We JNK IN8 compared first the myelination between spinal cord and cortex-derived cultures using the manual counting approach. Our data revealed that no significant difference between these two cultures at this relatively early stage of myelination (Fig. 7A). Because of the extensive myelin formation in the culture after DIV26,

such manual counting was almost impossible. Thus, at DIV40 Inhibitors,research,lifescience,medical or later, myelination was quantified using ImageJ software in order to calculate the percentage of area occupied by MBP-immunostained myelin segments to the total area of the image. An additional advantage of this software program is that it allows us to eliminate the positive signals from OL cell bodies, since they are not part of the myelin structures (illustrated in Fig. Inhibitors,research,lifescience,medical 7C, D, and E). With this approach, a more accurate comparison can be made at different DIVs, and our data suggest that myelination appears to reach its threshold around DIV40 (Fig. 7B). Figure 7 Quantification of myelination. At DIV26, the number of myelin segments was manually counted and further compared between cortex derived cultures and spinal cord-derived Inhibitors,research,lifescience,medical cultures, and no significant difference was found between these two cultures (A). … Reproducibility of the co-culture model We have performed ten spinal cord and four cortex-derived cell culture (with T3 supplement) preparations. In all these cultures, myelin formation

(MBP/pNF double-labeled fibers) has been detected. However, although no difference in myelination at an earlier time-point (i.e., DIV26) was observed between these two tissue-specific cultures, the spinal cord-derived Inhibitors,research,lifescience,medical cultures produced more robust myelination at late stages (i.e., DIV40)

with better consistency (smaller variation across different preparations). More specifically, the myelin index at DIV40 was 11.5 ± 1.7 (mean ± SD) with a coefficient of variation at 14.8% for the spinal cord derived culture, compared to 8.1 ± 2.1 and 25.9% for the cortex-derived culture (P < 0.05). Proinflammatory Inhibitors,research,lifescience,medical cytokines induce myelin malformation After we established the feasibility and reproducibility of the new co-culture models, our next approach was to validate this new model for mechanistic studies. Our data revealed that myelination in the spinal cord-derived culture was significantly impaired by exposure to both TNFα and IL-1β, with IL-1β-treated cultures appearing more these severely affected than TNFα treatment (Fig. 8). In addition to the reduced number of myelin segments, MBP immunoreactive profiles were often found to be dispersed randomly around OL cell bodies in TNFα-treated cultures (arrow heads in Fig. 8B). In contrast, increased numbers of mature MBP+ OLs were often noted in IL-1β-treated cultures (arrows in Fig. 8C). These morphological changes of mature OLs in cytokine-treated cultures were not typically observed in the control (Fig. 8A).