Effects of green tea epigallocatechin-3-gallate on the proteolipid protein and oligodendrocyte transcription factor 1 messenger RNA gene expression in a mouse model of multiple sclerosis

The cuprizone multiple sclerosis (MS) animal model is characteristic for toxic demyelination and represents a reversible demyelination and remyelination system. It has been shown that green tea epigallocatechin-3-gallate (EGCG) might be effective in improving the symptoms and pathological conditions associated with autoimmune inflammatory diseases in several animal models. In this study the effects of EGCG on proteolipid protein (PLP) and oligodendrocyte transcription factor 1 (Olig1) expression in the cerebral cortex of a murine model of cuprizone-induced demyelination was investigated. C57BL/6 mice were treated with cuprizone for six weeks in order to induce demyelination. Immediately after the cessation of cuprizone the animals were divided into 6 groups (n = 10 for each group). The first two groups were injected intraperitoneally (IP) with EGCG in the amount of 50 mg/kg/daily body weight for 2 and 4 weeks. The second two groups (SHAM) were injected IP with phosphate-buffered saline (PBS) for 2 and 4 weeks, and the third two groups were left without injection as controls. After two and four weeks the mice were killed and the cerebral cortex was collected and the expression of Plp and Olig1 was studied by real-time PCR. The results showed significant increases in PLP and Olig1 expression in the EGCG-treated groups as compared to the SHAM and control groups (p < 0.0001). It is concluded that EGCG increases PLP and Olig1 expression in the cerebral cortex of a mouse model of MS induced by cuprizone