Comparison of density and morphology of neuroblasts in the dentate gyrus among variously aged dogs, German shepherds

Abstract

Neural progenitor cells in the dentate subgranular zone (SGZ) produce new cells all through life via proliferation. We observed differences in neuroblasts using doublecortin (DCX, a marker of neuronal differentiation) in the SGZ in variously aged dogs (German shepherds). In the 1-year-old group, DCX-immunoreactive (+) cells were abundantly observed in the SGZ: These cells had processes extending into the molecular layer. In the 3-year-old group, DCX+ cells were decreased by 53.0% compared to that in the 1-year-old group, and DCX+ processes were also markedly decreased. In the 6 and 8-year-old groups, DCX+ cells were decreased by 34.3% and 62.9% vs. the pre-aged group. In the 8-year-old group, DCX+ cells were decreased by 86.4% compared to that in the 1-year-old group. In the 12-year-old group, DCX+ cells and processes were nearly disappeared. This suggests that DCX+ cells processes significantly decreased at 3 years in the SGZ of the German shepherd.