Fig. 8

ISP treatment promoted oligodendrocyte outgrowth and myelination through the Erk–CREB signaling pathway. a Representative images of oligodendrocytes in the presence of aggrecan in Control (PDL only), Agg (PDL + aggrecan), ISP (aggrecan + ISP), and Erk inhibitor (aggrecan + ISP + U0126) groups as indicated. b Statistic showed a significant reduction in oligodendrocyte outgrowth in the aggrecan group relative to the control group, which could be reversed by ISP application. Moreover, inhibition of Erk with U0126 counteracted the elevation caused by ISP treatment. n = 5 per group. Scale bar, 50 µm. c, d, e Western blot assay of p-Erk and p-CREB expression in cultured oligodendrocytes of the four groups. Data are normalized to GAPDH expression, n = 3 per group. f, g Representative immunofluorescent images of NF200 (red) and MBP (green) show aggrecan suppressed myelination by oligodendrocytes, which could be reversed by ISP via the Erk signaling pathway, n = 8–10 from 4 to 5 independent replicates per group. Scale bar, 100 µm. Data were analyzed by one-way ANOVA followed by Tukey’s multiple comparisons test, and expressed as mean ± SD. *p < 0.05, **p < 0.01, ***p < 0.001