Figure 1.

The long-term feeding of cuprizone has a profound effect on the mature oligodendrocyte population. Paraffin-embedded sections were immunostained with anti-GST-pi (green cells; A–F), while some sections were also examined for the presence of apoptotic cells (red nuclei; E–F). A: A large number of GST-pi⁺ oligodendrocytes were observed within the corpus callosum in untreated control mice. B: The GST-pi⁺ oligodendrocytes were almost completely absent at 5 weeks. The GST-pi⁺ oligodendrocytes reappeared 4 weeks after 6 weeks of cuprizone feeding (C) and after 12 weeks of continuous cuprizone feeding (D). No apoptotic GST-pi⁺ oligodendrocytes were identified 4 weeks after the mice were returned to a normal diet following 6 weeks of cuprizone feeding (E). A large number of apoptotic nuclei were co-localized with GST-pi⁺ oligodendrocytes after 10 weeks of cuprizone feeding (F). Scale bar, 25 μm.