Comparisons of myelination among different time points in spinal cord cultures were performed using analysis of variance (ANOVA) followed by post hoc Tukey’s analysis. The significant level is set to 0.05. Results Myelination in the spinal cord derived culture Defining an optimal culture condition First, we followed in principle the protocol described

for the myelination culture derived from Inhibitors,research,lifescience,medical embryonic mice spinal cord (Thomson et al. 2008), and N2 was used as the myelination medium. Four weeks later, the culture was double immunostained with MBP (to label myelinated axons, but also labels OL cell bodies and processes) and Tuj1 (to label neurites) antibodies to visualize myelin segments (Fig. 1). In agreement with the previous signaling pathway report, very few myelin segments, if any, were found in cultures Inhibitors,research,lifescience,medical derived from the rat spinal cord. The overall density of Tuj1+ neurites was low. However, MBP+ mature OLs were

in abundance. Since NBM (with B27 supplement), which is a standard medium for neuronal culture, has been shown to support OL differentiation (Yang et al. 2005), it was then chosen as a substitute for N2. Inhibitors,research,lifescience,medical As expected, the density of neurites was indeed significantly improved and the number of MBP+ OLs seemed to be slightly less than in N2 at DIV13. Although myelination was also improved, the numbers of myelin segments remained lower compared to the mice study (Thomson et al. 2008). Interestingly, a combination of N2 and NBM (at a ratio of 1:1) culture medium revealed an extensive number of myelin Inhibitors,research,lifescience,medical segments (Fig. 1I) compared to either N2 or NBM alone. This synergetic effect of N2 and NBM on myelin formation appeared primarily due to their improvement on OL development, as most of the premyelinating OLs in N2+ NBM developed longer and finer processes (Fig. 1H) than from either N2 (Fig. 1B) or NBM Inhibitors,research,lifescience,medical alone (Fig. 1E). Figure 1 Defining an optimal condition for myelination cultures from E16 rat spinal cord. Cultures maintained in N2 showed poor density of neurite (A), high density of mature Tolmetin OLs (B), but very few myelin segments

(arrow heads in C). In contrast, NBM showed a markedly … Neuron/glia development and myelin formation After establishing the optimal culture condition, we next characterized the spinal cord derived myelination co-culture. Since the culture was derived from embryonic rat CNS tissue that contains primarily neural stem cells, our first attempt was to determine the cell phenotypes after neurons and glial cells differentiated. At DIV10, the typical culture contains 38.5% of NeuN+ neurons, 28.3% of Olig2+ OL lineage cells, 10% of Glial fibrillary acidic protein (GFAP)+ astrocytes, and 10% of CD11b+ microglia/macrophage (Fig. 2A–D). In general, neurons were usually found clustered together, and sent their neurites to the areas with a high density of OLs.