Grosicka-Maciag E, Kurpios D, Czeczot H, Szumiło M, Skrzycki M, Suchocki P, Rahden-Staroń I
Department of Biochemistry, Medical University of Warsaw, 02-097 Warszawa, Banacha 1, Poland.
Toxicol In Vitro. 2008 Feb;22(1):28-35. doi: 10.1016/j.tiv.2007.07.006. Epub 2007 Jul 26.
The role of antioxidant defence systems in protection against oxidative damage of lipids and proteins induced by fungicide thiram during in vitro exposure was investigated in cultured Chinese hamster V79 cells with normal, depleted, and elevated glutathione (GSH) levels. We analyzed the catalytic activities of superoxide dismutases (SOD1 and SOD2), Se-dependent and Se-independent glutathione peroxidases (GSH-Px), glutathione reductase (GR), and catalase (CAT), as well as total glutathione/glutathione disulfide ratio (GSH(total)/GSSG). Thiram treatment resulted in an increase in activities of SOD1, Se-dependent GSH-Px, and GR at the highest tested dose (150 microM). On the contrary, inhibition of CAT and Se-independent GSH-Px activities, and no significant changes in the level of SOD2 activity was observed at any tested doses (100-150 microM). GSH(total)/GSSG ratio in the 100 microM thiram treated cells was not significantly changed comparing to the control, despite significant decrease of GSH total (50%). In 150 microM thiram treated cells the ratio falls to 43% of control value. Pretreatment with l-buthionine sulfoximine (L-BSO), an inhibitor of GSH synthesis, significantly enhanced decrease in CAT and Se-independent GSH-Px activities, as well as GSH(total)/GSSG ratio, and reduced Se-dependent GSH-Px activity, following exposure to thiram. Simultaneously, L-BSO pretreatment enhanced increase in SOD1 activity, and had no effect on SOD2, following thiram exposure. Pretreatment with N-acetyl cysteine (NAC), a GSH precursor, prevented enzymatic changes in CAT, Se-dependent GSH-Px, GR, SOD1 activities, and significantly decreased SOD2 activity following exposure to thiram. GSH(total)/GSSG ratio was restored to the control value. This study suggests that following the changes in antioxidant defense systems thiram can act through the production of free radicals.
在体外暴露过程中，研究了抗氧化防御系统在保护培养的中国仓鼠V79细胞免受杀菌剂福美双诱导的脂质和蛋白质氧化损伤中的作用，这些细胞具有正常、耗尽和升高的谷胱甘肽（GSH）水平。我们分析了超氧化物歧化酶（SOD1和SOD2）、硒依赖性和非硒依赖性谷胱甘肽过氧化物酶（GSH-Px）、谷胱甘肽还原酶（GR）和过氧化氢酶（CAT）的催化活性，以及总谷胱甘肽/谷胱甘肽二硫化物比率（GSH(total)/GSSG）。在最高测试剂量（150微摩尔）下，福美双处理导致SOD1、硒依赖性GSH-Px和GR的活性增加。相反，在任何测试剂量（100 - 150微摩尔）下，均观察到CAT和非硒依赖性GSH-Px活性受到抑制，且SOD2活性水平无显著变化。与对照相比，100微摩尔福美双处理的细胞中GSH(total)/GSSG比率无显著变化，尽管GSH总量显著降低（50%）。在150微摩尔福美双处理的细胞中，该比率降至对照值的43%。用GSH合成抑制剂L-丁硫氨酸亚砜胺（L-BSO）预处理，在暴露于福美双后，显著增强了CAT和非硒依赖性GSH-Px活性以及GSH(total)/GSSG比率的降低，并降低了硒依赖性GSH-Px活性。同时，L-BSO预处理增强了福美双暴露后SOD1活性的增加，且对SOD2无影响。用GSH前体N-乙酰半胱氨酸（NAC）预处理，可防止CAT、硒依赖性GSH-Px、GR、SOD1活性的酶学变化，并在暴露于福美双后显著降低SOD2活性。GSH(total)/GSSG比率恢复到对照值。这项研究表明，在抗氧化防御系统发生变化后，福美双可通过产生自由基发挥作用。
