Strain differences in cuprizone induced demyelination.

Background: Multiple sclerosis (MS) is a severe neurological disorder, characterized by demyelination of the central nervous system (CNS), and with a prevalence of greater than 2 million people worldwide. In terms of research in MS pathology, the cuprizone toxicity model is widely used. Here we investigated the contribution of genetic differences in response to cuprizone-induced demyelination in two genetically different mouse strains: CD1 and C57BL/6.

Results: We demonstrate that exposure to a diet containing 0.2% cuprizone resulted in less severe demyelination in the midline of the corpus callosum over the fornix in CD1 mice than C57BL/6 mice. With continuous cuprizone feeding, demyelination in CD1 mice was not prominent until after 7 weeks, in contrast to C57BL/6 mice, which showed prominent demyelination after 4 weeks of exposure. Concomitantly, immunohistochemical analysis demonstrated more oligodendrocytes, as well as fewer oligodendrocyte progenitor cells, microglia and astrocytes in cuprizone treated CD1 mice. We also analyzed 4-weeks-cuprizone treated corpus callosum tissue samples and found that cuprizone treated CD1 mice showed a smaller reduction of myelin-associated glycoprotein (MAG) and a smaller increase of Iba1 and NG2.

Conclusions: These observations suggest that CD1 mice are less vulnerable to cuprizone-induced demyelination than C57BL/6 mice and thus genetic background factors appear to influence the susceptibility to cuprizone-induced demyelination.