Single-Walled Carbon Nanotubes Attenuate Cytotoxic and Oxidative Stress Response of Pb in Human Lung Epithelial (A549) Cells

Abstract

Combined exposure of single-walled carbon nanotubes (SWCNTs) and trace metal lead (Pb) in ambient air is unavoidable. Most of the previous studies on the toxicity of SWCNTs and Pb have been conducted individually. There is a scarcity of information on the combined toxicity of SWCNTs and Pb in human cells. This work was designed to explore the combined effects of SWCNTs and Pb in human lung epithelial (A549) cells. SWCNTs were prepared through the plasma-enhanced vapor deposition technique. Prepared SWCNTs were characterized by x-ray diffraction, x-ray photoelectron spectroscopy, scanning electron microscopy, and dynamic light scattering. We observed that SWCNTs up to a concentration of 100 µg/mL was safe, while Pb induced dose-dependent (5–100 µg/mL) cytotoxicity in A549 cells. Importantly, cytotoxicity, cell cycle arrest, mitochondrial membrane potential depletion, lipid peroxidation, and induction of caspase-3 and -9 enzymes following Pb exposure (50 µg/mL for 24 h) were efficiently attenuated by the co-exposure of SWCNTs (10 µg/mL for 24 h). Furthermore, generation of Pb-induced pro-oxidants (reactive oxygen species and hydrogen peroxide) and the reduction of antioxidants (antioxidant enzymes and glutathione) were also mitigated by the co-exposure of SWCNTs. Inductively coupled plasma-mass spectrometry results suggest that the adsorption of Pb on the surface of SWCNTs could attenuate the bioavailability and toxicity of Pb in A549 cells. Our data warrant further research on the combined effects of SWCNTs and Pb in animal models.

Combined effects of nanoparticles and other environmental contaminants on human health - an issue often overlooked

“…Azari et al also concluded from two studies that benzo[a]pyrene (B[a]P) adsorbed on multi-walled carbon nanotubes, resulting in a decrease of the bioavailability of B[a]P and consequently an attenuation of its adverse effects (Azari et al, 2019;Rezazadeh Azari et al, 2019). Similar results were observed with single-walled carbon nanotubes that can adsorb Pb at their surface leading to a decreased bioavailability and toxicity of Pb (Ahamed et al, 2020b). Furthermore, we should consider carefully the kinetic aspect in these studies as the bioavailability of the co-pollutant depends on its desorption rate and effects may not be observed if too early time points are considered (effects may just be delayed).…”

Polish and New Zealand Propolis as Sources of Antioxidant Compounds Inhibit Glioblastoma (T98G, LN-18) Cell Lines and Astrocytoma Cells Derived from Patient

“…Therefore, the content of these elements in propolis should be constantly monitored. Studies by Ahamed et al [ 30 ] confirm that Pb can influence of viability, cell cycle, lipid peroxidation, and caspase activation in human lung epithelial (A549) cells. However, it should be noted that propolis is a product that contains a number of compounds with antioxidant potential.…”

“…The cells were cultured as follows: in a humidified incubator at 37 • C and 5% CO 2 atmosphere; in MEM or DMEM supplemented with 10% heat inactivated FBS; with 100 U/mL penicillin and 0.1 mg/mL streptomycin. Doses of propolis (10,20,30,50, 100 µg/mL) were selected in our previous experiments [11]. Cells at a density of 1 × 105 cells/mL were seeded onto 96-well plates at a volume of 200 µL per well and grown for 22 h at 37 • C in a humidified 5% CO 2 incubator.…”

Lung Toxicity and Molecular Mechanisms of Lead-Based Perovskite Nanoparticles in the Respiratory System

“…36 Previous studies have indicated that Pb exposure cause cell viability decrease, ROS production, lipid peroxidation, apoptosis, and antioxidant exhaustion in human lung epithelial cells. 37 However, the available data for comprehensively evaluating the adverse impacts of Pb-PNPs both in vitro and in vivo are insufficient. Moreover, there are no reports on the lung toxicity effects of Pb-PNPs or the underlying biological mechanisms in these conditions.…”