Abstract： Trophoblast (TR) plays an important role in the process of embryo implantation and placenta development. Molecular mechanisms of TR cell differentiation and lineage formation is an important tool to study the placental development. In this study, TR cells from porcine (Sus scrofa) in vitro fertilized (IVF) blastocysts (IVF-TR) were established and had been characterized, and the differences of some gene expression between in vivo porcine TR cells and in vitro TR cells were investigated by qRT-PCR. The IVF blastocysts which were derived from trophoblast cells exhibited typical trophoblast characteristics and displayed epithelium-like morphology, and trophoblast cell marker factors expressed such as keratin 18 (KRT18), keratin 7 (KRT7) and stage specific embryonic antigen 1 (SSEA1) by immunofluorescence analyses. The result of morphologic observation showed that porcine placenta was diffuse epitheliochorial placenta with atrophy at the peripheral tips, which was easy to be stripped from the uterine wall. The cells which were derived from the placenta were elongated spindle shape, epithelial like, grew slowly, and only passaged twice in vitro. The results of qRT-PCR which performed on porcine trophoblast cells from different sources showed that the expression of certain genes were different among trophoblasts. The expression levels of caudal homeobox transcription factor 2 (CDX2), pregnancy-associated glycoprotein (PAG) and GATA binding protein 3 (GATA3) were extremely higher in placenta trophoblast than that in IVF-TR cells (P＜0.05), while heart and neural crest derivatives expressed 1(HAND1), KRT18 and cadherin 3 (CDH3) expression which were associated with TR differentiation and implantation were extremely lower in placenta trophoblast than that in IVF-TR cells (P＜0.05). Apart from TEA domain family member 4 (TEAD4), the expression levels of other trophoblast genes were lower in the placenta cells than that in placenta tissues and IVF-TR. In conclusion, the IVF-TR cells were more like early differentiated TR cells, and the gene expression was different from the mature late trophoblast cells in placenta. At the same time, the gene expression of the in vitro cultured placenta cells was also different from the placenta tissues. This study indicated the IVF-TR cells might be used as the material and tool to investigate the trophoblast differentiation and the development of porcine placenta. The results provide the preliminary assessments data for the further investigation.
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