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ZnO Nanoparticles Treatment Induces Apoptosis by Increasing Intracellular ROS Levels in LTEP-a-2 Cells.

Wang C, Hu X, Gao Y, Ji Y - Biomed Res Int (2015)

Bottom Line: Both intracellular reactive oxygen species (ROS) and reduced glutathione (GSH) were examined by a microplate-reader method.Results showed that ZnO NPs (≥ 0.01 μg/mL) significantly inhibited proliferation (P < 0.05) and induced substantial apoptosis in LTEP-a-2 cells after 4 h of exposure.The intracellular ROS level rose up to 30-40% corresponding to significant depletion (approximately 70-80%) in GSH content in LTEP-a-2 cells (P < 0.05), suggesting that ZnO NPs induced apoptosis mainly through increased ROS production.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, 17 Chunhui Road, Laishan District, Yantai 264003, China ; University of Chinese Academy of Sciences, Beijing 100049, China.

ABSTRACT
Owing to the wide use of novel nanoparticles (NPs) such as zinc oxide (ZnO) in all aspects of life, toxicological research on ZnO NPs is receiving increasing attention in these days. In this study, the toxicity of ZnO NPs in a human pulmonary adenocarcinoma cell line LTEP-a-2 was tested in vitro. Log-phase cells were exposed to different levels of ZnO NPs for hours, followed by colorimetric cell viability assay using tetrazolium salt and cell survival rate assay using trypan blue dye. Cell morphological changes were observed by Giemsa staining and light microscopy. Apoptosis was detected by using fluorescence microscopy and caspase-3 activity assay. Both intracellular reactive oxygen species (ROS) and reduced glutathione (GSH) were examined by a microplate-reader method. Results showed that ZnO NPs (≥ 0.01 μg/mL) significantly inhibited proliferation (P < 0.05) and induced substantial apoptosis in LTEP-a-2 cells after 4 h of exposure. The intracellular ROS level rose up to 30-40% corresponding to significant depletion (approximately 70-80%) in GSH content in LTEP-a-2 cells (P < 0.05), suggesting that ZnO NPs induced apoptosis mainly through increased ROS production. This study elucidates the toxicological mechanism of ZnO NPs in human pulmonary adenocarcinoma cells and provides reference data for application of nanomaterials in the environment.

No MeSH data available.


Related in: MedlinePlus

Relative viability of LTEP-a-2 cells after 4–24 h of exposure to different concentrations of ZnO nanoparticles (0 μg/mL, control). (a) 4 and 8 h and (b) 12 and 24 h. ∗ versus control, P < 0.05; ∗∗ versus control, P < 0.01 by Student's t-test.
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fig2: Relative viability of LTEP-a-2 cells after 4–24 h of exposure to different concentrations of ZnO nanoparticles (0 μg/mL, control). (a) 4 and 8 h and (b) 12 and 24 h. ∗ versus control, P < 0.05; ∗∗ versus control, P < 0.01 by Student's t-test.

Mentions: The cytotoxicity of ZnO NPs in LTEP-a-2 cells was tested by MTT assay using a protocol adopted from previously published reports and manufacturer's instructions [9, 25, 26], expressed as the percentage of cell mortality relative to the control treatment (Figure 2). After 4–24 h of exposure to ZnO NPs (0.01–1.5 μg/mL), cell viability declined substantially in a concentration- and time-dependent manner; the declines were especially significant after 8 h of exposure to ZnO NPs ≥ 0.25 μg/mL (P < 0.05). The number of cell deaths among all these doses has been nearly 20% higher than the lower doses over the past 24 h. High cytotoxicity can be observed in cells treated with ZnO NPs when compared to control group. These results indicate that cell proliferation was inhibited significantly with increasing concentration of ZnO NPs.


ZnO Nanoparticles Treatment Induces Apoptosis by Increasing Intracellular ROS Levels in LTEP-a-2 Cells.

Wang C, Hu X, Gao Y, Ji Y - Biomed Res Int (2015)

Relative viability of LTEP-a-2 cells after 4–24 h of exposure to different concentrations of ZnO nanoparticles (0 μg/mL, control). (a) 4 and 8 h and (b) 12 and 24 h. ∗ versus control, P < 0.05; ∗∗ versus control, P < 0.01 by Student's t-test.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4538331&req=5

fig2: Relative viability of LTEP-a-2 cells after 4–24 h of exposure to different concentrations of ZnO nanoparticles (0 μg/mL, control). (a) 4 and 8 h and (b) 12 and 24 h. ∗ versus control, P < 0.05; ∗∗ versus control, P < 0.01 by Student's t-test.
Mentions: The cytotoxicity of ZnO NPs in LTEP-a-2 cells was tested by MTT assay using a protocol adopted from previously published reports and manufacturer's instructions [9, 25, 26], expressed as the percentage of cell mortality relative to the control treatment (Figure 2). After 4–24 h of exposure to ZnO NPs (0.01–1.5 μg/mL), cell viability declined substantially in a concentration- and time-dependent manner; the declines were especially significant after 8 h of exposure to ZnO NPs ≥ 0.25 μg/mL (P < 0.05). The number of cell deaths among all these doses has been nearly 20% higher than the lower doses over the past 24 h. High cytotoxicity can be observed in cells treated with ZnO NPs when compared to control group. These results indicate that cell proliferation was inhibited significantly with increasing concentration of ZnO NPs.

Bottom Line: Both intracellular reactive oxygen species (ROS) and reduced glutathione (GSH) were examined by a microplate-reader method.Results showed that ZnO NPs (≥ 0.01 μg/mL) significantly inhibited proliferation (P < 0.05) and induced substantial apoptosis in LTEP-a-2 cells after 4 h of exposure.The intracellular ROS level rose up to 30-40% corresponding to significant depletion (approximately 70-80%) in GSH content in LTEP-a-2 cells (P < 0.05), suggesting that ZnO NPs induced apoptosis mainly through increased ROS production.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, 17 Chunhui Road, Laishan District, Yantai 264003, China ; University of Chinese Academy of Sciences, Beijing 100049, China.

ABSTRACT
Owing to the wide use of novel nanoparticles (NPs) such as zinc oxide (ZnO) in all aspects of life, toxicological research on ZnO NPs is receiving increasing attention in these days. In this study, the toxicity of ZnO NPs in a human pulmonary adenocarcinoma cell line LTEP-a-2 was tested in vitro. Log-phase cells were exposed to different levels of ZnO NPs for hours, followed by colorimetric cell viability assay using tetrazolium salt and cell survival rate assay using trypan blue dye. Cell morphological changes were observed by Giemsa staining and light microscopy. Apoptosis was detected by using fluorescence microscopy and caspase-3 activity assay. Both intracellular reactive oxygen species (ROS) and reduced glutathione (GSH) were examined by a microplate-reader method. Results showed that ZnO NPs (≥ 0.01 μg/mL) significantly inhibited proliferation (P < 0.05) and induced substantial apoptosis in LTEP-a-2 cells after 4 h of exposure. The intracellular ROS level rose up to 30-40% corresponding to significant depletion (approximately 70-80%) in GSH content in LTEP-a-2 cells (P < 0.05), suggesting that ZnO NPs induced apoptosis mainly through increased ROS production. This study elucidates the toxicological mechanism of ZnO NPs in human pulmonary adenocarcinoma cells and provides reference data for application of nanomaterials in the environment.

No MeSH data available.


Related in: MedlinePlus