| The testis is the basis for male animals to obtain and maintain fertility.A full understanding of the developmental characteristics of the testis is essential for understanding spermatogenesis and improving male fertility.The characteristics of testicular development and spermatogenesis in mice and humans are relatively clear,however,the characteristics of testicular development in pigs are currently unclear.Therefore,it is necessary to explore the characteristics of pig testicular development.This study collected 7,30,50,70,90,110,130,150,and 210-day-old pig testicular tissues.With the help of histomorphological observation and immunohistochemical staining,the differentiation process of pig testicular spermatogonia and Sertoli cells was explored.The main findings are as follows:1.The diameter of seminiferous tubules gradually increases with increasing age,and increases faster after 110 days of age.At 130 days of age,spermatids and round sperm cells were observed for the first time in pig seminiferous tubules and sperm and the lumen of seminiferous tubules were first observed at 150 days of age.2.At the age of 110 days,all gonocytes have transferred to the base of seminiferous tubules,marking the completion of their transformation into undifferentiated spermatogonia.At 110 days of age,UCHL1~-/VASA~+cells were first observed in seminiferous tubules,marking that undifferentiated spermatogonia began to differentiate.By immuno-dual fluorescence staining of UCHL1/Ki-67 and c-kit/PCNA,it was found that most gonocytes had no proliferation characteristics at 7 days of age,while most c-kit-positive gonocytes showed proliferation characteristics.After 30 days of age,most gonocytes and undifferentiated spermatogonia showed proliferation characteristics,while all c-kit positive cells also showed proliferation characteristics.3.Immature Sertoli cells(AMH~+/SOX9~+)in pig testes mature(AMH~-/SOX9~+)at 110days of age.The number of Sertoli cells in the cross section of seminiferous tubules was 17.6and 22.6 at 7 and 30 days,respectively,and remained basically unchanged after that.The number of Sertoli cells(SOX9~+/PCNA~+)showing proliferation characteristics in the transverse section of seminiferous tubules was 13.5,6.6,8.2,5.8,1.0 at 7,30,50,70,and 90days old,respectively,and 0 thereafter.In summary,this study explored the dynamic changes of spermatogonia and Sertoli cell molecular markers in pig testis,and ascertained the differentiation characteristics of spermatogonia and Sertoli cells.This study will provide a theoretical reference for in-depth elucidation of pig spermatogenesis. |
