A histopathologic study of the brains from 96 mice, ranging in age fro
m 3 to 57 months in age, documents an age-associated increase in hyper
trophic astrocytes in white matter. This report of gliosis is distinct
from previously reported proliferation of glial cells in the grey mat
ter. Four genotypes, CBA/HT6J, C57BL/6J, B6CBAT6F1J, and B6C3F1 were p
ositive for this age-related lesion. Most very old mice utilized in th
is study were calorically restricted, a dietary manipulation long know
n to result in increased longevity in rodents. Caloric restriction app
ears to delay the age associated increase of this lesion. Immunoperoxi
dase staining for the astrocycte-specific glial fibrillary acidic prot
ein (GFAP) confirmed the progressive increase in the density of staina
ble astrocytes with increase in age. GFAP staining of white matter inc
reased in both diet groups with age. These findings present an interes
ting model for the study of aberrant cellular activity and perhaps neu
rodegeneration, modulated by caloric restriction.