Fig. 6

A53T-aSYN overexpression leads to a pronounced reactive micro- and astrogliosis in the LC-region. a Representative images of the LC region of Luc (left column) or A53T-aSYN (right column) injected animals stained for TH (green), IbA1 (gray) and GFAP (red) display a marked increase of micro- and astroglia over time in A53T-aSYN overexpressing mice. Quantification of GFAP (b) and IbA1 (c) signal intensity revealed a progressive increase of astro- and microglia signal in A53T-aSYN injected animals (red boxes) compared to Luc control (black boxes). Values (mean ± min/max) are expressed as the signal intensity ratio of the injected side compared to the non-injected side. n = 6 animals per time point and group. Two-way ANOVA analysis followed by Tukey’s post-hoc test, *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. d Reconstructed high magnification confocal images of the LC region showing physical contacts between TH-positive (green) LC cells and IbA1-positive micro- (gray) and GFAP-positive astroglia (red) after 3 weeks of A53T-aSYN overexpression (lower right). Engulfment (arrow) of TH-positive neurons by glial cells was only observed in A53T-aSYN expressing animals and not in Luc control mice (upper row). e Direct physical contacts were also observed between micro- and astroglia (arrow). f, g Correlating TH cell loss with the microglia intensity values indicates a strong association between increase of microglia and severity of TH cell loss in A53T-aSYN overexpressing animals (r = 0.80, p < 0.05), whereas there was no correlation in Luc expressing animals (r = 0.09, p > 0.05). Pearson’s correlation coefficient with 95% confidence interval. Scale bars 100 μm in a, 25 μm in d and e