Cuprizone effect on myelination, astrogliosis and microglia attraction in the mouse basal ganglia

Multiple sclerosis is the leading cause of neurological disability in young adults affecting more than two million people worldwide. Although multiple sclerosis is generally considered as white matter disease, distinct pathological alterations are also found in the grey matter. Involvement of basal ganglia seems to be related to a set of symptoms such as fatigue, impaired cognition, and movement disturbance. Since no appropriate animal model for studying cortical deep grey matter demyelination is established, we reassessed the cuprizone mouse model to investigate basal ganglia demyelination. Mice were fed cuprizone for different time intervals. The myelin status was analyzed by classical histological staining and immunohistochemistry for myelin proteins and glia markers. Expression of oligodendrocyte and astroglia were investigated by PCR. Cuprizone intoxication induced a severe demyelination of distinct cortical deep grey matter sub-regions. Striosmomes, located within the caudate-putamen and the ventral part of the caudate nucleus displayed intense demyelination, whereas those within the globus pallidus and the head of the caudate nucleus were not affected. The matrix region, however, was equally affected in the medial and lateral region. Besides demyelination, we observed hypertrophic and hyperplastic astrocytosis and microglia cell invasion/local proliferation in the demyelinated areas. Young adult and aged mice were similarly affected as well as mice with different genetic backgrounds. We conclude that cuprizone-induced demyelination provides an adequate animal model to investigate appropriate therapy strategies for the prevention of cortical deep grey matter demyelination. The heterogeneity in local demyelination points at beginning remyelination during ongoing demyelination.