Cuprizone-Induced Demyelination and Remyelination

The 8–10 week old mice were fed with a standard rodent chow with 0.25% (w/w) cuprizone (bis (cycloheanone) oxaldihydrazone; Sigma) for 5 weeks to induce the demyelination in mouse brains, followed by the switch to the normal chow for 2 additional weeks to allow the recovery from demyelination. The cuprizone-induced demyelinated or remyelinated mice were anesthetized, perfused with PBS, followed by fixation with 4% PFA. The whole mouse brains were removed, post-fixed, sectioned at 30 μm using a vibratome, and subjected for the oil-red O staining, immunohistochemical analysis and electron microcopy analysis. In consideration of the cuprizone induced lesions are in the variability in lesion size and location, the corresponding section every ten serial coronal sections in the corpus callosum of mice was selected and 6–8 sections in one brain were stained for analysis. For the motor coordination assessment, the 8–10 week old mice first received a training of running on a rotating rod at an accelerating speed from 4 to 40 rotations per min for 300 s for 1 week (Harvard apparatus, UK). The mice that could still stay on the rotating cylinder at a speed of 4 rotations/min for 300 s were used for the following motor coordination analysis. The latency to fall off a rotating rod at a speed of 4 rotations/min and the body weight of each mouse were measured every 3 days during the 5 weeks’ cuprizone chow feeding and following 2 weeks’ normal chow feeding.