Department of Pharmacology, Catholic University of Daegu, Republic of Korea.
Chemosphere. 2010 Apr;79(3):278-84. doi: 10.1016/j.chemosphere.2010.01.040. Epub 2010 Feb 12.
Positive associations of halogenated aromatic hydrocarbons and arthritis have been reported in human populations. Although 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most potent congener of its class, is associated with musculoskeletal dysfunctions in humans and animals, its role on arthritis remains unknown. Apoptosis of chondrocytes has become a focus of interest in the pathogenesis of arthritis. We investigated the potential of TCDD as an inducer of chondrocyte apoptosis and evaluated its mechanism of action. Rabbit chondrocytes in culture were exposed to TCDD. Responses of dioxin-responsive genes and enzyme activity were analyzed by RT-PCR and EROD assay, respectively. Generation of reactive oxygen species (ROS) and nitric oxide (NO) were also determined. A panel of different approaches including caspase-3 assay, ELISA, flow cytometry, and TUNEL staining was utilized to detect apoptotic effects. Dioxin induced mRNAs of dioxin-responsive genes and EROD activity in an AhR-dependent manner. Dose-dependent increases in ROS and NO production were observed. All apoptosis detection techniques used in this study revealed an increase of apoptotic effects in a dose-dependent manner. The increase of apoptosis was blocked by inhibitors of ROS or NO, suggesting that apoptotic effects may be mediated via ROS- and NO-dependent pathways. This is a first report to demonstrate the potential of TCDD to induce apoptosis in chondrocytes, which could be an initial process in cartilage degradation. This finding may shed a new light in studying the possible role of environmental pollutants in the etiology of arthritis.
在人类群体中，已报道卤代芳烃与关节炎之间存在正相关关系。虽然 2,3,7,8-四氯二苯并对二恶英（TCDD）是同类物质中最具活性的一种，它与人类和动物的肌肉骨骼功能障碍有关，但它在关节炎中的作用仍不清楚。软骨细胞凋亡已成为关节炎发病机制研究的一个焦点。我们研究了 TCDD 作为软骨细胞凋亡诱导剂的潜力，并评估了其作用机制。在培养的兔软骨细胞中暴露于 TCDD。通过 RT-PCR 和 EROD 测定分别分析二恶英反应基因和酶活性的反应。还测定了活性氧（ROS）和一氧化氮（NO）的产生。采用一系列不同的方法，包括 caspase-3 测定、ELISA、流式细胞术和 TUNEL 染色，来检测凋亡效应。二恶英以 AhR 依赖的方式诱导二恶英反应基因的 mRNA 和 EROD 活性。观察到 ROS 和 NO 产生呈剂量依赖性增加。本研究中使用的所有凋亡检测技术均显示出剂量依赖性增加的凋亡效应。ROS 或 NO 的抑制剂可阻断凋亡的增加，表明凋亡效应可能通过 ROS 和 NO 依赖途径介导。这是首次报道 TCDD 有潜力诱导软骨细胞凋亡，这可能是软骨降解的初始过程。这一发现可能为研究环境污染物在关节炎发病机制中的可能作用提供新的思路。
