Curcumin ameliorates lipid metabolic disorder and cognitive dysfunction via the ABCA1 transmembrane transport system in APP/PS1 double transgenic mice.

The disorder of lipid metabolism, especially cholesterol metabolism, can promote Alzheimer's Disease. Curcumin can ameliorate lipid metabolic disorder in the brain of Alzheimer's Disease patients, while the mechanism is not clear. APP/PS1 (APPswe/PSEN1dE9) double transgenic mice were divided into dementia, low-dose, and high-dose groups and then fed for six months with different dietary concentrations of curcumin. Morris water maze was used to evaluate the transgenic mice's special cognitive and memory ability in each group. In contrast, the cholesterol oxidase-colorimetric method was used to measure total serum cholesterol and high-density lipoprotein levels. Immunohistochemistry was used to evaluate the expression of liver X receptor-β, ATP binding cassette A1 and apolipoprotein A1 of the hippocampus and Aβ42 in the brains of transgenic mice. The mRNA and protein expression levels of liver X receptor-β, retinoid X receptor-α and ATP binding cassette A1 were evaluated using qRT-PCR and Western blotting, respectively. Curcumin improved the special cognitive and memory ability of transgenic Alzheimer's Disease Mice. The total serum cholesterol decreased in Alzheimer's Disease mice fed the curcumin diet, while the high-density lipoprotein increased. The curcumin diet was associated with reduced expression of Aβ and increased expression of liver X receptor-β, ATP binding cassette A1, and apolipoprotein A1 in the CA1 region of the hippocampus. The mRNA and protein levels of retinoid X receptor-α, liver X receptor-β, and ATP binding cassette A1 were higher in the brains of Alzheimer's Disease mice fed the curcumin diet. Our results point to the mechanism by which curcumin improves lipid metabolic disorders in Alzheimer's Disease via the ATP binding cassette A1 transmembrane transport system.