纳米氧化锌颗粒对大鼠气管上皮细胞动态变化的影响及毒性机理

纳米氧化锌(Zn O NPs)对呼吸道的毒性损伤作用备受关注,但有关其对呼吸道上皮细胞动态变化的影响机理还有待深入研究.因此,本研究通过将大鼠气管上皮细胞(RTE)暴露于不同浓度(1和10 mg·L~(-1))和不同粒径(50和200 nm)的Zn O NPs中,利用细胞电阻抗检测技术(ECIS)检测细胞动态变化,采用CCK8法检测细胞生长抑制效应,并通过胞内ROS和MDA含量变化探讨其影响机制.ECIS检测结果显示,Zn O NPs暴露下,RTE细胞生长和增殖受到明显抑制,且具有浓度依赖效应.当暴露浓度为1 mg·L~(-1)时,与对照组相比,50 nm暴露组细胞电阻抗值的下调幅度为18%,为200 nm暴露组的1.2倍.Zn O NPs诱导的RTE细胞增殖抑制率具有浓度依赖效应,当暴露浓度为10 mg·L~(-1)时,50和200 nm暴露组细胞增殖抑制率分别为暴露浓度为1 mg·L~(-1)时的2.9和1.4倍.Zn O NPs诱导的RTE细胞氧化应激结果显示,胞内ROS和MDA含量随着纳米颗粒暴露浓度的增加而增加,随着纳米颗粒粒径的减小而增加,具有显著的浓度-和剂量-依赖效应.当Zn O NPs浓度分别为1和10 mg·L~(-1)时,ROS含量分别是对照组的2.8和3.7倍;当暴露浓度为10 mg·L~(-1)时,50 nm暴露组细胞内ROS含量是200 nm暴露组的1.7倍;暴露浓度为1和10 mg·L~(-1)时,50 nm氧化锌处理组诱导的细胞内MDA含量分别是对照组的5.4和7.9倍.Zn O NPs能够影响呼吸道上皮细胞动态变化,从而破环RTE细胞屏障并进入细胞,诱导胞内ROS和MDA水平升高,进而抑制细胞的生长与增殖.研究表明,影响Zn O NPs诱导的RTE细胞动态变化和氧化应激的关键因素是颗粒粒径与暴露浓度.

The effect and toxicity mechanism of the dynamic change of rat tracheal epithelial cells induced by zinc oxide nanoparticles

The toxic effects of zinc oxide nanoparticles (ZnO NPs) on the respiratory tract have attracted much attention, and the mechanism of the dynamic changeof respiratory epithelial cells remains to be further studied. In the present study, rat tracheal epithelial cells (RTE cells) were exposed to ZnO NPs with different diameters (50 nm and 200 nm) and concentrations (1 mg·L^-1 and 10 mg·L^-1) for 12 h. Electric cell-substrate impedance sensing was used to detect cell dynamic changes. Using CCK8 method to detect the cell growth inhibition and the mechanism was illustrated by detecting intercellular ROS level and MDA content. The results of ECIS showed that the growth and proliferation of RTE cells was inhibited with a dose-dependent effect after ZnO NPs exposure. Compared with the control group, cell electrical impedance of the 50 nm ZnO NPs exposed group dropped to 18% in the 1 mg·L^-1 treatment group, which is 1.2-fold in the 200 nm treatment group. RTE cell proliferation inhibition rates was in a concentration dependent manner induced by ZnO NPs. The proliferation inhibition rate of RTE cells in 50 nm and 200 nm exposed groups was 2.9-fold and 1.4-fold when the exposure concentration was 10 mg·L^-1, and 1 mg·L^-1, respectively. The results showed that the ROS levels and MDA contents increased with the increase of exposure concentration and the decrease of nanoparticle size, and showed a significant concentration and dose dependent effects induced by ZnO NPs in RTE cells. The ROS level was 2.8-fold and 3.7-fold in the 1 mg·L^-1 and 10 mg·L^-1 treatment group compared to the control group. When the exposure concentration was 10 mg·L^-1, the intracellular ROS content in the 50 nm exposure group was 1.7-fold higher than that of the 200 nm exposure group. The intracellular MDA content was 5.4-fold and 7.9-fold higher than that of the control group induced by 50 nm treatment group when the exposure concentration was 1 mg·L^-1 and 10 mg·L^-1. ZnO NPs can affect the RTE cells dynamic change, disrupt the cell barrier function and enter the cells, cause an increase in intracellular ROS and MDA levels and inhibit cell growth and proliferation. The key factors affecting the RTE cells dynamic changes and oxidative stress are particle size and exposure concentration of ZnO NPs.