Figure 2

The time course of axonal degeneration for hydrogen peroxide exposure. Neurons were treated with 100 μM hydrogen peroxide (or PBS as control) for up to 24 h, and axonal morphology was monitored by neuron-specific beta3-tubulin staining. After one hour, cells remained normal (B). After 3 h, many axons started to show signs of degeneration as indicated by swelling of the axons (C); by 9 h, the axons exposed to hydrogen peroxide were completely fragmented (D). In contrast, neurons in the mock-treated culture remained intact even 24 h later. Scale bar, 20 μm.