Activin A neither modifies cell number nor BrdU incorporation in proliferating conditions.

<p>Cells were kept in N2 medium with 10 ng/ml FGF2 and treated with Activin A, TGF-β1 or BMP4 during 4 days. In the MTT (<b>A</b>) or crystal violet (<b>B</b>) assays the resulting absorbances in experimental conditions are expressed as percentage of the control condition. <b>C:</b> Quantification of viable cells by trypan blue exclusion. Results are expressed as percent of cells that exclude the dye in relation to total cells. <b>D:</b> Representative images of the immunocytochemistry for Nestin (green) BrdU (red) and nuclei stained with Hoechst (blue), showing no changes in cell proliferation due to the treatment with the cytokines. <b>E:</b> Quantification of BrdU⁺ nuclei. The results are expressed as mean ±S.D. of the percent of total cells stained with Hoechst. Statistical comparisons were made by ANOVA followed by Student-Newman-Keuls test.