Cell survival and metabolic activity in irradiated hES, iPS and iPS-hNSCs.

<p>Exponentially growing hESCs, iPSCs and iPS-hNSCs were seeded at densities of 65,000, 84,000 and 50,000 cells/well respectively. Cell counts were quantified by SYBR green-based fluorescence. The number of stem cells exhibited a dose-dependent decline 5 days after irradiation (A, D and G). The global metabolic activity measured in the same cells using the XTT assay showed a similar dose-dependent decline for hESCs (B) and iPS-hNSCs (H). An opposite pattern was observed for iPSCs (E). Normalizing the global metabolic activity per million cells revealed a dose-dependent increase in cellular metabolism for all cell types (C, F, I). Data expressed as the Mean ± S.E.M. of 3–4 independent observations compared to unirradiated controls. *, <i>P</i><0.05 and **, <i>P</i><0.01.