Abstract: Objective To investigate the developmental feasibility of early human fetal testes (<3 months) using xenografting technique and to acquire an accessible donor derivation that is essential for studying human germ cell development. Methods Nine testes from 10-13 weeks aborted fetus were grafted under the back skin of 6 castrated nude mice. Grafts were collected at different time point according to the growth of the donor tissues and the health condition of the recipients. Morphological and histological analyses were performed for the observation of the development of grafted immature testicular tissues. Results The mass of grafts was increased from about 5-7mg to 84.1mg (the biggest). Six of 9 testes were to be in developing. Histological observations showed a significant expansion of seminiferous tubules from (44.26±3.14)μm to (77.69±7.47)μm. Cells dispersedly distributed in seminiferous cords at the time of grafting migrated towards the basal part of seminiferous epithelium. Some germ cells with spermatogonium-like characteristics located on the basement membrane. Sertoli cells were in stages from immature into matured with abundant cytoplasm which were orderly arranged around spermatogonia forming a niche-like structure. Conclusion Testes from early aborted human fetus grafted under the back skin of castrated nude mice showed further development and therefore could be used as an easier accessible donor tissues for the investigation of hu

Key words: Testis, Germ cell, Development, Xenografting, Histology, Nude mouse, Human fetus