ABSTRACT
Objective To explore the optimal condition of direct differentiation into dopaminergic neurons of embryonic stem cells in serum-free and feeder layer cell free medium. Methods We used the method of phase induction to culture embryonic stem cells. At first, embryonic stem cells were cultured in the serum-free medium with bFGF and LIF so as to realize the direct differentiation from embryonic stem cells to neural precursors. Differentiated cells were determined by nestin immunocytochemical staining. On this basis, we transferred embryonic stem cells to the B27 serum-free medium with IL-1 so as to realize the direct differentiation from neural precursors to dopaminergic neurons. Differentiated cells were determined by TH immunocytochemical staining. Results Approximately 85 percent of cell masses were nestin immuno-positive. The differentiation ratio of dopaminergic neurons was 13%, which increased significantly in comparison with natural differentiation ratio of dopaminergic neurons.Conclusion Without serum and feeder layer cell, we can induce embryonic stem cells to differentiate into dopaminergic neurons effectively by adding different growth factors at different phases, which makes the inductive processes more easily.