of PGCs were located in the area pellucida. These cells were often gathered by three. At stage of the head process stage, most PGCs were located in the anterior half of the blastoderms although a few isolated groups were sometimes observed in a more caudal location. The cells in the anterior half were principally concentrated at the boundary between the area opaca and the area pellucida in the position classically designated as the germinal crescent. The number of PGCs increased from 2-3 in the unincubated state to more than 100 at the Primitive streak. And this is a proliferating peak stage. Between the first somite and seventh somite stages, however, PGCs enter the blood vascular system. At the seventh somite stage, there had been a few PGCs enter the blood vascular system. To the tenth somite stage, a lot of PGCs gathered in the blood vascular system of two bilateral. The numer is the most of detected stage. At the eighteen somite stage, PGCs surround in the heart,big blood vessels and head of chick embryo, mostly in the blood vessels of the head mesenchyme.2 To learn the time of the gonad differentiation for quail embryo, we performed H.E. staining and the results showed that: At the 4th hatching day, PGCs had translated to original gonad, along with which to form the undifferentiated gonad. At the 5th hatching day, the gonad had differentiated into ovaries and testis. During the differentiation of ovary, there was a layer of cells as the appearance of PGCs under the gonad epithelial, which seperated from the under layer into two parts. That was the dense cortical layer and the loose medullary layer. During the differentiation of testis, early albuginea by the formation of mesenchymal cells was under the epithelial, which seperated the inner cells from the epithelial. The cell mass in the substance had the tendency to develop into early testicular cord. Thus we made a conclusion that the time of gonad differentiation was the 5th hatching day in quail embryo at the histological level.3 We performed histological methods to learn the development of quail gonads, the pattern of gonads differentiation, as well as different character of testis organizational structure at all stages. The results showed: At the stages of 7th-9th hatching day, the morphological characteristics of testis was obvious; At the stages of 10th hatching day, the testicular cord formed and the PGCs had been differentiated into spermatogonium; At the stages of 12th hatching day, the number of spermatogonium showed likely clusters of grape or chain in the middle of seminiferous. In this stage, the fewer sustentacular cells had been differentiated, filling between the seminiferous together with the vascular; At the stages of 15th hatching day, the seminiferous become thicker and the number of spermatogonium increased accompanied by mitosis. At the stages of 17th hatching day, the morphology of testicular tend to be more mature, more sustentacular cells,connective tissue and vascular filled between the seminiferous.4 To study the development of ovary in quails'embryos, we sliced up the quails'embryos or gonads and dyed H.E. The results showed that: on the 7th hatching day, the right ovary began to degenerate, just a few PGCs began to differentiate into ooqoniums; and on the 10th day, the division between skinniness and medulla was obvious, and there were many ooqoniums in the ovary, some which were surrounded by some other cells distributed like circles; on the 11th day, there were more ooqoniums, the skinniness became thicker while the medulla was thinner; on the 13th day, the ovary formed the early original ovum; on the 14th day, more original ovums were seen in the skinniness; on the 17th hatching day and on the 1st day of hatching out, the shape of ovary tended to be mature, also the ovum was clear and more, while the medulla was full of vessels. We also observed the primary follicles and secondary follicles. Inter folliculars are rich in matrix.5 Currently, hot spots research of transgenic tecnology in poultry is mostly in the chicken. Quail as an experimental animal has the merit of being selected in this experiment as a reason for the experimental marerial. To fill the blank and to perform transgenic tecnology and embryonic stem cell technology in the quail, we need to know the basic theory for early embryo development in vivo. Further more, it is nessesary to research on the law of the origin, migration and proliferation of early PGCs system as well as the law of gonadal differentiation and development. Our experiment optimized the identification of early quail PGCs, the results showed a good immunofluorescent staining.