Fig. 4

Intrathecal miR-124-5p and miR-92a-1-5p trigger changes in dendrite and axon structure, synaptophysin expression, and cell viability in the mouse cerebral cortex via TLR7. (a) Representative images of brain cortical sections from C57BL/6 (WT) or Tlr7^−/− mice. Each mouse received intrathecal injection of either 10 µg miR-92a-1-5p, miR-124-5p, or Mut.oligo. After 3 d, mice were sacrificed, and brain sections were immunolabeled with MAP-2, Neurofilament, and Synaptophysin antibodies. Quantification of (b) dendritic length, (c) dendrite degeneration index, (d) axonal length, (e) axonal degeneration index, and (f) synaptophysin expression in the brain sections described above. Violin plot: solid line indicates median, horizontal dotted line indicates the median of the WT control group (n = 4–6). *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001, compared to respective control, Kruskal-Wallis test with Dunn’s post-hoc analysis. ^##P < 0.01 compared to corresponding Tlr7^−/− group, Mann-Whitney test. (g) Representative images of the brain sections described above, immunolabeled with NeuN antibody. (h) Quantification of NeuN⁺ cells in brain sections described above. Bars represent mean ± SEM (n = 4–6 per indicated condition), unpaired t-test. n.s., not significant. Scale bar, 50 μm