Effects of dietary intervention on MRI activity, de- and remyelination in the cuprizone model for demyelination

Whether differences in diet composition may influence demyelinating diseases remains controversial. The aim of this study was to analyse if diets with a different composition of polyunsaturated fatty acids (PUFAs) could influence demyelination and remyelination in cuprizone fed mice, a widely used animal model for de- and remyelination. C57Bl/6 mice were fed with 0.2% cuprizone on three different diets. The diets consisted of the same ingredients, except the lipid source, which came from 1) salmon fillets rich in marine n-3 polyunsaturated fatty acids (PUFAs), 2) cod liver oil rich in marine n-3 PUFAs, or 3) a control diet containing soybean oil rich in n-6 PUFAs. After 5 weeks of cuprizone treatment, the mice given salmon-cuprizone had significantly less hyperintense lesion volume on brain magnetic resonance imaging (MRI) than the two other groups (P<0.0005). After 6 weeks of cuprizone treatment, the salmon-cuprizone group had less demyelination in the corpus callosum, as measured with luxol fast blue (LFB) (P<0.0005) and anti-proteolipid protein (PLP) (P=0.014). The salmon-cuprizone group also had enhanced remyelination compared to the cod liver oil-cuprizone group (LFB; P=0.003, PLP; P=0.018). This study indicates that a fish rich diet may offer a protective role in demyelination. The source of N-3 PUFAs, or other components in the fish, may be important, as no effect of a cod liver oil based diet was observed. This may be of importance related to the discrepant results in dietary intervention studies for demyelinating diseases.