Department of Molecular Biology and Genetics, Faculty of Sciences, Erzurum Technical University, Erzurum, Turkey,
Cytotechnology. 2012 Dec;64(6):687-99. doi: 10.1007/s10616-012-9449-y. Epub 2012 Mar 28.
The most potent of the dioxins, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), is a persistent and ubiquitous environmental contaminant. And the health impact of exposure to TCDD is of great concern to the general public. Recent data indicate that L-glutamine (Gln) has antioxidant properties and may influence hepatotoxicity. The objective of the present study was undertaken to explore the effectiveness of Gln in alleviating the hepatotoxicity of TCDD on primary cultured rat hepatocytes. Gln (0.5, 1 and 2 mM) was added to cultures alone or simultaneously with TCDD (0.005 and 0.01 mM). The hepatocytes were treated with TCDD and Gln for 48 h. Then cell viability was detected by [3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide] (MTT) assay and lactate dehydrogenase (LDH) release, while total antioxidant capacity (TAC), total glutathione (TGSH) and total oxidative stress (TOS) levels were determined to evaluate the oxidative injury. The DNA damage was also analyzed by liver micronucleus assay (MN) and 8-oxo-2-deoxyguanosine (8-OH-dG). The results of MTT and LDH assays showed that TCDD decreased cell viability but not L-glutamine. TCDD also increased TOS level in rat hepatocytes and significantly decreased TAC and TGSH levels. On the basis of increasing doses, the dioxin in a dose-dependent manner caused significant increases of micronucleated hepatocytes (MNHEPs) and 8-OH-dG as compared to control culture. Whereas, in cultures exposured with Gln alone, TOS levels were not changed and TAC and TGSH together were significantly increased in dose-dependent fashion. The presence of Gln with TCDD modulated the hepatotoxic effects of TCDD on primary hepatocytes cultures. Noteworthy, Gln has a protective effect against TCDD-mediated DNA damages. As conclusion, we reported here an increased potential therapeutic significance of L-glutamine in TCDD-mediated hepatic injury for the first time.
二恶英中毒性最强的 2,3,7,8-四氯二苯并对二恶英（TCDD）是一种持久性的、无处不在的环境污染物。接触 TCDD 对公众健康的影响引起了极大的关注。最近的数据表明，L-谷氨酰胺（Gln）具有抗氧化特性，可能影响肝毒性。本研究旨在探索 Gln 对原代培养大鼠肝细胞 TCDD 肝毒性的缓解作用。Gln（0.5、1 和 2mM）单独添加或与 TCDD（0.005 和 0.01mM）同时添加到培养物中。用 TCDD 和 Gln 处理肝细胞 48 小时。然后通过[3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四唑溴化物]（MTT）测定法和乳酸脱氢酶（LDH）释放来检测细胞活力，同时测定总抗氧化能力（TAC）、总谷胱甘肽（TGSH）和总氧化应激（TOS）水平来评估氧化损伤。通过肝微核试验（MN）和 8-氧-2-脱氧鸟苷（8-OH-dG）分析 DNA 损伤。MTT 和 LDH 测定结果表明，TCDD 降低了细胞活力，但不降低 L-谷氨酰胺。TCDD 还增加了大鼠肝细胞的 TOS 水平，并显著降低了 TAC 和 TGSH 水平。随着剂量的增加，二恶英以剂量依赖的方式导致微核化肝细胞（MNHEPs）和 8-OH-dG 显著增加，与对照培养物相比。然而，在单独暴露于 Gln 的培养物中，TOS 水平没有变化，并且 TAC 和 TGSH 一起呈剂量依赖性显著增加。Gln 与 TCDD 一起调节 TCDD 对原代肝细胞培养物的肝毒性作用。值得注意的是，Gln 对 TCDD 介导的 DNA 损伤具有保护作用。因此，我们首次报道了 L-谷氨酰胺在 TCDD 介导的肝损伤中的治疗意义增加。
