Song Woo-Ju, Jeong Myung-Seon, Choi Dong-Min, Kim Kil-Nam, Wie Myung-Bok
Department of Veterinary Toxicology, College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon 24341, Korea.
Chuncheon Center, Korean Basic Science Institute, Chuncheon 24341, Korea.
Nanomaterials (Basel). 2019 Jul 21;9(7):1043. doi: 10.3390/nano9071043.
The present study examined the potential toxic concentrations of zinc oxide nanoparticles (ZnO NPs) and associated autophagy and apoptosis-related injuries in primary neocortical astrocyte cultures. Concentrations of ZnO NPs ≥3 μg/mL induced significant toxicity in the astrocytes. At 24 h after exposure to the ZnO NPs, transmission electron microscopy revealed swelling of the endoplasmic reticulum (ER) and increased numbers of autophagolysosomes in the cultured astrocytes, and increased levels of LC3 (microtubule-associated protein 1 light chain 3)-mediated autophagy were identified by flow cytometry. Apoptosis induced by ZnO NP exposure was confirmed by the elevation of caspase-3/7 activity and 4',6'-diamidino-2-phenylindole (DAPI) staining. Significant ( < 0.05) changes in the levels of glutathione peroxidase, superoxide dismutase, tumor necrosis factor (TNF-α), and interleukin-6 were observed by enzyme-linked immunoassay (ELISA) assay following the exposure of astrocyte cultures to ZnO NPs. Phosphatidylinositol 3-kinase (PI3K)/mitogen-activated protein kinase (MAPK) dual activation was induced by ZnO NPs in a dose-dependent manner. Additionally, the Akt (protein kinase B) inhibitor BML257 and the mTOR (mammalian target of rapamycin) inhibitor rapamycin contributed to the survival of astrocytes. Inhibitors of cyclooxygenase-2 and lipoxygenase attenuated ZnO NP-induced toxicity. Calcium-modulating compounds, antioxidants, and zinc/iron chelators also decreased ZnO NP-induced toxicity. Together, these results suggest that ZnO NP-induced autophagy and apoptosis may be associated with oxidative stress and the inflammatory process in primary astrocyte cultures.
本研究检测了氧化锌纳米颗粒(ZnO NPs)的潜在毒性浓度以及原代新皮质星形胶质细胞培养物中相关的自噬和凋亡相关损伤。ZnO NPs浓度≥3μg/mL时可诱导星形胶质细胞产生显著毒性。暴露于ZnO NPs后24小时,透射电子显微镜显示培养的星形胶质细胞内质网肿胀且自噬溶酶体数量增加,通过流式细胞术鉴定出微管相关蛋白1轻链3(LC3)介导的自噬水平升高。ZnO NP暴露诱导的凋亡通过半胱天冬酶-3/7活性升高和4',6'-二脒基-2-苯基吲哚(DAPI)染色得以证实。星形胶质细胞培养物暴露于ZnO NPs后,通过酶联免疫吸附测定(ELISA)检测发现谷胱甘肽过氧化物酶、超氧化物歧化酶、肿瘤坏死因子(TNF-α)和白细胞介素-6水平发生了显著(<0.05)变化。ZnO NPs以剂量依赖性方式诱导磷脂酰肌醇3-激酶(PI3K)/丝裂原活化蛋白激酶(MAPK)双重激活。此外,Akt(蛋白激酶B)抑制剂BML257和雷帕霉素靶蛋白(mTOR)抑制剂雷帕霉素有助于星形胶质细胞存活。环氧合酶-2和脂氧合酶抑制剂可减轻ZnO NP诱导的毒性。钙调节化合物、抗氧化剂以及锌/铁螯合剂也可降低ZnO NP诱导的毒性。总之,这些结果表明,ZnO NP诱导的自噬和凋亡可能与原代星形胶质细胞培养物中的氧化应激和炎症过程有关。