Expression Profile Of Vimentin And GFAP In Central Nervous System Of New-born, Adult And Aged Rats

Objective To investigate the expression profile of Vimentin (Vim) and glial fibrillary acidic protein (GFAP), two main intermediate filament proteins in rat's central nervous system at different ages.Methods Twenty-four healthy SD rats were divided into three groups:newborn groups (7 days old, n=8), adult groups(5 months old, n =8) and aged groups (24 months old, n=8). Anesthetized with 10% chloral hydrate solution(400mg/kg)by intraperitoneal injection, rats were perfused with normal saline and 4% paraformaldehyde in order. Then the brain tissue and spinal cord were removed for post fixation(24 hours) and dipped into 15%,30%sucrose, OCT compounds embedding. Serial cryosections at the hippocampus, dentate gyrus and spinal cord L5 segment of the different ages were cut 25μm thick. The expression of Vim and GFAP were detected by double immunofluorescence with special antibodies against Vim and GFAP.Results (1) In all groups, there was expression of Vim, in the hippocampal formation, cerebral cortex and spinal cord, but it was highest in newborn rats, Vim mainly expressed in neuron-like cells. In adult and aged rats the Vim mainly localizeded at cell bodies. (2) In all groups, there was expression of GFAP, in the hippocampus, cerebral cortex and spinal cord, but it was highest in aged rats, GFAP mainly expressed in astrocytes. (3) In third ventricle of cerebrum, the expression of Vim was observed in all groups. However Vim positive neuron-like cells were detected in newborn rats. There was no significant difference in GFAP expression between adult and aged group. (4)The co-expression of Vim and GFAP were found in the cerebral cortex and hippocampus of newborn rat, while this co-expression occurred in the third ventricle can always be seen in all groups.Coclusion Our data for the first time demonstrated the expression profile of Vim and GFAP, two main IFs in rat's central nervous system at different ages. In the hippocampal formation, cerebral cortex and spinal cord, expression of Vim was down-regulated as age increased, whereas expression of GFAP was up-regulated during development and aging. In third ventricle of cerebrum, there was no obvious change in all groups, Vim was mainly expressed in neuron-like cells, but GFAP mainly in astrocytes. In some regions, co-expressin of Vim and GFAP was observed. The above result suggest that Vim and GFAP this two IFs have related to the CNS development and aging, This data may serve as a spring-board for further study of the role of Vim and GFAP during development, maturatioin and aging of central nervous system.