Defective remyelination in the spinal cord of Myd88^−/− mice. (A and B) OPCs in demyelinated lesions in mouse spinal cords at 7 dpi. The nuclei of OPCs were identified by the expression of both NKX-2.2 (magenta) and OLIG2 (green; colocalization, white). n = 3–9 lesions. (C and D) Premyelinating oligodendrocytes expressing BCAS1 (green) in mouse spinal cord lesions at 7 dpi. n = 4–10 lesions. (E and F) Mature oligodendrocytes expressing both APC (CC1; magenta, cytoplasm) and OLIG2 (green, nucleus) in mouse spinal cord lesions at 21 dpi. n = 3–7 lesions. (G and H) Remyelination in mouse spinal cord lesions at 21 dpi, quantified by the density of remyelinated axons in semi-thin sections. n = 4–6 lesions. Data are mean ± 95% CI (error bars) in B, D, and F or SEM in H. *, P < 0.05; ****, P < 0.0001 by two-way ANOVA test, with Sidak’s multiple comparisons test in B, D, and F and unpaired t test with Welch's correction in H. Scale bars: 100 µm in A, C, and E; 10 µm in G.