SIRT2 Protein Expression in Normal and Aged Rat Brain

Oh, Chang Seok; Lee, Eunju; Lee, Young Soo; Shin, Dong Hoon

Abstract

BACKGROUND
Studies on surtuin2 (SIRT2) proteins, particularly those focusing on the nervous system, have not been intensively done. Furthermore, neither the types of neural cells involved nor the changes in SIRT2 expression in each type have been clearly elucidated. In the present study, we used morphological techniques such as the double immunohistochemical study to assess the changes in the expressions of SIRT2 proteins in the rat brain during the aging process.
METHODS
The immunohistochemical analyses employing anti-SIRT2, NeuN and GFAP antibodies were performed on 8-week and 24-month post-natal rat brains. Immunostained samples were observed under fluorescent microscopy.
RESULTS
In the hippocampus of the 8-week old rat brains, most of the SIRT2 immunoreactivities (IRs) were localized in the GFAP-positive astrocytes. Contrastingly, the 24-month old rat brains showed aging-related changes- the SIRT2 IRs were highly increased in the NeuN-positive neurons, unlike in the 8-week old brains, which only showed low SIRT2 IRs. In samples representing the same age, the increase of SIRT2 IRs in the astrocytes was not as remarkable as in the neurons.
CONCLUSION
Although previous studies have found increased SIRT2 in aged brains, they could not determine the type of neural cells responsible for such changes. Significantly, the data derived from the present study demonstrated that increased SIRT2 in aged brains was caused mainly by changes to the protein expression in neurons. Considering that SIRT2 is known to be related to the anti-aging process of cells, highly expressed SIRT2 in neurons might play a role in inhibiting the aging of the central nervous system.