Long-term oral administration of curcumin is effective in preventing short-term memory deterioration and prolonging lifespan in a mouse model of Alzheimer’s disease

Curcumin (Curc) has been shown to have the potential to ameliorate or prevent the development of Alzheimer's disease (AD). However, most of them are in vitro and in vivo short-term studies. This study was conducted to investigate whether long-term, low-dose dietary Curc intake in mouse of AD might suppress short-term memory retention, amyloid-beta (Aβ) deposition and tau phosphorylation, delaying the onset of AD and prolonging the lifespan of the animals. Short-term memory was examined by the Y-maze method after 6 months old. Immunohistochemical analysis was performed at 10 months old to determine changes in Aβ deposition, tau phosphorylation, and glial cell number in brain tissue. Furthermore, we investigated the survival rate for 12 months old and evaluated the AD prevention effect. The alternation rates of short-time memory in the wild type and AD mice were 56.2% and 25.9%, respectively. These rates in the experimental groups (0.02% and 0.5% Curc) were in the range of 44.4–45.7%. The area of Aβ42 deposition in AD mice was approximately 25,000 µm², while the experimental groups had a significantly reduced area of 5000–10,000 µm². Survival rate was 34% in the AD control group, 100% in the 0.02% Curc, and 83% in the 0.5% Curc group, significantly longer in the Curc groups than the AD control group. This study demonstrates that long-term intake of low concentrations of Curc may act on the tau- phosphorylation, suppress brain inflammation, delay the onset of AD, and prolong the lifespan of the mouse.