INDUCTION OF NEUROBLAST DIFFERENTIATION IN EMBRYO-DERIVED TERATOMAS IN VITRO

When mammalian embryos without extraembryonic membrones are cultivated at the air liquid interface in a modified organ culture, they develop into teratoma-like explants during two weeks. To investigate the impact of neuroblast differentiation-inducing agents, retinoic acid (RA), nerve growth factor (NGF), dibutyryl cyclic AMP (db-cAMP) and 5-azacytidine (5azaC), they were added in various concentrations to culture media for various time of action. Retinoic acid did not influence differentiation of neurablasts over 2, 7 or 14 days, nor did the combination treatment with RA and db-cAMP. Various concentrations of NGF did not stimulate the differentiation of neurnblasts as we expected. Treatment with 5azaC during 24 hours followed by RA treatment did not induce any improvement of neuroblast differentiation either. On the contrary, differentiation of neuroblasts was significantly improved when the embryos were treated with a combination of 5azaC and 200 ng/ml of NGF. In cultivated teratomas, NGF-induced neuronal differentiation depended on the gene status and NGF dose used.