Oolong Tea Extracts Alleviate Behavioral Abnormalities by Modulating Neuroinflammation in APP/PS1 Mouse Model of Alzheimer's Disease.

Alzheimer's disease (AD) is a common neurodegenerative disease; tea components have important neuroprotective effects. This article explores the effects and mechanisms of Qingxiang (Tgy-Q), Nongxiang (Tgy-N), and Chenxiang (Tgy-C) extracts on APP/PS1 AD model mice. Morris water maze and new object recognition experiments show that extracts can effectively enhance the cognitive ability of APP/PS1 mice. H&E staining, Nissl staining, and immunohistochemical staining show that extracts make nerve cell boundaries and nucleoli become clearer, relieve nucleus pyknosis, and effectively reduce Aβ1-40 and Aβ1-42 in the hippocampus and cortex. They also restore the morphology of microglia and astrocytes. In addition, extracts can balance the oxidative stress level in the brain of APP/PS1 mice by improving the antioxidant capacity. Western blot results show that extracts can reduce the expression of NF-κB p65, TNF-α, IL-1β, IL-6, COX-2, and iNOS in mouse brain, which demonstrates that extracts improves cognitive ability by alleviating inflammation. This article demonstrates for the first time that extracts can inhibit the excessive activation of the NF-κB p65 signaling pathway and improve the antioxidant capacity in the cerebral cortex and hippocampus, to improve the cognitive ability of APP/PS1 mice. Our results shed light into the beneficial of tea extracts on preventing and alleviating AD diseases.