Canadian Rivers Institute, Department of Biomedical Science, Atlantic Veterinary College , University of Prince Edward Island , Charlottetown , Canada C1A 4P3.
Department of Biomedical Science, Atlantic Veterinary College , University of Prince Edward Island , Charlottetown , Canada C1A 4P3.
Environ Sci Technol. 2018 Sep 18;52(18):10803-10811. doi: 10.1021/acs.est.8b02638. Epub 2018 Aug 24.
Naphthenic acids (NAs) are predominant compounds in oil sands influenced waters. These acids cause numerous acute and chronic effects in fishes. However, the mechanism of toxicity underlying these effects has not been fully elucidated. Due to their carboxylic acid moiety and the reported disruption of cellular bioenergetics by similar structures, we hypothesized that NAs would uncouple mitochondrial respiration with the resultant production of reactive oxygen species (ROS). Naphthenic acids were extracted and purified from 17-year-old oil sands tailings waters yielding an extract of 99% carboxylic acids with 90% fitting the classical O-NA definition. Mitochondria were isolated from rainbow trout liver and exposed to different concentrations of NAs. Mitochondrial respiration, membrane potential, and ROS emission were measured using the Oroboros fluorespirometry system. Additionally, mitochondrial ROS emission and membrane potential were evaluated with real-time flow cytometry. Results showed NAs uncoupled oxidative phosphorylation, inhibited respiration, and increased ROS emission. The effective concentration (EC) and inhibition concentration (IC) values for the end points measured ranged from 21.0 to 157.8 mg/L, concentrations similar to tailings waters. For the same end points, EC/IC values ranged from 11.8 to 66.7 mg/L, approaching concentrations found in the environment. These data unveil mechanisms underlying effects of NAs that may contribute to adverse effects on organisms in the environment.
环烷酸（NAs）是受油砂影响水域中的主要化合物。这些酸会对鱼类造成许多急性和慢性影响。然而，这些影响背后的毒性机制尚未完全阐明。由于其羧酸部分以及类似结构对细胞生物能量的报道干扰，我们假设 NAs 会使线粒体呼吸解偶联，从而产生活性氧（ROS）。从 17 年的油砂尾矿水中提取和纯化了环烷酸，得到了 99%羧酸的提取物，其中 90%符合经典的 O-NA 定义。从虹鳟鱼肝脏中分离出线粒体，并将其暴露于不同浓度的 NAs 中。使用 Oroboros 荧光计系统测量线粒体呼吸、膜电位和 ROS 发射。此外，还通过实时流式细胞术评估了线粒体 ROS 发射和膜电位。结果表明，NAs 解偶联氧化磷酸化，抑制呼吸并增加 ROS 发射。所测量终点的有效浓度（EC）和抑制浓度（IC）值范围为 21.0 至 157.8 mg/L，与尾矿水的浓度相似。对于相同的终点，EC/IC 值范围为 11.8 至 66.7 mg/L，接近环境中发现的浓度。这些数据揭示了 NAs 影响的潜在机制，这些机制可能导致环境中生物体的不良反应。
