Neuroprotective effects of ellagic acid on cuprizone-induced acute demyelination through limitation of microgliosis, adjustment of CXCL12/IL-17/IL-11 axis and restriction of mature oligodendrocytes apoptosis

Context: Ellagic acid (EA) is a natural phenol antioxidant with various therapeutic activities. However, the efficacy of EA has not been examined in neuropathologic conditions. Objective:In vivo neuroprotective effects of EA on cuprizone (cup)-induced demyelination were evaluated. Material and methods: C57BL/6 J mice were fed with chow containing 0.2% cup for 4 weeks to induce oligodendrocytes (OLGs) depletion predominantly in the corpus callosum (CC). EA was administered at different doses (40 or 80 mg/kg body weight/day/i.p.) from the first day of cup diet. Oligodendrocytes apoptosis [TUNEL assay and myelin oligodendrocyte glycoprotein (MOG(+))/caspase-3(+) cells), gliosis (H&E staining, glial fibrillary acidic protein (GFAP(+)) and macrophage-3 (Mac-3(+)) cells) and inflammatory markers (interleukin 17 (IL-17), interleukin 11 (IL-11) and stromal cell-derived factor 1 α (SDF-1α) or CXCL12] during cup intoxication were examined. Results: High dose of EA (EA-80) increased mature oligodendrocytes population (MOG(+) cells, p < 0.001), and decreased apoptosis (p < 0.05) compared with the cup mice. Treatment with both EA doses did not show any considerable effects on the expression of CXCL12, but significantly down-regulated the expression of IL-17 and up-regulated the expression of IL-11 in mRNA levels compared with the cup mice. Only treatment with EA-80 significantly decreased the population of active macrophage (MAC-3(+) cells, p < 0.001) but not reactive astrocytes (GFAP(+) cells) compared with the cup mice. Discussion and conclusion: In this model, EA-80 effectively reduces lesions via reduction of neuroinflammation and toxic effects of cup on mature OLGs. EA is a suitable therapeutic agent for moderate brain damage in neurodegenerative diseases such as multiple sclerosis.