Figure 3. The change of the cell membrane permeability of NPCs caused by hydrogen peroxide. (A) Hochest33342/PI double staining revealed hydrogen peroxide (200μM, 3h) increased the PI positive nucleus pulposus cells (magnification: ×10, scale bar = 200μm). (B) The scanning electron microscopy showed that ball-like bulge and membrane pore-forming were increased by hydrogen peroxide.