Fig. 2

Immunohistochemical analysis of young and aged degus. H&E stain revealed normal age-related changes but no signs for lesions, neurodegeneration, or displacement in young (1-year-old, a) and aged (5-years-old, b) animals. Density of cortical neurons (NeuN-satin) remained virtually unchanged in aged degus (d), compared to young (c). IBA1-stain (e, f) revealed homologues populations of resting microglia cells (young, e; aged, f)). GFAP Immunoreactivity was slightly decreased in aged animals (h), but spatial distribution (layer 1, surrounding vessels) was similar (young: g; aged: h). Campbell-Switzer stain unveiled neither extracellular plaques nor tangles (i, j). Thioflavin T likewise indicated no amyloid plaques (young, k; aged, l). Semi-automatically determination of neurons (m) as well as microglial cells (n) and astrocytes (o) in cortices revealed no significant changes in aged animals. Scale bars = 100 μm. Data is presented as mean ± SEM (n ≥ 4)