Da Buyuanjian Combined with Exercise Improves Learning Memory of AD Rats by Modulating PI3K/Akt/GSK-3β Signaling Pathway / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo investigate the effects of 4 weeks of aerobic exercise combined with traditional Chinese medicine （TCM） on the regulation of phosphatidylinositol 3-kinase （PI3K）/protein kinase B （Akt）/glycogen synthase kinase-3β （GSK-3β） signaling pathway and related apoptotic proteins in AD rats， and to explore its mechanism of action in improving cognitive function of AD rats. MethodFifty male SD rats were randomly divided into Sham group， exercise （EX） group， Alzheimer's disease （AD） group （model）， TCM group （Dabuyuan Jian）， and EX+TCM group， 10 in each group. Aβ25-35 oligomer solution was injected into the hippocampal region to establish the AD rat model， and the EX group underwent 6 days/week of running table training. The TCM group was given Dabuyuan Jian （5.36 g∙kg-1） by gavage， and the EX+TCM group received running table training combined with intragastric administration of Dabuyuan Jian. An equal volume of purified water was given to the Sham， AD， and EX groups by gavage. The rats' learning memory was evaluated by Morris water maze. The morphological changes and ultrastructural changes of hippocampal neurons were observed by hematoxylin-eosin （HE） staining and transmission electron microscopy， respectively. Western blot was performed to detect the protein expression levels of Akt， p-Akt， GSK-3β， p-GSK-3β， β-catenin， Bcl-2， Bax， and cleaved Caspase-3 in the hippocampus of rats. ResultCompared with the Sham group， the AD group showed an increase in escape latency and total swimming distance， and a decrease in the residence time in the target quadrant （P<0.01）， with loose and disorganized arrangement of hippocampal pyramidal cells， a decrease in density， myelin-like changes in hippocampal ultrastructure， and a blurring of mitochondrial swelling. In addition， the expression of Bcl-2， p-Akt， p-GSK-3β and β-catenin was down-regulated （P<0.05， P<0.01） while the expression of cleaved Caspase-3 was up-regulated （P<0.05）. Compared with the conditions in the AD group， the escape latency and swimming distance were reduced in the EX， TCM， and EX+TCM groups， while the residence time in the target quadrant was increased （P<0.05，P<0.01）， with regularly arranged pyramidal cells， elevated number of cells， and reduced myelin-like changes and improved mitochondrial swelling as seen by transmission electron microscopy. Moreover， the expression of Bcl-2， p-Akt and p-GSK-3β was up-regulated， while the expression of cleaved Caspase-3 was down-regulated（P<0.05，P<0.01）. The EX+TCM group had increased level of β-catenin while the EX and TCM groups were not statistically significant compared with the AD group. Compared with the EX+TCM group， the EX and TCM groups had increased escape latency and swimming distance and decreased residence time in the target quadrant（P<0.05，P<0.01）， with loosely arranged pyramidal cells and reduced synaptic integrity under transmission electron microscopy（P<0.01）. Furthermore， the levels of Bcl-2， p-Akt， p-GSK-3β and β-catenin were lowered （P<0.05，P<0.01）while the level of cleaved Caspase-3 was elevated（P<0.05）. ConclusionAerobic exercise combined with Dabuyuan Jian could improve the cognitive dysfunction of AD rats， and the mechanism might be related to the elevated expression of key proteins in the PI3K/Akt/GSK-3β signaling pathway. The combined use was better than the use of exercise or drugs alone.