Comparison of Alpha-Synuclein Immunoreactivity in the Hippocampus Between the Adult and Aged Beagle Dogs

초록

Alpha-synuclein (alpha-syn), as a neuroprotein, is expressed in neural tissue, and it is related to a synaptic transmission and neuronal plasticity. In this study, we compared the distribution and immunoreactivity of alpha-syn and related gliosis in hippocampus between young adult (2-3 years) and aged (10-12 years) beagle dogs. In both groups, alpha-syn immunoreactivity was detected in neuropil of all the hippocampal sub-regions, but not in neuronal somata. In the aged hippocampus, alpha-syn immunoreactivity was apparently increased in mossy fibers compared to that in the adult dog. In addition, alpha-syn protein level was markedly increased in the aged hippocampus. On the other hand, GFAP and Iba-1 immunoreactivity in astrocytes and microglia, respectively, were increased in all the hippocampal sub-regions of the aged group compared to that in the adult group: especially, their immunoreactivity was apparently increased around mossy fibers. In addition, in this study, we could not find any expression of alpha-syn in astrocytes and microglia. These results indicate that alpha-syn immunoreactivity apparently increases in the aged hippocampus and that GFAP and Iba-1 immunoreactivity are also apparently increased at the regions with increased alpha-syn immunoreactivity. This increase in alpha-syn expression might be a feature of normal aging.

키워드