Fig. 1
DMF treatment attenuates the severity of EAN. EAN was induced in rats by immunization on day 0 with P0 peptide 180-199 (300 μg) emulsified in complete Freund’s adjuvant and dissolved in vehicle. In a preventative treatment paradigm, DMF was administered from day 1 to day 27 (25 mg/kg, once daily). By contrast, in a therapeutic treatment paradigm, DMF was administered from day 7 to day 27 at the same 25 mg/kg dose, once daily. In a control condition, EAN rats received an equivalent volume of vehicle. Clinical scores (0–10, with 0 being normal to 10 being so severely impaired that the animals died) were obtained daily post-immunization. a EAN clinical scores were significantly better in DMF-treated groups, but the pattern of improvement over time was different. The rats in the preventative treatment group exhibited significantly better clinical scores from day 6 to day 27 compared with the rats in the CMC group (p < 0.05 on each time point). The rats in the therapeutic group had significantly better clinical scores from day 10 to day 27 compared with the rats in the CMC group (p < 0.05 on each time point). b–d DMF reduced the peak score, the day of disease onset, and the area under the curve (AUC) in EAN rats. On day 16 post-immunization, sciatic nerves of each group were harvested for H&E staining (e) and LFB staining (g) to assess changes in infiltration and demyelination. Representative photomicrographs are shown for each group. The mean number of inflammatory cells per square millimeter of tissue section was determined as described in the “Methods” section, and summaries are shown in f. Mean histological scores are shown in h. Scores were calculated as described in the “Methods” section. Comparisons between the CMC group and DMF-treated groups were performed using Mann–Whitney U tests. Arrows showed the inflammatory cells and the demyelination of sciatic nerves. Scale bar in e and g is 10 μm. The results are presented as means ± SEM (*p < 0.05 for comparison between CMC and DMF-treated groups, n = 6 per group). CMC vehicle control group, DMF-P preventative DMF group, DMF-T therapeutic DMF group. The experiment was repeated 3 times with similar results