Figure 6.

The corpus callosum is thinner and the total number of oligodendrocytes is reduced in WAVE1−/−. A, CC1, a marker for mature oligodendrocytes, was immunostained with coronal sections of P21 mouse brain. B, Twenty-micrometer-thick coronal sections of P20 mouse brain were stained with a specific marker of pan-oligodendrocytes, Olig2, and detected by the ABC Elite kit with DAB substrate. Higher magnification is seen in the bottom panel. Fewer CC1+ cells and Olig2+ cells are obvious in corpus callosum (CC) of WAVE1−/− compared with WT controls. C, The number of Olig2+ cells was quantified within the designated callosal region in black line with two consecutive sections. Although the number of Olg2+ in CC is reduced (B), the density per square millimeter of Olig2+ cells is slightly increased in most areas except the corpus callosum, in which the cell density is virtually identical to WT. Interestingly, Olig2+ cells per square millimeter of cortex in WAVE1−/− were higher than WT by ∼53%. Error bars indicate SEM. ∗p < 0.05 (n = 6) and ∗∗p < 0.001 [n = 6 for CC and n = 4 for cortex (CTX), striatum (ST), septum (SEP)] by ANOVA. Scale bar, 10 μm. Arrows in A and B indicate inter-hemispheric fissure of the coronal section.