Author: | Ke, Zheng |
Title: | Effects of different exercises on neurochemical and functional changes after brain ischemia : an experimental study |
Degree: | Ph.D. |
Year: | 2012 |
Subject: | Cerebrovascular disease -- Patients -- Rehabilitation. Hong Kong Polytechnic University -- Dissertations |
Department: | Interdisciplinary Division of Biomedical Engineering |
Pages: | xvii, 168 p. : ill. (some col.) ; 30 cm. |
Language: | English |
Abstract: | Strokes remain one of the major causes of mortality and long term disability throughout the world. Exercise paradigms have been effective rehabilitation tools in facilitating motor function recovery after strokes. Challenges in stroke rehabilitation with exercise interventions include the time window for training, the selection of different types of exercise and the mechanisms of exercise-induced recovery. Particularly, the effects of different exercise paradigms are still largely unexplored and not systematically compared. In this study, neurological deficits and cerebrovascular changes along the stroke-recovery process are investigated; the effectiveness of the voluntary, involuntary, and forced exercises in stroke rehabilitation are compared; and the possible mechanisms of the exercise-induced recovery are proposed. 100 adult Sprauge-Dowley (SD) rats were used in a pilot study to compare the ischemic stroke and hemorrhagic stroke models using ultrasonography technique and the ischemic rat model was set up after comparison. The effectiveness of different exercise interventions in stroke rehabilitation was then investigated. 150 SD rats were used at this stage. After accommodation, 33 rats were dropped-out and the remaining 117 rats were randomly distributed into four groups: Control (Con), Voluntary exercise of wheel running (V-Ex), Forced exercise of treadmill running (F-Ex), and Involuntary exercise of functional electrical stimulation (I-Ex). Ischemic strokes were induced in all group rats and 57 survival rats had motor deficits after the stroke surgery. The behavioral test and the beam walking test were conducted daily during the 7-day intervention as evaluation tools of motor recovery. Serum corticosterone and brain-derived neurotrophic factor (BDNF) levels in the hippocampus, striatum, and cortex were measured after the rats were sacrificed. The results showed that the V-Ex group had significantly higher score in the behavioral test than all the other groups and significantly higher hippocampal BDNF concentration than the F-Ex and Con groups. On the other hand, the F-Ex group had significantly higher serum corticosterone level than the other groups. The significance of this study showed that the voluntary exercise was the most effective intervention in upregulating the hippocampal BDNF level, facilitating motor recovery, and suppressing the stress response. The results also suggested that the forced exercise was the least preferred intervention with high stress, low brain BDNF levels and less motor recovery. |
Rights: | All rights reserved |
Access: | open access |
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