Laminin promotes in vitro outgrowth of mouse trophoblast from blastocysts cultured in hanging drop

Abstract

Differentiation of the nonadherent trophectoderm cells of the mammalian embryo into attachment-competent trophoblast cells appears to be a necessary event for invasion of the uterine stroma. We have used a hanging drop culture system to investigate the involvement of contact with a solid surface and extracellular matrix proteins on mouse trophoblast differentiation. We report that laminin, but not fibronectin, promotes in vitro outgrowth of mouse trophoblast without attachment of the embryo to a solid surface, in a serum free culture medium. This result indicates that, in the presence of a trophoblast differentiation factor, the contact of the embryo with a solid surface is not necessary to obtain in vitro trophoblast differentiation.