Abstract
The process of aging is linked to oxidative stress, microglial activation, and proinflammatory factors, which are known to decrease cell proliferation and limit neuroplasticity. These factors may lead the transition from normal aging to more severe cognitive dysfunction associated with neurodegenerative diseases. We have shown that natural compounds such as polyphenols from blueberry and green tea and amino acids like carnosine are high in antioxidant and antiinflammatory activity that decreases the damaging effects of reactive oxygen species (ROS), in the blood, brain, and other tissues of the body. Furthermore, we have shown that the combination of these nutrients (called NT-020) creates a synergistic effect that promotes the proliferation of stem cells in vitro and in vivo. In the current study, we examined the effects of NT-020 on neurogenesis and performance on a Morris water maze (MWM). Aged (20-month-old) male Fischer 344 rats were treated with 135.0 mg/kg per day (n = 13) of NT-020. Young (3-month-old) (n = 10) and aged (20-month-old) (n = 13) control male Fischer 344 rats were treated with water by oral gavage. All groups were treated for a period of 4 weeks. Although there was no difference in performance in the MWM when comparing all aged rats, when the data for aged impaired rats were compared, there was a significant difference between groups on the last day of training with the treatment group performing better than controls. Using the cell cycle-regulating protein (Ki67), doublecortin (DCX), and OX6 antibody markers, cell proliferation, neurogenesis, and microglial activation were estimated in the dentate gyrus (DG) of young and aged animals. Cell proliferation was also examined in the subventricular zone (SVZ). A decreased number of OX6 MHC II-positive cells, increased neurogenesis, and increased number of proliferating cells were found in rats treated with NT-020 in comparison with aged control rats. In sum, NT-020 may promote health, proliferation, and maintenance of neurons in the age animals and exert antiinflammatory actions that promote function in the aged stem cell niche.