Cigarette smoke extract induces cytotoxicity on human nasal epithelial cells

Background: The nasal mucosa is the first area to be exposed to a variety of inhaled toxins. Among various inhaled toxins, cigarette smoke is the most common one and is associated with several nasal and sinus disorders. Methods: To evaluate the cytotoxic effects of cigarette smoke, primary human nasal epithelial cells were cultured in various concentrations of cigarette smoke extract (CSE) for various times. Cell viability was evaluated by WST-1 (4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate) assay. Morphological findings were observed under the light microscope and the electron microscope. Annexin-V stain was used for the detection of apoptosis. Results: Using the WST-1 assay, CSE reduced cell viability in a time- and concentration-dependant manner. CSE-treated cells showed initial membrane blebbing followed by vesicle formation without apoptotic body formation or cell membrane rupture. Cells were stained with annexin-V but without propidium iodide under a fluorescence microscope. TUNEL (terminal deoxynucleotidyltransferase-media fed dUPT nick end labeling) stain was positive in CSE-treated cells. Conclusion: CSE induces cytotoxicity on primary human nasal epithelial cells and the morphological findings closely mimic partition apoptosis.