Age-related changes of glial fibrillary acidic protein immunoreactive astrocytes in the rat cerebellar cortex

Age-related changes of glial fibrillary acidic protein (GFAP) immunoreactiv ity were investigated in the cerebellar cortex of young (3 months), adult ( 12 months) and old (24 months) rats using immunohistochemical techniques as sociated with image analysis. In young rats, cell bodies of GFAP-immunoreac tive astrocytes were found in the white matter and in the granular layer of cerebellar cortex. Radially-oriented branches of astrocytes which are site d in the granular layer were also observed in the molecular layer. The numb er of GFAP-immunoreactivity astrocytes of white matter was decreased in adu lt and old rats in comparison with young cohorts, whereas their size increa sed progressively from 3 to 24 months old. The number and the size of GFAP- immunoreactive astrocytes of the granular layer was similar in young and ad ult rats. An increased number and size of GFAP-immunoreactive astrocytes wa s noticeable in old rats in comparison with younger cohorts. The number of radially oriented branches of the molecular layer was the same in the three age groups investigated. The above results indicate that GFAP-immunoreacti ve astrocytes of rat cerebellar cortex undergo age-related changes. The not homogeneous sensitivity to aging of cerebellar astrocytes suggests that ev aluation of changes of different cell populations of cerebellar cortex shou ld represent an important step of research on aging cerebellum. (C) 1999 El sevier Science Ireland Ltd. All rights reserved.