engleski

INDUCTION AND DEVELOPMENT OF EMBRYO-DERIVED TERATOMAS IN VIVO AND IN VITRO

Experimental teratomas can be obtained by implantation of early mammalian embryos in extra-uterine sites in experimental animals or in vitro. The resulting teratoma provides evidence on the conditions necessary for differentiation and formation of embryo-derived teratocarcinomas. We have investigated the development of rat gastrulating embryo-derived teratomas in vivo beneath the kidney capsule and in vitro using an original culture method, devised in our laboratory, where embryos grow at the air-liquid interface for two weeks. The study deals with two points: determination of differentiation or creation of conditions that propagate undifferentiated embryonic cells without differentiation. Thus, we analyzed the sequence of events leading to the terminally differentiated tissues in explants in vitro during two weeks or whether they are left undifferentiated. The level of differentiation in vitro was slightly inferior to that seen in kidney grafts, especially in serum-free medium, which permits very little growth and limited differentiation of only few tissues. The overt differentiation began on the 5th day and the embryos in all extrauterine sites followed the rule "more or less' differentiation, rather than a "more or none&#8221 ; reaction. The number of differentiated tissues progressively increased during the second week of growth. Undifferentiated embryonic cells were not found in rat embryo-derived teratomas grown in vitro or in vivo, but we could not exclude the possibility of obtained retransplantable teratomas.

teratoma; embryo organ culture; cell differentiation; embryo transfer

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