The cuprizone animal model: new insights into an old story

Multiple sclerosis (MS) is a chronic, inflammatory, demyelinating disease that affects the central nervous system and represents the most common neurological disorder in young adults in the Western hemisphere. There are several well-characterized experimental animal models that allow studying potential mechanisms of MS pathology. While experimental allergic encephalomyelitis is one of the most frequently used models to investigate MS pathology and therapeutic interventions, the cuprizone model reflects a toxic experimental model. Cuprizone-induced demyelination in animals is accepted for studying MS-related lesions and is characterized by degeneration of oligodendrocytes rather than by a direct attack on the myelin sheet. The present article reviews recent data concerning the cuprizone model and its relevance for MS. Particular focus is given to the concordance and difference between human MS patterns (types I-IV lesions) and cuprizone-induced histopathology, including a detailed description of the sensitive brain regions extending the observations to different white and grey matter structures. Similarities between pattern III lesions and cuprizone-induced demyelination and dissimilarities, such as inflamed blood vessels or the presence of CD3+ T cells, are outlined. We also aim to distinguish acute and chronic demyelination under cuprizone including processes such as spontaneous remyelination during acute demyelination. Finally, we point at strain and gender differences in this animal model and highlight the contribution of some growth factors and cytokines during and after cuprizone intoxication, including LIF, IGF-1, and PDGF alpha.