Cell-based phenotypic assays using OL1 cells.

Double-immunofluorescence labeling of OL1 cells (upper). OL1 cells were cultured with differentiation medium containing thyroid hormones on dishes coated with poly-L-ornithine with/without aggrecan at the indicated concentrations. After 10 days, cells were fixed with formalin and stained with anti-NG2 proteoglycan (OPCs; red) and anti-MBP (mature oligodendrocytes; green) antibodies, in conjunction with the 4′,6-diamidino-2-phenylindole (DAPI) labeling of nuclei (blue). Scale bars, 100 μm. Scatter plots show the ratio of MBP-positive cells to NG2-positive cells (lower left), and total DAPI-positive cell numbers relative to the average of the vehicle control (lower right). Each circle corresponds to an independent cell culture (n = 5 each). *, p < 0.05 and **, p < 0.01, significant difference between the indicated groups (analysis of variance with Bonferroni’s post-hoc tests).