ABSTRACT
Objective To study the in vivo expression patterns of caspase-3 in normally aged primate brain. Methods Fresh brain tissue was taken from 4-year-old and 20-year-old female rhesus monkeys,4 for each age group. In vivo distribution of caspase-3-positive cells and its protein levels in different brain regions were investigated by immunohistochemical and immunoblot means,respectively. Results In the frontal cortex,most neurons lacked detectable caspase-3 immunoreactivity,whereas low to moderate caspase-3 immunostaining was found mainly in pyramidal cells in CA1,CA3 and CA4 subdivisions of hippocampus. And in the cerebellum,a small number of Purkinje cells were strongly stained in their cytosol and dendrites,while their nuclei lacked staining. Age-related changes in caspase-3 expression pattern were not found. Immunostaining of motor cortex in aged monkeys localized strong caspase-3 immunoreactivity to a limited number of large pyramidal cells in layer V. Immunoblotting revealed the 32 000 caspase-3 progenitor in all three brain regions. There were no differences in caspase-3 expression levels as a function of either brain region or age of animals. Conclusions These results suggest that caspase-3 is constitutively expressed in matured primate brain and there is no significant age-related change in its expression.