Expression and Changes of Hyperoxidized Peroxiredoxins in Non-Pyramidal and Polymorphic Cells in the Gerbil Hippocampus During Normal Aging

초록

Oxidative stress is one of predisposing factors to age-related neurodegeneration in the brain. In particular, thiol-containing groups are susceptible to oxidative stress, which induces the formation of the disulfide bond and/or hyperoxidized form of thiol-containing proteins. We observed the protein thiol levels in the hippocampal homogenates and also investigated changes in hyperoxidized form of peroxiredoxin (Prx-SO3) immunoreactivity and proteins levels in the gerbil hippocampal subregions during normal aging. Levels of total thiol, non-protein thiol, and protein thiol were decreased in the hippocampal homogenates with age. At post-natal month 1 (PM 1), pyramidal and non-pyramidal cells in the hippocampal CA1 region (CA1) showed Prx-SO3 immunoreactivity. Prx-SO3 immunoreactivity in the cells was decreased by PM 12, thereafter, Prx-SO3 immunoreactivity in the cells increased again with age. In the CA2/3, Prx-SO3 immunoreactivity in pyramidal cells was not significantly changed; however, the immunoreactivity in pyramidal cells was very low at PM 12. Prx-SO3 immunoreactivity in the dentate gyrus (DG) was distinctly changed during aging. At PM 1, Prx-SO3 immunoreactivity in granule and polymorphic cells was weak and strong, respectively. The immunoreactivity in the neurons was decreased with age, not shown in any neurons at PM 12. Thereafter, Prx-SO3 immunoreactivity increased again with age. In addition, Prx-SO3 protein level in the hippocampus was lowest at PM 12. These results suggest that thiol-containing proteins are changed during aging and Prx-SO3 immunoreactivity was different according to cells in the hippocampal subregion during aging.

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