牛磺酸拮抗同型半胱氨酸诱导的线粒体呼吸链自由基生成和同型半胱氨酸抑制线粒体牛磺酸转运体

Taurine reduced oxygen free radical production induced by homocysteine in electron transport chain and homocysteine inhibites taurine transporter in mitochondria membrane

目的 :观察同型半胱氨酸 (Hcy)对心肌线粒体电子漏及自由基生成的影响 ,以及观察牛磺酸的拮抗效应。方法 :分离大鼠心肌线粒体 ,超声波破碎线粒体制备亚线粒体 ,纯化制备猪心肌线粒体琥珀酸细胞色素C还原酶 (SCR)重组体。分别用Hcy和 /或牛磺酸共同孵育心肌线粒体、亚线粒体、SCR ;用化学发光法测定H2 O2 及O2 生成 ;并用滤膜抽滤法观察线粒体膜牛磺酸转运体的性质及Hcy对牛磺酸转运功能的影响。结果 :Hcy呈浓度依赖性地刺激大鼠心肌线粒体、亚线粒体氧自由基生成及SCR电子漏增加 ,牛磺酸自身不影响心肌线粒体、亚线粒体及SCR氧自由基生成 ,但呈浓度依赖性地抑制Hcy诱导的线粒体、亚线粒体及呼吸链重组体氧自由基生成。线粒体膜上存在Na+ 依赖性的牛磺酸转运体 ,Hcy呈浓度依赖性地抑制牛磺酸转运体对牛磺酸的转运功能。结论 :牛磺酸抑制Hcy刺激的线粒体呼吸链电子漏增加及氧自由基生成。线粒体膜上存在Na+ 依赖性的牛磺酸转运体 。

AIM: To observe effects of homocysteine and antagonized effects of taurine on electronic leakage and free radical production in myocardial mitochondria. METHODS: Myocardial mitochondria of rat heart was isolated, and was broken by supersonic wave to prepare submitochondria. Recombinant of succinic acid cytochrome c reductase was prepared with mitochondria of porcine heart. They were co-incubated with homocysteine and/or taurine with various concentration. The H_2O_2 and O_2~ were determined by chemiluminescence methods. The taurine transporter of heart mitochondria and its propert, and effects of homocysteine on its function were studied with glass filter. RESULTS: Homocysteine stimulated oxygen free radical production in heart mitochondria, submitochondria, and succinic acid cytochrome c in a concentration-dependent manner. Although taurine itself did not affect oxygen free radical production, taurine did inhibit oxygen free radical production in mitochondria, submitochondria and succinic acid cytochrome c in a concentration-dependent manner. Taurine transporters of Na^+-dependent were existed in mitochondria membrane. Homocysteine inhibited taurine transtport in mitochondria in a concentration-dependent manner. CONCLUSIONS: Taurine inhibited electronic leakage and oxygen free radical production induced by homocysteine in electron transport chain. There were taurine transporters in mitochondria membrane, and transport functions of taurine transporter were inhibited by homocysteine. [