Figure 5.

IFNγ increases the process length of gmOPCs and wmOPCs and reduces the number of branch points in wmOPCs. Oligodendrocyte progenitor cells (OPCs) isolated from the cortex (gmOPCs) and non-cortex (wmOPCs) of neonatal rat forebrains were left untreated or treated with 10 ng/ml TNFα, 500 U/ml IFNγ, or a combination of TNFα and IFNγ for 48 hours in the presence of PDGF-AA and FGF-2. (a) Cell cytotoxicity as measured with an LDH assay (n = 4). (b) Cell viability as measured with MTT reduction (n = 4). Note that IFNγ treatment reduces the MTT reduction in both gmOPCs and wmOPCs compared to their respective untreated control. (c–e) OPCs stained with the OPC cell surface marker antibody A2B5. Representative images are shown (e). (c,d) Analysis of the morphology of gmOPCs and wmOPCs of the same batch. The process length (c, n = 3) and the number of branch points (d, n = 3) are shown. Note that IFNγ increases the process length of gmOPCs and wmOPCs (c) and reduces the number of branch points in wmOPCs, but not gmOPCs (d). When IFNγ is combined with TNFα the number of branch points is decreased in either OPC. Bars represent mean relative to their respective untreated control, which was set at 1 for each independent experiment (horizontal line). Grey bars represent gmOPCs, white bars represent wmOPCs. Error bars show the standard error of the mean. Statistical analyses were performed using column statistics with a one-sample t-test (*p < 0.05, **p < 0.01,***p < 0.001) to test for differences between treatments and their respective control and a one-way ANOVA with a Šidák post-test was used to test whether the response to TNFα, IFNγ and TNFα and IFNγ combined differed between gmOPCs and wmOPCs (not significant). Scale bar is 50 µm.