The Vitamin A Derivative All-Trans Retinoic Acid Repairs Amyloid-β-Induced Double-Strand Breaks in Neural Cells and in the Murine Neocortex
RA repairs Aβ-induced DSBs in the neocortex of C57BL/6J mice. (a) Representative pictures of comets with various tail lengths of cortical cells originating from young (4 months; mice) or (b) aged (16 months; ) mice following 30 min RA (5 μM) and/or 30 min Aβ (20 μM) in vitro treatments. Ø = without treatment for 30 min; scale bar: 200 μm. (c) Box plots of mean comet tail lengths of 3 young (number of cells measured: ) and of (d) 3 aged mice (). Statistical analyses (ANOVA with Bonferroni correction) revealed significant differences in all 3 young mice (), whereas only 2 out of 3 () or 1 out of 3 aged mice () reached statistical significance; ns = not significant. (e) Immunofluorescent pictures of cortical cells of young mice stained with anti-βIII-tubulin to mark neurons, anti-GFAP to label astrocytes, and DAPI as a nuclear marker. A similar study war carried out with cortical cells of aged mice. (f) Proportions of neurons, astrocytes, and other cell types in the cortex of young () and of aged mice (). Number of cells analyzed for each mouse: . : comparison between neurons and astrocytes.