Fig. 1: Characterization of the Cx3cr1creER/+R26RConfetti/+ (Microfetti) mouse model for fate mapping of microglia in ischemic stroke.
a Scheme for the experimental design of fate mapping of microglia after 30-min middle cerebral artery occlusion (MCAo) in Microfetti mice. Created in BioRender. Göttert, R. (2025) https://BioRender.com/rhlc1w4. b Illustration of the imaged regions of interest in the lateral part of the ischemic and contralateral striatum. For each animal, three consecutive brain slices were imaged with four images per slice per hemisphere. Created in BioRender. Göttert, R. (2025) https://BioRender.com/pzkky3d. c Representative fluorescent image of Iba-1+ microglia (magenta) in the contralateral striatum showing ramified morphology. In addition, many cells express one of four fluorescent proteins: membrane-tagged CFP (mCFP, cyan), nuclear GFP (nGFP, green), cytoplasmic YFP (yellow), and cytoplasmic RFP (red). Scale bars: 100 µm and 30 µm in the magnified images. d Representative images from the time course analysis of the ischemic lateral striatum from each investigated time point: 2 days, 1, 2, 4, 8, and 12 weeks. After 1 week, there is a clear increase in the number of Confetti+ microglia, indicating microglial proliferation. In addition, the appearance of many clusters of cells expressing the same fluorescent marker and located close to each other suggests polyclonal proliferation dynamics. After 8 weeks, there is a clear decrease in the number of Confetti+ microglia, and large clones are less apparent. Lipofuscin autofluorescence signal is present at 8w and 12w time points. Scale bar: 100 µm. e Quantification of Confetti+ microglia in the ischemic and contralateral striatum showing the dynamics of microglial proliferation after 30-min MCAo. In contrast, the contralateral hemisphere displays a stable number of cells over the investigated period. Each dot represents one brain hemisphere from one mouse. Means ± s.e.m. are shown. Statistical analysis with two-way ANOVA, Šidák’s multiple comparisons test for contralateral vs. stroke comparisons, and Dunnett’s multiple comparisons test for time point comparisons. Number of animals N = 8 (2 d), 8 (1w), 7 (2w), 7 (4w), 7 (8w), 6 (12w).
