Immunostaining of induced pluripotent stem (iPS) cell-derived cardiomyocytes. (A–F): Microscopic images showing differentiated cells on day 15 in the no-glucose DMEM-untreated group (A, C, E) and in the no-glucose DMEM-treated group (B, D, F). (A, B): Immunostaining of SSEA-1 (green). Nuclei were stained with DAPI (blue); DsRed (red) was expressed in the cytosol of iPS cell-derived cells. Scale bars = 100 μm. (C, D): Immunostaining of α-actinin (green). Nuclei were stained with DAPI. Scale bars = 300 μm. (E, F): Immunostaining of Nkx2.5 (green) and DsRed (red) expression in the cytosol of iPS cell-derived cells. Scale bars = 300 μm. (G): Quantification of α-actinin- and Nkx2.5-positive cells by imaging analysis. In the no-glucose DMEM-untreated group (gray columns), the percentages of α-actinin- and Nkx2.5-positive cells were 37.87% and 27.92%, respectively. In contrast, the percentages of α-actinin- and Nkx2.5-positive cells in the no-glucose DMEM-treated group (red column) were 99.18% and 96.45%, respectively. *, p < .05. Abbreviations: DAPI, 4′,6-diamidino-2-phenylindole; DMEM, Dulbecco's modified Eagle's medium; DsRed, Discosoma red fluorescent protein; SSEA, stage-specific embryonic antigen.