Ameliorating EAE progression and promoting remyelination by overexpressing MSX3 in microglia. EAE mice were given injections of PBS (Sham EAE), MSX3 overexpressing microglia (MSX3OE MG), or control lentivirus-transduced microglia (CtrlOE MG) into the right lateral ventricle (day 22 after immunization). A, The clinical score of EAE was shown for each transplantation group. The data represent average disease scores from five to eight mice per group, using Kruskal–Wallis test with Dunn's post hoc test. ***p < 0.005 versus CtrlOE MG or sham EAE group. B–D, Overexpression of MSX3 in microglia promoted remyelination in spine cords. Spine cords from each group (MSX3OE and CtrlOE) of EAE mice were harvested at 40 d after EAE induction. The ventral column of the L4 lumbar spine cords was examined. B, Representative electron micrographs of the demyelinated lesions of spinal cords at 40 d after EAE induction. The presence of thin myelin sheaths (remyelination, arrows) was observed in both the MSX3OE MG and CtrlOE MG groups. In contrast, the normal thick myelin sheaths (arrowheads) were observed in naive mice. Original magnification, ×700; high magnification, ×1500. Scale bars: top, 5 μm; bottom, 2 μm. C, Quantification of myelinated axons among total axons. D, Mean g-ratio (axon diameter divided by entire myelinated fiber diameter) was determined using ImageJ software. *p < 0.05; **p < 0.01; ***p < 0.005 versus control, as indicated. Data are the mean ± SEM, using one-way ANOVA with Tukey's post hoc test. Five to eight mice (40 d after EAE induction) from each group were analyzed.