Figure 5.

MSC-EVs improve oligodendrocyte maturation and myelination. Oligodendrocyte maturation and myelination was investigated in the white matter (external capsule) and the striatum via immunohistochemistry in co-staining for the pan-oligodendrocyte marker Olig2 (red, A,B) and either O4, labeling immature oligodendrocyte precursor cells (green, A) or CC1, labeling mature oligodendrocytes (green, B). Myelination was assessed by co-staining against MBP (violet, B,C). Representative images are obtained from the external capsule. Low magnification images (scale bar: 40 μm) reveal maximal intensity projections of 10 μm z-stacks (plane distance 2 μm). To demonstrate morphology, high magnification images (scale bar: 10 μm) were acquired at a single plane in the white square, depicted in low magnification images. The percentage of double positive cells from total oligodendrocytes was quantified (A,B). Myelination was quantified by measurement of MBP⁺ areas (C). Immunohistochemistry analyses were confirmed by mRNA expression analyses of CC1, CNPase and MBP in brain tissues (160 μm thickness) obtained from the striatal level (0.5 mm to 0 mm from bregma). Beta-2-microglobulin served as housekeeping gene and fold change values compared to vehicle-treated control animals were calculated (D) *p < 0.05, **p < 0.01, ***p < 0.001, n = 12/group.