Interplay of curcumin and its liver metabolism on the level of Aβ in the brain of APP swe /PS1 dE9 mice before AD onset

Background An increasing number of studies have shown that Alzheimer’s disease (AD) is a systemic disease characterized by brain dysfunction. In this study, we aimed to investigate the effects of curcumin on the liver, an important metabolic organ, and on the brain in APP swe /PS1 dE9 (APP/PS1) mice, and the interaction between these effects. Methods Curcumin was administered to 5-month-old APP/PS1 transgenic mice for 7 consecutive days using the intragastric (ig) and intracerebroventricular (icv) administration routes, respectively. The object recognition test (ORT) and open field test (OFT) were conducted to evaluate long-term recognition memory and anxiety after curcumin administration. Levels of β-amyloid (Aβ), Aβ 42, and interleukin-1β (IL-1β) in the brain and liver were measured. Results In the ig group, curcumin ameliorated anxiety-like behavior and suppressed the level of Aβ 42 in the liver and the total Aβ in the brain. In the icv group, curcumin treatment affected the distribution of Aβ 42 and IL-1β in the brain compared to the liver. There was a significant treatment–region interaction in Aβ 42 level for the icv group ( F (1, 24) = 17.7, p < 0.001), but no interaction effect for the ig group. Conclusion Our findings show that curcumin administration before Aβ deposition shows promise for preventing AD, and further that curcumin may play an important role in the clearance of Aβ 42 from the brain to the peripheral circulation.