力竭性运动对大鼠肝脏线粒体氧化磷酸化偶联的影晌

EFFECT OF EXHAUSTIVE EXERCISE ON COUPLING OF MITOCHONDRIAL OXIDATIVE PHOSPHORYLATION IN RAT LIVER

本文以ＳＤ大鼠三级递增负荷力竭性跑台运动为疲劳模型，分别测定了运动后即刻肝脏线粒体：１．呼吸链复合体Ⅰ＋Ⅲ和Ⅱ＋Ⅲ电子传递与质子泵出比值（Ｈ＋／２ｅ）；２．以苹果酸＋谷氨酸（Ｍ＋Ｇ）和琥珀酸（Ｓ）为底物的呼吸控制：态３呼吸速率（Ｒ３）、态４呼吸速率（Ｒ４）、呼吸控制率（ＲＣＲ）和磷／氧比（Ｐ／Ｏ）。结果表明：两种呼吸底物启动的线粒体态４呼吸速率分别升高６４．４６和２３．５４％（Ｐ＜０．００１和Ｐ＜０．０５）；呼吸链复合体Ⅰ＋Ⅲ和Ⅱ＋Ⅲ的总Ｈ＋／２ｅ分别降低１８．６３和１５．８９％（均Ｐ＜０．０１）。两种呼吸底物的ＲＣＲ和Ｐ／Ｏ呈显著降低（均Ｐ＜０．０５）；Ｍ＋Ｇ为呼吸底物的态３呼吸速率也呈显著增加（Ｐ＜０．０１），Ｓ为呼吸底物的态３呼吸速率略有增高（Ｐ＞０．０５）。提示，线粒体质子漏增加，呼吸链电子传递与质子泵出偶联程度下降，氧化磷酸化脱偶联导致无效氧耗增多，可能是运动性疲劳状态下线粒体氧利用率下降的重要机制。

Rats running with an incremental intensity to exhaustion was used as an experimental model to investigate the effect of acute exhaustive exercise on the coupling of mito chondrial oxidative phosphorylation in livers. The experiment was designed to determine the functional changes of prepared mitochondria immediately after exhaustive exercise: 1. Rate of electron transfer to proton pump of mitochondrial respiratory chain complex Ⅰ+Ⅲ and Ⅱ+Ⅲ(H +/2e); 2.Parameter of mitochondrial respiratory control in the presence of Malate and Glutate (M+G), and Succinate (S): Respiratory rate of state 4 (R4), Respiratory rate of state 3 (R3), Respiratory control rate (RCR) and P/O. It was found that, in exhausted rats, R4 increased by 64.46 and 23.54% (respectively, P <0.001 and P <0.05) in the present of M+G and S; the total H +/2e of complex Ⅰ+Ⅲ and Ⅱ + Ⅲ decreased with 18.63 and 15.89% (respectively, P <0.001) as well as the decreased in RCR and P/O with both substrates ( P <0.05). However, The significant increased in R3 was observed in the present of M+G ( P <0.001), but no change in present of S ( P >0.05). The present research suggested that some important factors, such us the enhanced mitochondrial proton leak, the decreased coupling of electron transfer and proton pump, and the ineffective increase of oxygen consumption may be responsible for the decreased mitochondrial efficiency of oxygen utilization during the exercise induced fatigue.