Evaluation strategy to determine reliable demyelination in the cuprizone model.

In multiple sclerosis patients, chronic clinical deficits are known to result from axonal degeneration which is triggered by inadequate remyelination. The underlying molecular mechanisms of remyelination and its failure remain currently unclear. In vivo models, among the cuprizone model, are valuable tools to study underlying mechanisms of remyelination and its failure. Since complete and reproducible demyelination of the analyzed brain region is an indispensable prerequisite for efficient remyelination experiments, in this study we systematically addressed which part of the corpus callosum is reliably and consistently demyelinated after acute cuprizone-induced demyelination. Following a novel evaluation strategy, we can show that at the level of the rostral hippocampus, the most medial sectors of the corpus callosum (spanning 500 μm in the horizontal plane) are consistently demyelinated, whereas more lateral sectors show inconsistent and incomplete demyelination. These results precisely define a part of the corpus callosum which should be used as a region of interest during remyelination experiments.