Development of an in vitro model for bovine placentation: a comparison of the in vivo and in vitro expression of integrins and components of extracellular matrix in bovine placental cells.

BACKGROUND/AIMS: Interaction of trophoblastic integrins with the extracellular matrix plays a role in embryo implantation and trophoblast invasion. The phenomenon of restricted trophoblast invasion, observed in the bovine epitheliochorial placenta offers intriguing conditions to study invasive processes. The migration of bovine trophoblast giant cells is accompanied by the expression of specific integrins and corresponding extracellular matrix ligands.

METHODS

Primary cultures of different cell populations from cow placentomes were established and characterized, and in vitro phenotypes were compared with in vivo conditions by immunofluorescence.

RESULTS

Propagated epithelial cells were positive for cytokeratin and vimentin, while fibroblasts contained alpha-smooth muscle actin, desmin and vimentin. Epithelial cells coexpressed integrin subunits alpha(6) and beta(1) with laminin, and fibroblast cells were positive for alpha(v), beta(3), fibronectin and laminin. In contrast to cells in vivo, cultured epithelial cells secreted fibronectin, while collagen IV was not detected. The occurrence of integrin subunits was confirmed at mRNA level by RT-PCR.

CONCLUSION

We have established cell cultures isolated from maternal and fetal components of bovine placentomes expressing typical cytoskeletal filaments and integrin receptors also present in their in vivo counterparts. These bovine placentomal cells provide a suitable in vitro model for the study of cell-cell interactions.