Bachur José Alexandre, Garcia Sérgio Britto, Vannucchi Hélio, Jordao Alceu Afonso, Chiarello Paula Garcia, Zucoloto Sérgio
Department of Pathology, Ribeirão Preto School of Medicine, University of São Paulo, 14.049-900, Ribeirão Preto, SP, Brazil.
Appl Physiol Nutr Metab. 2007 Apr;32(2):190-6. doi: 10.1139/h06-078.
The objective of this study was to analyze the oxidative stress of skeletal muscle of sedentary rats at the morphological and biochemical level, due to acute physical effort performed at different intensities and during different periods of time. Forty-two male sedentary Wistar rats were divided into two groups, group A (swimming for 50 min) and group B (swimming for 100 min), which were further subdivided into 3 different exercise intensities, non-weight bearing (subgroup I), 3% weight load (subgroup II), and 5% weighted load (subgroup III), as well as a control-rested group (C). The animals were killed by ether inhalation and fragments of the gastrocnemius muscle were removed for the determination of malondialdehyde (MDA), reduced glutathione (GSH), and vitamin E concentrations. When all groups were compared with the control-rested group (C), gastrocnemius MDA levels at 50 and 100 min were higher at all swimming intensities. GSH consumption was greater at all intensities in group A, and only at 100 min in group BI; vitamin E consumption was significantly higher only in groups BII and BIII. When groups were compared by intensity at each swimming time there were no differences between I, II, and III at 50 min for any of the substances analyzed (MDA, GSH, and vitamin E), but at 100 min opposite effects were observed for GSH and vitamin E, with vitamin E consumption and GSH recovery occurring with increasing weight load. Higher concentrations of skeletal muscle MDA could indicate elevated lipid peroxidation at each time and exercise intensity, with highest MDA levels observed after the longest exercise duration and at the highest intensity. The layer-line mode of utilization of body antioxidants could explain the concentrations of GSH and vitamin E: first the use of GSH, even with minor oxidative stress, and then vitamin E consumption only in the presence of greater and more prolonged oxidative stress, indicating the necessity of adequate body levels of both antioxidants for proper utilization by the body antioxidant defense system.
本研究的目的是在形态学和生化水平上分析久坐不动的大鼠骨骼肌的氧化应激情况，这些应激是由不同强度和不同时间段的急性体力活动引起的。42只雄性久坐不动的Wistar大鼠被分为两组，A组（游泳50分钟）和B组（游泳100分钟），这两组又进一步细分为3种不同的运动强度，即无负重（I亚组）、3%体重负荷（II亚组）和5%体重负荷（III亚组），以及一个安静对照组（C组）。通过吸入乙醚处死动物，并取出腓肠肌碎片以测定丙二醛（MDA）、还原型谷胱甘肽（GSH）和维生素E的浓度。当将所有组与安静对照组（C组）进行比较时，在所有游泳强度下，50分钟和100分钟时腓肠肌的MDA水平均较高。A组在所有强度下GSH的消耗都更大，而B组I仅在100分钟时GSH消耗更大；维生素E的消耗仅在B组II和B组III中显著更高。当在每个游泳时间按强度对各组进行比较时，在50分钟时，对于所分析的任何物质（MDA、GSH和维生素E），I、II和III组之间均无差异，但在100分钟时，观察到GSH和维生素E有相反的效应，随着体重负荷增加，维生素E消耗增加而GSH恢复。较高浓度的骨骼肌MDA可能表明在每个时间点和运动强度下脂质过氧化增加，在最长运动持续时间和最高强度后观察到最高的MDA水平。身体抗氧化剂的分层利用模式可以解释GSH和维生素E的浓度：首先使用GSH，即使是轻微的氧化应激，然后仅在存在更大和更持久的氧化应激时才消耗维生素E，这表明身体中这两种抗氧化剂都有足够水平对于身体抗氧化防御系统的正常利用是必要的。
