Abstract: Objective To establish mice tetraploid trophoblast stem cell(TTSCs) line which could be cultured in vitro, providing a new cell model for the research of placenta development. Methods Tetraploid embryos were produced by electrofusion and cultured in vitro, clones were picked up and passaged to establish cell lines. Metaphase chromosome counting was used to detect the chromosome number. RT-qPCR, Western blot and immunofluorescence were used to detect the expression of marker genes. Microinjection was used to detect the development potential in vivo. Results TTSCs that can develop in vivo and be passaged were established. The expression of differentiation genes was distinct between TTSCs diploid TSCs under differentiation condition. Conclusions Passable cell line TTSCs could be established in vitro, but the mechanisms of self-renew and differentiation were different between TTSCs and diploid TSCs.

Key words: tetraploid, trophoblast stem cell, embryogenesis, placenta development, differentiation