Attenuation of experimental autoimmune encephalomyelitis (EAE) in C57BL/6 mice by Licochalcone A

Multiple sclerosis (MS) is an autoimmune inflammatory and demyelinating disease of the central nervous system (CNS) that affects more than 2.5 million people worldwide. The experimental autoimmune encephalomyelitis (EAE) is an appropriate and a well-establish model for studying the pathogenesis of MS. Licochalcone A (LicoA) is a chalcone obtained from the roots of Glycyrrhiza inflata (Fabaceae) that has in vitro immunomodulatory effects. EAE was induced in C57BL/6 mice with myelin oligodendrocyte glycoprotein and we have investigated the treatment of LicoA in this animal model. LicoA was isolated from G. inflata and was orally administered during the development of EAE. The capacity of absorption and distribution of LicoA, after gavage, to the brain was performed by HPLC. The clinical course and body weight were performed daily, cytokines (ELISA) and oxygen radicals production (NO and H2O2) were investigated. The CNS sections were stained by hematoxylin and eosin. After the treatment, by HPLC, at the first time, we analyzed the penetration between tissue/plasma, and our results showed that LicoA was present in serum and reached the mice brain with a good distribution. LicoA reduced clinical score and severity of EAE-mice, as well as inhibited H2O2, NO, TNF-α, IFN-γ and, mainly, IL-17 production. Histopathological analysis confirmed that LicoA treatment significantly reduced the numbers of inflammatory infiltrates and attenuates neurological damages in the CNS. These findings demonstrate that the oral treatment of LicoA significantly ameliorated the inflammatory signs associated with EAE, since it is effective at reducing both disease onset and severity.