Effects of treadmill training on hsp70 and casaspe-3 in ischemic brain

• Main Authors: Yi-Chin Hsieh, 謝易瑾
• Other Authors: Ray-Yau Wang
• Format: Others
• Language: en_US
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/47327412448350167084

碩士 === 國立陽明大學 === 物理治療暨輔助科技學系 === 99 === Background: Reducing neuronal damage and functional impairments are the primary goals in the clinical treatment for the stroke patients. Treadmill training is an effective intervention to improve motor function. Treadmill training is also found to reduce infarct volume administered before and after brain ischemia. Several studies have shown that treadmill training could increase heat-shock protein 70 (hsp70) up-regulations at different organs and result in anti-apoptotic effect. In transgenic animal study, over-expression of hsp70 could reduce brain ischemic damage and improve motor function. However, whether hsp70 can be up-regulated by treadmill training and result in protective effect in ischemic brain is not immediately known. The purpose of this study was to investigate the effects of treadmill training on the expression of hsp70 and caspase-3 and motor performance in brain ischemic rats. Material and methods: Rats were randomly assigned to experimental or control group. Rats in both groups underwent middle cerebral artery occlusion (MCAO) for 1 hr. Twenty-four hrs after MCAO, rats in the experimental group received treadmill training for 1 day, 3 days, 1 week, or 2 weeks and rats in the comparable control group was remained relatively inactive for 1 day, 3 days, 1 week, or 2 weeks respectively. Treadmill training intensity was set at 20 m/min, 30 min/day. Motor function was assessed by ladder climbing test. The hsp70 and caspase-3 expression were measured by westerner blot. Normal rats were used for baseline data. Two-way ANOVA was used for statistical analysis. If the results of two-way ANOVA indicated a significant effect, post-hoc analysis was carried out by using the one-way ANOVA with Tukey post-hoc test. All data were expressed as mean±SEM, and significance was set at p<0.05. Results: Our data showed that the motor function improved significantly after treadmill training at least for 1 week. The cortex hsp70 expression level was high after 1 day of relatively inactive and declined in the following 2 weeks in the control group. However, the cortex hsp70 expression was maintained in the experimental group. The significant differences of hsp70 expression between control and experimental groups were noted after 1 and 2 weeks of training. The caspase-3 expression level was not changed significantly after treadmill training. Conclusions: Treadmill training can result in motor function improvement which paralleled with hsp70 expression. However, the anti-apoptotic effect of hsp70 may not be the reason for motor function improvement since the major apoptosis indicator – caspase-3 was not changed significantly. Other possible effects of hsp70, such as anti-inflammation or trophic effects may account for the neuroprotection of post-ischemic treadmill training.