AGE-RELATED GLIOSIS IN THE WHITE MATTER OF MICE

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.