Fig. 4.

Aging increases the frequency of neurons with a senescence-like phenotype. (A) Frequencies of Purkinje neurons positive for the indicated marker (in %) at the indicated ages as measured by immunofluorescence and immunohistochemistry. (B) Purkinje neuron autofluorescence intensity (in arbitrary units) at the indicated ages. (C) Frequencies of cortical neurons positive for the indicated marker (in %). (D) Cortical neuron autofluorescence intensity (in arbitrary units). All data are mean ± SEM, from at least three animals per age group. * and # indicate significant differences to 4 and 8 months old animals, respectively (anova with post hoc Tukey, P < 0.05). (E) Frequencies of gut neurons positive for γH2A.X (in % of all neurons per ganglion) and (F) intensity of neuronal DHR-123 staining (arbitrary units) in young (5 months) and old (22–24 months) mice. Data are from > 15 ganglia from 2 or 3 mice per age group.*P < 0.01, t-test). (G) Frequencies of Purkinje neurons positive for the indicated marker (in %) and (H) autofluorescence intensity (in arbitrary units) in 17 months old ad libitum fed (AL) animals and in mice kept under dietary restriction (DR) from 14 to 17 months of age. Data are mean ± SEM, from three animals per age group. * indicate significant differences (P < 0.05, t-test).