Morkunaite-Haimi Sarune, Kruglov Alexey G, Teplova Vera V, Stolze Klaus, Gille Lars, Nohl Hans, Saris Nils-Erik L
Department of Applied Chemistry and Microbiology, Viikki Biocentre I, University of Helsinki, P.O. Box 56, FIN-00014 Helsinki, Finland.
Biochem Pharmacol. 2003 Jan 1;65(1):43-9. doi: 10.1016/s0006-2952(02)01450-8.
Dihydrolipoic acid (DHLA) has been found to stimulate the Ca(2+)-induced mitochondrial permeability transition (MPT) in rat liver mitochondria (RLM) [Biochem. Mol. Biol. Int. 44 (1998) 127] which could be due to its prooxidant properties. We therefore investigated whether DHLA stimulated superoxide anion (O(2)(.-)) generation in RLM and in bovine heart submitochondrial particles (SMP). In RLM DHLA caused a concentration-dependent O(2)(.-) generation assayed by lucigenin chemiluminiscence. The stimulation was seen with the lowest concentrations of DHLA (5 microM) with pyruvate as the respiratory substrate, with 2-oxoglutarate or especially succinate the stimulation was less pronounced. Stimulation of O(2)(.-) production by DHLA was also observed in bovine heart SMP using an electron spin-trapping technique. Radical scavengers (butylhydroxytoluene and TEMPO) decreased O(2)(.-) generation induced by DHLA and inhibited MPT. Slight reduction of the mitochondrial membrane potential by a small amount of a protonophorous uncoupling agent also delayed the DHLA-induced MPT. These data indicate that the stimulation of MPT by DHLA is due to DHLA-derived prooxidants, i.e. stimulated production of O(2)(.-) and possibly other free radicals.
已发现二氢硫辛酸（DHLA）可刺激大鼠肝线粒体（RLM）中Ca（2+）诱导的线粒体通透性转换（MPT）[《生物化学与分子生物学国际杂志》44（1998）127]，这可能归因于其促氧化特性。因此，我们研究了DHLA是否会刺激RLM和牛心亚线粒体颗粒（SMP）中超氧阴离子（O（2）（.-））的生成。在RLM中，通过光泽精化学发光法检测，DHLA引起了浓度依赖性的O（2）（.-）生成。以丙酮酸作为呼吸底物时，在最低浓度的DHLA（5 microM）下即可观察到这种刺激作用；以2-氧代戊二酸或尤其是琥珀酸作为呼吸底物时，刺激作用则不太明显。使用电子自旋捕获技术在牛心SMP中也观察到了DHLA对O（2）（.-）生成的刺激作用。自由基清除剂（丁基羟基甲苯和TEMPO）可减少DHLA诱导的O（2）（.-）生成并抑制MPT。少量质子载体解偶联剂对线粒体膜电位的轻微降低也延迟了DHLA诱导的MPT。这些数据表明，DHLA对MPT的刺激作用归因于DHLA衍生的促氧化剂，即刺激产生的O（2）（.-）以及可能的其他自由基。
