ABSTRACT
BACKGROUND: Through exercise and/or hypoxia to increase the body's stress level and timing of hypoxia, so as to improve the body's adaptation level to exercise and/or hypoxia. However, little was known concerning the effects of acute exercise and/or hypoxia on vascular endothelial cell growth factor (VEGF) expression in skeletal muscles.OBJECTIVE: To study the effects of acute exercise and/or hypoxia on VEGF expression in rats' gastrocnemius muscles. DESIGN, TIME AND SETTING: The randomized controlled animal experiment was performed at the Clinical Laboratory, People's Hospital of Jiangsu Province, between September 2005 and September 2006.MATERIALS: Totally 108 health male SD rats were randomly divided into 6 groups, namely, normoxia quiet, normoxia high intensity, normoxia moderate intensity, hypoxia quiet, living high-training low high intensity and living high-training low high intensity moderated intensity groups, with 12 animals in each group.METHODS: In acute normoxia exercise models, rats were performed adaptive activity at 48 hours prior to experiment. The high intensity exercise was comprised of 50 m/minx1.5 min training with 2 minutes rest. The moderate intensity exercise was 30 m/min×30 min. Hypoxia environment was produced by using low oxygen instrument to simulate hypoxia training, with hypoxia for 3 days, 22 h/d, 12.8% altitude, with 22 ℃ temperature and 55% humidity. In acute training low-living high models, rats were placed in above hypoxia environment after high intensity Or moderate intensity exercise. Four rats were sacrificed at hours 0, 2 and 4 after training, and the gastrocnemius muscles were obtained.MAIN OUTCOME MEASURES: The expression of VEGF in rats' gastrocnemius muscles was detected by using western-blot.RESULTS: Hypoxia and acute normoxia exercise enhanced the expression of VEGF, hypoxia after exercise weakened exercise-induced VEGF expression, and the exercise with long time and common intensity induced the higher level VEGF expression. The expression of VEGF was the most at the time points of instantaneousness and 2 hour after exercise, the sorting of the recovery speed of VEGF changes from fast to slow was: hypoxia or training low-living high and normoxic exercise. CONCLUSION: The expressions of VEGF in rats' skeletal muscles induced by acute exercise and/or hypoxia belong to the effect of immediate-early, with existing intensity-threshold, which recovery speed is inversely proportional to the expression amplitude;"training low-living high" may be able to enhance the adaptation of skeletal muscles to sports.