(D) Neuronal cell death was evaluated in the cerebellum (Calbindin immunostaining) and in different layers of cortex (NeuN immunostaining of frontal cortex) of 10 months-old mice belonging to each experimental group of mice. Number of cells was quantified from 20 different images (taken from 5 mice for each group) and expressed as % of WT. Values are means ± s.e.m. *P<0.05, **P<0.001 Student's t-test. Scale bar: 50 µm. 