单壁碳纳米管的肺毒性及氧化应激机制

目的 研究单壁碳纳米管(single-wall carbon nanotubes,SWCNTs)的肺毒性,并探讨其毒性机制,为安全生产和应用SWCNTs提供实验依据.方法 A549细胞用质量浓度为0、25、50、100、150、200 μg/mL的SWCNTs溶液孵育24 h,用CCK-8和乳酸脱氢酶(lactate dehydrogenase,LDH)试剂盒分别检测SWCNTs对A549细胞活性和细胞膜的影响,Hoechst 33342和PI荧光双染法检测细胞死亡情况,透射电镜(TEM)观察细胞超微结构变化,并检测细胞内活性氧(reactive oxygen species,ROS)水平、谷胱甘肽(glutathione,GSH)浓度和超氧化物歧化酶(superoxide dismutase,SOD)活力以评估氧化应激情况.分别将0.5 mg/mL和1 mg/mL的SWCNTs溶液通过气管灌流的方法使大鼠肺部染毒,3d后取大鼠肺脏,常规H-E染色,检测肺组织病理学变化.结果SWCNTs对A549细胞表现出明显毒性,使细胞活性降低,死亡细胞增多,细胞膜和细胞结构损伤严重,细胞内ROS水平升高,GSH浓度和SOD活力降低.体内毒性检测结果表明SWCNTs在大鼠肺组织内积累,造成肺泡壁水肿增厚.结论 体外细胞毒性检测和动物毒性检测结果表明SWCNTs具有较大的肺毒性,其主要毒性机制是氧化应激反应.

Pulmonary toxicity of single-wall carbon nanotubes and its oxidative stress mechanism

Objective To systematically study the pulmonary toxicity of single-wall carbon nanotubes (SWCNTs) and explore the cytotoxicity mechanism, which can provide a theoretical basis for the safe production and application of SWCNTs. Methods The cell viability and degree of cell membrane damage were assessed by CCK-8 and lactate dehydrogenase (LDH) release assay kit, and ultrastructural alteration of A549 cells was detected by using transmission electron microscope (TEM). The oxidative stress response was evaluated by assessing reactive oxygen species (ROS), glutathione (GSH) and superoxide dismutase (SOD). The rats were exposed to SWCNTs by the method of intratracheal instillation, and then the pathological sections of lung tissue were detected. Results In the cytotoxicity studies, SWCNTs showed considerable toxicity, including the decrease of cell viability, severe damage of cell membrane and ultrastructure, the increase of the intracellular ROS level, the decrease of GSH content and SOD activity. It was found that oxidative stress is the main mechanism of SWCNTs toxicity on A549 cells. In vivo toxicity results showed that SWCNTs accumulated in the lung tissue, and caused alveolar wall edema. Conclusion In vitro and in vivo toxicity results showed that SWCNTs had a significant pulmonary toxicity, and the main toxicity mechanism was oxidative stress.