Oxidative Stress, Calcium Homeostasis, and Altered Gene Expression in Human Lung Epithelial Cells Exposed to ZnO Nanoparticles

Abstract

The influence of 20 nm ZnO nanoparticles on cytotoxicity, oxidative stress, intracellular calcium homeostasis, and gene expression was studied in human bronchial epithelial cells (BEAS-2B). ZnO caused a concentration- and time-dependent cytotoxicity while elevating oxidative stress and causing membrane damage (cellular LDH release). There was a remarkably steep relationship between concentration and toxicity at concentrations from 5 to 10 μg/ml. Cytotoxicity was completely abolished by the antioxidant N-acetylcysteine (NAC). Exposure to ZnO also increased intracellular calcium levels ([Ca2+]in) in a concentration- and time-dependent manner that was partially attenuated by NAC. Nifedipine, a calcium channel blocker, partially attenuated the elevated [Ca2+]in, indicating that some of the excess [Ca2+]in is a result of influx from outside the cell. The relationships between oxidative stress, [Ca2+]in, and cytotoxicity are discussed. Exposure to a sublethal concentration of ZnO increased the expression of four genes that are involved in apoptosis and oxidative stress responses BNIP, PRDX3, PRNP, and TXRND1, by at least 2.5-fold. Thus, ZnO alters transcriptional regulation in BEAS-2B cells.

Department(s)

Biological Sciences

Sponsor(s)

Missouri University of Science and Technology

International Standard Serial Number (ISSN)

0887-2333

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2010 Elsevier, All rights reserved.

Publication Date

01 Feb 2010

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