(A–D) Representative images of microglial morphology traced with NeuronJ of ImageJ from the striatum of WT brain (A), striatum of R6/2 brain (B), striatum of WT brain treated with metformin (C), and striatum of R6/2 brain treated with metformin (D). Note that microglial cells from untreated R6/2 mice display shorter processes and diminished ramification of processes (B), whereas microglia from metformin-treated R6/2 mice show longer and highly ramified processes (D). Scale bars: 10 μm. (E) Quantification of average area occupied by individual microglia (in μm²) in the striatum of WT and R6/2 mice treated with metformin or vehicle. (F) Quantification of total process length by individual microglia (in μm) in striatum of WT and R6/2 mice treated with metformin or vehicle; n = 3. (G) Quantification of number of nodes in individual microglia in striatum of WT and R6/2 mice treated with metformin or vehicle. (H) Quantification of number of endings in individual microglia in the striatum of WT and R6/2 mice treated with metformin or vehicle (10–14 microglial cells per animal, n = 3 animals per group). Data are represented as mean ± SEM. Individual data points in the graphs represent an independent biological sample. Data were analyzed by 2-way ANOVA followed by Tukey’s test. *P < 0.05; **P < 0.01; ***P < 0.001.