药用纳米SiO2对人正常肺细胞的氧化损伤

目的：探讨药用纳米SiO2对人正常肺细胞MRC-5的生长抑制与氧化损伤作用。方法：纳米SiO2暴露于MRC-5细胞48h后,以MTT法测定其对细胞增殖的影响,HE染色观察细胞的形态学变化,并检测暴露后细胞内活性氧（ROS）和还原型谷胱甘肽（GSH）含量以及超氧化物歧化酶（SOD）活性的改变,分析纳米材料对MRC-5细胞的氧化损伤作用。结果：两种尺度（粒径21.6、48.6nm）纳米SiO2暴露浓度分别达到0.4mg/mL与1.0mg/mL以上时,细胞存活率随暴露剂量的增加而降低,IC50分别为0.8mg/mL和1.9mg/mL。细胞形态皱缩,核质凝聚。细胞内活性氧明显升高（P〈0.01）,GSH含量和SOD活性显著降低（P〈0.05）,且呈现明显的剂量效应关系。结论：较高浓度纳米SiO2直接暴露可抑制人正常肺细胞MRC-5的增殖,其机理与细胞的氧化损伤有关。

Oxidative lesions induced by medical SiO_2 nanoparticles on normal human lung cells

AIM:To investigate the medical SiO_2 nanoparticles induced cytotoxicity and its mechanism on normal human lung cells(MRC-5 cells)in vitro.METHODS:The MRC-5 cells were exposed with different concentrations of SiO_2 nanoparticles for 48 h.The cell survival rate was tested by MTT assay and the cell morphological changes were observed with HE staining.The activities of reactive oxygen species (ROS),glutathione(GSH)and supemxide dismutase (SOD)were determined to evaluate the oxidative damage after SiO_2 exposure.RESULTS:Exposure with high concentrations above 0.4 mg/mL and 1.0 mg/mL 0f 21.6 nm and 48.6 nm SiO_2 nanoparticles decreased the cell survival rate in a dose-dependent manner.The median inhibitory concentrations(IC50)were 0.8mg/mL and 1.9 mg/mL respectively.Morphological observation revealed cell shrinkage and nuclear condensation after exposure.The reduced GSH content as well as SOD activity were decreased in SiO_2 nanoparticles exposed cells than that of control.CONCLUSION:Medical SiO_2 nanoparticles exposure resuhes in a dosedependent cytotoxicity in cultured MRC-5 cells that was associated with increased oxidative stress.