Figure 3: Effects of IFN-β and SNP, an donor, on the viability of neuronal PC12 cells. Neuronal PC12 cells (  cells/well) were treated with or without recombinant IFN-β (a) or SNP, an donor (b), for 24 h at 37°C. Cell viability was determined using a colorimetric assay with WST-8 reagent as described in the Methods section. Data are presented as values relative to those obtained in cells treated with vehicle and are expressed as ( ). * , ** compared with vehicle.