Fig. 4.

Mutant huntingtin (mHtt) expression levels in GABAergic interneurons in the striatum of 12-week-old R6/2 mice. R6/2 striatal tissue sections dual-labeled for mHtt (green, left column; scale bar: 50 µm) and parvalbumin (Parv; A), calretinin (B) or neuropeptide Y (NPY; C) interneurons (red, middle column). Small inserts on the right are magnified images of mHtt expression in the soma of each interneuron subtype as identified by a thin arrow in the parent image (scale bar: 5 µm). (C3) Magnified image of an NPY-labeled neurite (C2) containing a mHtt aggregate (C1, scale bar: 10 µm). (D) sq-IHC analysis of the expression level of mHtt within each subtype of striatal interneuron normalized to calretinin levels expressing levels close to background levels (n = 5 R6/2 mice, ***P < 0.001 compared with calretinin and NPY subtypes). All values are expressed as mean ± SEM normalized to mHtt mean intensity in calretinin interneurons, and analysed by one-way anova with Tukey’s post hoc analysis.