Rehabilitation Training Ameliorated Vascular Dementia By Regulating The Expression Of Hippocampal Amyloid-beta Peptide

Objective: To study the mechanism on rehabilitation training ameliorated learningand memory ability in vascular dementia rats by regulating the expression of hippoca-mpal amyloid-beta peptide.Methods: Allocating randomly45Sprague-Dawley(SD) rats to a rehabilition traininggroup(n=15), a model group(n=15) and a sham-operation group(n=15). The rats in theformer2groups were operated on to establish the experimental vascular dementiamodel by bilateral common carotid artery permanent ligation. The rehabilition traininggroup was given the training of balance beam and turning barrel for4weeks. The rats’Behavioral assessment were taken by Spontaneous activity experiments, Morris’s watermaze test, spontaneous alternation Y-Maze test and novel object recognition test at4weeks after operation. Hematoxylin-eosin staining was used to detect hippocampalmorphology change.Immunohistochemical staining was used to detect amyloid-betapeptide(Aβ), β-secretase(BACE), Insulin-degrading enzyme(IDE) expression inhippocampus.Results:1. Spontaneous activity detection results: Rats’ total activity time, centralarea activity time, the peripheral activity time, the level of activity distance, Centralarea activity distance, the peripheral activity distance had no significant differenceamong the model group, the rehabilitation group and the sham-operatiton group(p<0.05).2. Y-maze test: the model group rats’ correct alternation ratio in Y-Maze is lowerthan the sham-operation group rats’(p<0.05), and the rehabilitation group rats’alternate correct ratio in Y-Maze is higher than the model group rats’(p<0.05), therehabilition group rats’ correct alternation ratio in Y-Maze is lower than the sham-operation group rats’(p<0.05).3.Morris’s Water maze test: the model group rats’ times cross the platform inMorris’s Water maze test are lower than sham-operation group rats’. the model grouprats’ latency are higher than the sham group rats’(p<0.05). The rehabilitation grouprats’ times cross the platform in Morris’s Water maze test are higer than the modelgroup rats’, the rehabilitation group rats’ latency are lower than the model group rats’(p<0.05). the rehabilitation group rats’ times cross the platform in Morris’s Watermaze test are lower than sham-operation group rats’. the rehabilitation group rats’latency are higher than the sham group rats’(p<0.05).4. New object recognition test: the model group rats’ Discrimination Index is thanthe sham group and the rehabilitation group rats’(p<0.05). the model group rats’Discrimination Index is than the sham group and the rehabilitation group rats’(p<0.05). the rehabilitation group rats’ Discrimination Index is than the shamgroup(p<0.05).5. HE staining: Compared with sham-operation group and rehabilitation group, thenumber of cells is less and sparse arrangement and vacuolar cells are more in modelgroup rats’ hippocampal DG region.6.Immunohistochemical expression results of amyloid-beta peptide: The expressionof Aβ in rehabilitation group rats’ hippocampus DG area were less than in model groupand more than in sham-operation(p<0.05).7.Immunohistochemical expression results of β-secretase: The expression of BACEin rehabilitation group rats’ hippocampus DG area were less than in model groupand more than in sham-operation(p<0.05).8.Immunohistochemical expression results of amyloid-beta peptide: The expressionof insulin-degrading enzyme in rehabilitation group rats’ hippocampus DG areawere more than in model group and less than in sham-operation(p<0.05).Conclusion: Rehabilitation training can accelerate recovery of learning andmemory ability in vascular dementia rats，and the mechanism possibly is related todecrease the accumulation of Aβ in hippocampus by increasing the expression of IDE and decreasing the expression of BACE in the hippocampus.