Lei Hao-Jun, Wei Xin-Rong, Li Li-Xia, Sun Wei-Jun, Chen Hong-Xing, Li Dan, Xie Lingtian
SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, 510006, China; School of Environment, South China Normal University, Guangzhou, 510006, China.
801 Institute of Hydrogeology and Engineering Geology, Shandong Provincial Bureau of Geology and Mineral Resources, Jinan, 250014, China; Shandong Engineering Research Center for Environmental Protection and Remediation on Groundwater, Jinan, 250014, China.
Chemosphere. 2023 Oct;337:139301. doi: 10.1016/j.chemosphere.2023.139301. Epub 2023 Jun 26.
Clozapine is an often prescribed neuroactive pharmaceutical and frequently detected in the aquatic environments. However, its toxicity on low trophic level species (i.e., diatoms) and associated mechanisms are seldom reported. In this study, the toxicity of clozapine on a widely distributed freshwater diatom Navicula sp. was evaluated using the FTIR spectroscopy along with biochemical analyses. The diatoms were exposed to various concentrations of clozapine (0, 0.01, 0.05, 0.10, 0.50, 1.00, 2.00, 5.00 mg/L) for 96 h. The results revealed that clozapine reached up to 392.8 μg/g in the cell wall and 550.4 μg/g within the cells at 5.00 mg/L, suggesting that clozapine could be adsorbed extracellularly and accumulated intracellularly in diatoms. In addition, hormetic effects were displayed on the growth and photosynthetic pigments (chlorophyll a and carotenoid) of Navicula sp., with a promotive effect at concentrations less than 1.00 mg/L while an inhibited effect at concentrations over 2 mg/L. Clozapine induced oxidative stress in Navicula sp., accompanied by decreased levels of total antioxidant capacity (T-AOC) (>0.05 mg/L), in which, the activity of superoxide dismutase (SOD) (at 5.00 mg/L) was increased whereas the activity of catalase (CAT) (>0.05 mg/L) was decreased. Furthermore, FTIR spectroscopic analysis showed that exposure to clozapine resulted in accumulation of lipid peroxidation products, increased sparse β-sheet structures, and altered DNA structures in Navicula sp. This study can facilitate the ecological risk assessment of clozapine in the aquatic ecosystems.
氯氮平是一种常用的神经活性药物，在水生环境中经常被检测到。然而，其对低营养级物种（即硅藻）的毒性及相关机制鲜有报道。在本研究中，采用傅里叶变换红外光谱（FTIR）结合生化分析，评估了氯氮平对广泛分布的淡水硅藻舟形藻属（Navicula sp.）的毒性。将硅藻暴露于不同浓度的氯氮平（0、0.01、0.05、0.10、0.50、1.00、2.00、5.00 mg/L）中96小时。结果显示，在5.00 mg/L时，氯氮平在细胞壁中的含量高达392.8 μg/g，在细胞内的含量为550.4 μg/g，这表明氯氮平可在硅藻细胞外吸附并在细胞内积累。此外，氯氮平对舟形藻属的生长和光合色素（叶绿素a和类胡萝卜素）表现出 hormetic 效应，浓度低于1.00 mg/L时有促进作用，而浓度超过2 mg/L时则有抑制作用。氯氮平诱导舟形藻属产生氧化应激，伴随着总抗氧化能力（T-AOC）水平降低（>0.05 mg/L），其中，超氧化物歧化酶（SOD）的活性（在5.00 mg/L时）增加，而过氧化氢酶（CAT）的活性（>0.05 mg/L）降低。此外，FTIR光谱分析表明，暴露于氯氮平会导致舟形藻属中脂质过氧化产物积累、β-折叠结构稀疏增加以及DNA结构改变。本研究有助于评估氯氮平在水生生态系统中的生态风险。
