Amelioration of experimental autoimmune encephalomyelitis in Lewis rats treated with fucoidan.

We examined whether fucoidan affected the clinical symptoms of experimental autoimmune encephalomyelitis (EAE) in rats. EAE was induced in Lewis rats that were immunized with guinea-pig myelin basic protein (MBP) and complete Freund's adjuvant. Fucoidan (50 mg/kg, daily) was administered to rats with EAE intraperitoneally, either in the EAE induction phase from either 1 day before immunization to day 7 post-immunization (PI), or the effector phase from day 8 to 14 PI, to test which phase of rat EAE is affected by fucoidan treatment.The onset, severity and duration of EAE paralysis in the fucoidan-treated group in the days 8-14 PI-treated rats, but not in days -1-7 PI-treated rats, were significantly delayed, suppressed and reduced, respectively, compared with the vehicle-treated controls. Treatment with fucoidan reduced the encephalitogenic response and TNF-alpha production during EAE. Moreover, the clinical amelioration coincided with decreased infiltration of inflammatory cells in the EAE-affected spinal cord. The ameliorative effect of fucoidan on clinical paralysis in EAE-affected rats may be mediated, in part, by the suppression of the autoreactive T cell response and inflammatory cytokine production.