Histomorphological Study During Development Of Chicken Embryonic Gonad

Because of the sex determination and the molecular mechanism of gonadal development of chicken are not very clear make the gonadal development process and its molecular regulation are important research directions in chickens.At present,the study of chicken gonad has been deepened to all aspects,most of the study focus on molecular regulation of gonadal development mechanism,however,there are few systematic studies on the basic morphological of chicken embryonic gonadal stage.Only a very small number of scattered research reports,but if there is no normal basic histomorphology as the reference standard,it is difficult to judge the effect of experiment operation,so the systematic study of chicken embryonic gonadal histomorphology is particularly important.Based on this situation,this topic proposed to collect the entire incubation period of different age chicken embryo gonads with the interval of 0.5 days.Grouping by sex identification,then used paraffin section or frozen section.We treated the slice with HE staining,and observe the basic morphology of gonadal tissues under different magnification to know the basic structural components of male and female gonad and the difference between them.PAS staining,SSEA-1 immunohistochemistry and c-Kit immunohistochemistry were used to track the changes of germ cells.Oil red O staining,FOXD1 immunohistochemistry and SOX9 immunohistochemistry were used to analysis the generation time and morphological changes of sertoli cells.By qualitative analysis of several major cells and gonadal structures in the male and female gonads,we hope that we can enrich the state of gonad from the basic tissue level during the whole incubation period and it’s changing trend.Also reveal the differentiation or formation time of several major cells,so as to provide a basic control for the future study of chicken gonadal morphology.The main results of this study are as follows:(1)HE staining showed that the size of gonads between left and right were different both in female and male chicken embryo,but the gonads had developed on both sides of the male,and the difference was very small.However,the female was only developed on the left,the right side was degraded.(2)HE staining found that male gonad was not divide into cortical layer and medulla layer,it contains a large number of tubular structure,which will be visited in the eighth day of embryonic.It is obvious that female gonad have cortical layer and medulla layer,and medulla layer close to the kidney.In the 6.5 day of embryonic periods cortical layer has been clearly seen.The medulla layer contains a large number of vacuolar structures,which were visible on day 8 of the incubation period.(3)The result of PAS staining and SSEA-1 immunohistochemistry showed that the primordial germ cell lines in male gonad were completely differentiated in about 12.5th day of incubation period.The female gonadal germ cell lines were completely differentiated on the 11 th day of incubation period.(4)Oil-red O staining,SOX9 immunohistochemistry and FOXD1 immunohistochemistry results showed that the sertoli cells formed in the incubation period of about 6.5th day.The initial nucleus is large,round,and then split into multiple,the size has been reduced.(5)In this study,we obtained the map of HE staining,oil red O staining and FOXD1 immunohistochemistry from 6.5th to 19 th in embryonic,which laid a good foundation for the further study of chicken gonad in morphology.