Direct hepatic differentiation of mouse embryonic stem cells induced by valproic acid and cytokines

Figure 6 VPA-induced cell cycle arrest and apoptosis during hepatic differentiation. A: Cell cycle analysis revealed that exposure to VPA decreased the proportion of cells in S phase and increased the proportion of cells in the G0/G1 phase. Approximately 75% of the cells were arrested in the G0/G1 phase and only 10% of the cells in the S phase after 6 d of treatment with 1 mmol/L VPA, whereas greater than 37% of control ES cells were in the S phase; B: The analysis of apoptosis proportions during 3 d of treatment with VPA; C, D: Ultrastructural observations showed that some cells presented typical apoptotic morphology when treated with VPA for more than 5 d.