Abstract
Background
The corpus callosum (CC) is a principal site of white matter pathology in multiple sclerosis and a common target for experimental demyelination–remyelination studies. The cuprizone model produces reproducible oligodendrocyte loss and myelin depletion, enabling controlled analysis of regional myelin dynamics.
Materials and Methods
Thirty male C57BL/6 mice (8 weeks old) were randomized to control (n = 10), demyelination (0.2% cuprizone, 5 weeks; n = 10), or remyelination (0.2% cuprizone, 5 weeks, followed by 5 weeks of recovery; n = 10) groups. Coronal sections spanning bregma +0.98 to +0.02 were stained with Luxol Fast Blue (LFB) and the CC was subdivided into medial (CC-M) and lat-eral (CC-L) regions. Every fifth section was analyzed (15 sections per brain), generating 150 quantified fields per subregion. LFB intensity was quantified and group comparisons were performed using the Kruskal–Wallis test with Dunn’s post hoc analysis (α = 0.05).
Results
Cuprizone exposure produced marked, regionally heterogeneous demyelination: morphologically, LFB signal was greatly diminished with pallor, thinning of the myelin band and focal signal loss, changes that were more pronounced in CC-L than CC-M. Quantitatively, mean whole-CC LFB intensity fell significantly after cuprizone (Kruskal–Wallis p < 0.0001); post hoc tests showed control vs demyelination (p < 0.0001) and demyelination vs remyelination (p < 0.0001), whereas control vs remyelination did not differ significantly (p > 0.05). Subregional analyses mirrored the overall pattern (p < 0.0001 for CC-M and CC-L), and revealed a sig-nificant medio-lateral difference during demyelination with CC-L < CC-M (p = 0.03). After five weeks of recovery, LFB intensity increased in both subregions but myelin bands remained thinner and more heterogeneous than in controls.
Conclusions
Five weeks of cuprizone elicited robust, spatially selective CC demyelination with greater lateral vulnerability; toxin withdrawal yielded substantial but structurally incomplete remyelination. These results emphasize the need for region-specific, multimodal assessment when evaluating remyelination and support targeting both OPC differentiation and mechanisms that improve myelin maturation and debris clearance in therapeutic strategies.