Reddy S K, Husain K, Schlorff E C, Scott R B, Somani S M
Department of Pharmacology, Southern Illinois University School of Medicine, Springfield 62794-9629, USA.
Neurotoxicology. 1999 Dec;20(6):977-87.
This study investigated the response of the antioxidant defense system in brain subcellular fractions after oral graded doses of ethanol to rat. Four groups of male Fischer-344 rats were orally administered saline, ethanol 2 g, 4 g, and 6 g/kg, respectively, and sacrificed 1 hour post treatment. Brain cytosol, synaptosomes, microsomes and mitochondria were separated by density gradient differential centrifugation and assayed for antioxidant system. A significant and dose-dependent-decrease in superoxide dismutase (SOD) activity was observed in all brain subcellular fractions. Catalase (CAT) activity was significantly decreased in brain mitochondria (67% and 80% of control) at higher doses of ethanol; whereas, CAT activity was significantly increased in cytosol, synaptosomes and microsomes. Glutathione peroxidase (GSH-Px) activity was significantly increased in all brain subcellular fractions except in cytosol at higher dose of ethanol. Malondialdehyde (MDA) content was significantly increased in all brain subcellular fractions showing dose response of ethanol-induced oxidative stress. The increase in MDA levels in the brain synaptosomes and microsomes were higher at 6 g dose of ethanol (155% and 163% of control) when compared to mitochondria and cytosol. Glutathione (GSH) levels were significantly increased in brain cytosol and microsomes at higher dose of ethanol (164% and 159% of control); whereas, the GSH concentration was significantly decreased in brain synaptosomes and mitochondria. The antioxidant enzyme (AOE) activity ratios (GSH-Px/SOD and GSH-Px + CAT/SOD) were dose dependently increased in all brain subcellular fractions, particularly in synaptosomes. The GSH/GSSG ratio was dose dependently increased in brain microsomes. The perturbations in the antioxidant defense system and enhanced lipid peroxidation following graded doses of ethanol ingestion indicate a dose-dependent-oxidative 2133stress response in brain subcellular compartments of rats.
本研究调查了给大鼠口服不同剂量乙醇后，其脑亚细胞组分中抗氧化防御系统的反应。将四组雄性Fischer-344大鼠分别口服生理盐水、2 g/kg、4 g/kg和6 g/kg乙醇，处理1小时后处死。通过密度梯度差速离心分离脑细胞质、突触体、微粒体和线粒体，并检测抗氧化系统。在所有脑亚细胞组分中均观察到超氧化物歧化酶（SOD）活性显著且呈剂量依赖性降低。在较高剂量乙醇作用下，脑线粒体中的过氧化氢酶（CAT）活性显著降低（为对照组的67%和80%）；而在细胞质、突触体和微粒体中，CAT活性显著增加。除较高剂量乙醇作用下的细胞质外，所有脑亚细胞组分中的谷胱甘肽过氧化物酶（GSH-Px）活性均显著增加。所有脑亚细胞组分中丙二醛（MDA）含量均显著增加，显示出乙醇诱导的氧化应激的剂量反应。与线粒体和细胞质相比，在6 g/kg乙醇剂量下，脑突触体和微粒体中MDA水平的升高更高（分别为对照组的155%和163%）。在较高剂量乙醇作用下，脑细胞质和微粒体中的谷胱甘肽（GSH）水平显著增加（分别为对照组的164%和159%）；而在脑突触体和线粒体中，GSH浓度显著降低。所有脑亚细胞组分中抗氧化酶（AOE）活性比值（GSH-Px/SOD和GSH-Px + CAT/SOD）均呈剂量依赖性增加，尤其是在突触体中。脑微粒体中GSH/GSSG比值呈剂量依赖性增加。分级摄入乙醇后抗氧化防御系统的紊乱和脂质过氧化增强表明大鼠脑亚细胞区室中存在剂量依赖性氧化应激反应。
