Histone deacetylase signaling plays a critical role in age-related decrease in adult neurogenesis

Aging is associated with a striking increase in the incidence of stroke and neurodegenerative diseases, both of which are major causes of disability among those age 70 years and older in the United States. Adult neural stem/progenitor cells (NSCs) hold great promise for brain repair due to their unique location within the central nervous system, which continues through the life span. However, neurogenesis is significantly declined with aging. Purpose: the underlying mechanisms remain largely unexplored. Methods: HDAC expression in the young adult and aged brain was determined by immunohistochemistry. And then the young adult and old rats are administrated with histone deacetylases (HDACs) inhibitor by intraperitoneally and then immunohistochemistry test was performed. Results: First, we found that HDACs I and II were expressed in the NSCs in the subventricular zone (SVZ) and the subgranular zone (SGZ) of hippocampus in normal adult rat brain using immunohistochemistry. Second, the expression level of HDACs in the SVZ and SGZ was significantly altered in aged brain compared with young adult brain. In addition, the number of NSCs in aged brain was significantly increased after administration of HDAC inhibitor. Conclusion: Our data suggest that HDAC signaling may be an important factor in determining the neurogenesis in aged brain.