Effect of Hei Xiaoyaosan on Neuroinflammation in AD Model Rats： Based on Wnt/β-catenin Signaling Pathway / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo explore whether Hei Xiaoyaosan can inhibit the inflammatory response in the hippocampi of Alzheimer's disease （AD） rats by regulating and activating the Wnt/β-catenin signaling pathway to improve the cognitive and memory dysfunction. MethodAmong the 90 male Wistar rats， 12 were randomly selected as the blank group （normal saline） and 12 as the sham operation group （normal saline）. For the remainder， amyloid β-protein42 （Aβ42） was injected in the left and right hippocampus to induce AD， and then the AD rats were randomized into model group， low-， medium-， and high-dose Hei Xiaoyaosan groups （corresponding doses of Hei Xiaoyaosan， ig）， and donepezil group （donepezil hydrochloride，ig）， with 12 in each group. The administration lasted 42 days. The pathological changes of hippocampal CA1 region was observed based on Nissl staining. The escape latency on the 1st to 5th day in Morris water maze was recorded and the spatial memory on the 6th day was tested. Enzyme-linked immunosorbent assay （ELISA） was employed to detect the expression of interleukin （IL）-6， IL-10， and tumor necrosis factor-α （TNF-α） in rat hippocampus and serum， Western blotting to examine the protein expression of glycogen synthase kinase-3β （GSK-3β）， β-catenin， and peroxisome proliferator-activated receptor gamma （PPARγ）， and real-time polymerase chain reaction （Real-time PCR） to determine the mRNA expression of rat GSK-3β， β-catenin， and PPARγ. ResultCompared with the blank group， the number of neurons in the hippocampal CA1 area of model group was significantly reduced， the arrangement was uneven， the cell body was damaged more obviously， and the Neisser body was unclear. The treatment group was significantly prolonged （P<0.01）， and the number of crossing stations was significantly reduced （P<0.01）， the levels of IL-10 in serum and hippocampus of rats in the model group were significantly decreased， while the levels of IL-6 and TNF-α were significantly increased （P<0.01）， the GSK-3β protein and mRNA in the model group were significantly increased， and the protein expressions of β-catenin and PPARγ were significantly decreased （P<0.01）， and the difference was more obvious. The number of neurons in the donepezil group was more distributed， neatly arranged， the structure was intact， and the Nissl bodies were clear and definite， the escape latency on the 3rd to 5th days in middle and high dose groups of Hei Xiaoyaosan and the donepezil group was significantly shortened （P<0.01）， the number of crossing platforms increased significantly （P<0.01）， the expression levels of IL-10 in the rat hippocampus and serum were significantly increased， while IL-6 and TNF-α were significantly decreased （P<0.01）， GSK-3β in the rat hippocampus was significantly increased. The expressions of GSK-3β protein and mRNA were significantly decreased， while the expression levels of β-catenin and PPARγ protein and mRNA were significantly increased （P<0.01）. There was no significant difference in each index between the donepezil hydrochloride group and the high-dose Hei Xiaoyaosan group. ConclusionHei Xiaoyaosan can inhibit the inflammatory response in the hippocampus of AD rats by regulating the Wnt/β-catenin signaling pathway， thereby alleviating the cognitive and memory impairment of AD rats.