Fig. 5

Culture and cryogenic storage of human primary microglia. a-b Representative phase contrast images of WM microglia under basal culture conditions showing cells with a slightly ramified morphology cultured for 5 days and 10 days respectively (x200). c Phase contrast image (x100) of WM microglia incubated with pHrodo-labeled myelin for 48 h at 5 DIV. Superimposed red fluorescence signal shows labeled myelin in phagosomes. d Gene expression analysis of microglia after 4 DIV compared to acutely lysed cells, expressed as fold change from acute (Mann-Whitney tests, n = 4). e Correlation plot of RNA yield with starting number of microglia (Spearman correlation). f Linked scatterplot showing the recovery of viable microglia after cryogenic storage. Cells from both WM and GM were used (n = 15). g RNA integrity of samples from cryogenically stored microglia is not significantly decreased compared to acutely lysed samples (Wilcoxon matched-pairs test). h Fluorescence geometric mean of CD45 and CD11b expression of WM microglia before and after cryogenic storage shows that CD45, but not CD11b expression is increased due to freezing (Wilcoxon matched-pairs test). *p value <0.05