急性运动中骨骼肌线粒体活性氧生成与解偶联的反馈调节  

A Feedback Molecular Regulation of Uncoupling and ROS Generation in Muscular Mitochondria during an Acute Exercise

作　　者：张勇[1] 张桂忠[1] 姜宁[1] 马国栋[1] 文立[1] 薄海[1] 曹东宁[1] 赵斐[1] 刘树森[2] 

机构地区：[1]天津体育学院运动医学研究所,运动人体科学系天津300381 [2]中国科学院动物研究所生物膜与膜生物工程国家重点实验室

出　　处：《中国运动医学杂志》2005年第4期389-394,414,共7页Chinese Journal of Sports Medicine

基　　金：国家自然科学基金(No.30270638和No.30470837)共同资助

摘　　要：目的:线粒体呼吸链电子漏是运动性内源活性氧(ROS)生成的重要机制之一。目前的研究表明,线粒体呼吸链“温和解偶联”机制也参与了线粒体内的抗氧化防御过程。本研究拟证实运动是否也不同程度地诱导和/或启动了线粒体呼吸链“温和解偶联”生物抗氧化机制,并探讨其可能的分子调节作用和生理意义。方法:以SD大鼠三级递增负荷跑台运动为实验模型,分别选取安静态、运动45、90、120和150min为实验观察点(timecourse),测定骨骼肌线粒体ROS生成、线粒体态4呼吸速率、骨骼肌解偶联蛋白3(UCP-3)mRNA和线粒体UCP-3蛋白表达。结果:运动过程中ROS生成呈先上升后下降的变化趋势,其中运动至45、90、120min时均较安静时显著升高(分别为P<0.05、P<0.001和P<0.001),于120min达到峰值,随后(150min时)显著下降(与120min组相比,P<0.001);态4呼吸速率亦呈先上升后下降的并行性变化趋势,其中运动90、120min较安静时显著增加(分别为P<0.01和P<0.001),并于120min达到峰值,随后(150min时)显著降低(与120min组相比,P<0.001);UCP-3mRNA在运动至90、120、150min时均较安静时显著升高(分别为P<0.001、P<0.01和P<0.01),其蛋白表达水平则相对滞后1个时间段,先后在运动至120、150min时较安静时显著增加(均为P<0.001)。结论:线粒体态4呼吸速率、ROS生成和UCP-3表达随运动时间的变化表明,ROS可能贡献于运动中骨骼肌线粒体UCP-3的激活和/或诱导表达;运动中UCP-3表达增加的意义在于抑制ROS生成,并且由ROS→UCP-3→质子漏→ROS形成一个复杂而精确的激活、诱导表达与抗氧化的反馈调节环路,使线粒体能够尽早预防运动可能引发的氧化应激和脂质过氧化,维持线粒体及细胞内的氧化还原状态。Objective The purpose of this study was to investigate whether mitochondrial mild uncoupling was induced and/or activated during strenuous exercise and to explore its possible molecular regulation. Meth-ods SD rats were divided into 5 groups:resting and running for 45, 90, 120 and 150 min, respectively, on the treadmill according to the Bedford's incremental protocol and sacrificed at rest or immediately after every exercise time course. The following parameters were determined: (1) Separated mitochondrial state 4 rate in the presence of malate and glutate by Clark Oxygen Electrode; (2) ROS generation of separated mitochondria by fluorometric probe; (3) Expression of UCP-3 mRNA in muscle homogenate and its protein in mitochondria using RT-PCR and Western Blotting, respectively. Results (1) Mitochondrial ROS generation was significant higher at 45, 90, 120 min than at rest (P < 0.05, P < 0.001 and P < 0.001, respectively) with its peak at the point of 120 min, and declined obviously at 150 min subsequently (P<0.001); (2)State 4 rate increased significantly in parallel with ROS generation at 90 and 120 min (P<0.01 and P< 0.001 respectively) and lowered when exercising at 150 min (P<0.001); (3) There were remarkably higher levels of UCP-3 mRNA at 90, 120 and 150 min (P<0.001, P<0.01 and P<0.01 respectively), and followed with increase in UCP-3 protein contents at 120 and 150 min (both P<0.001). Conclusions According to the observation, we hypothesized that ROS might contribute to activate and/or induce expression of UCPs. UCPs could cause mild uncoupling in response to matrix superoxide and other oxidants during exercise, and constitute a self-limiting cycle to protect against excessive superoxide production, leading to early protection against oxidation and regulation of cellular and mitochondrial redox.

关 键 词：骨骼肌线粒体 反馈调节 活性氧生成 急性运动 线粒体呼吸链 呼吸链电子漏 分子调节作用 呼吸速率 蛋白表达水平 氧化还原状态 诱导表达 ROS 抗氧化机制 解偶联蛋白 脂质过氧化 线粒体内 不同程度 生理意义 实验模型 跑台运动 

分 类 号：R87[医药卫生—运动医学]