Abstract
A number of studies have shown variable grades of cytotoxicity and genotoxicity in in vitro cell cultures, laboratory animals and humans when directly exposed to particle debris generated from tires. However, no study has compared the effects of particles generated from passenger tires with the effects of particles from truck tires. The aim of this study was to investigate and relate the cyto- and genotoxic effects of different types of particles (PP, passenger tire particles vs. TP, truck tire particles) in vitro using the phagocytic cell line RAW 264.7 (mouse leukaemic monocyte macrophage cell line). The viability of RAW 264.7 cells was determined by the 3- (4,5-dimethylthiazol-2-yl) -5- (3-carboxymethoxyphenyl) -2- (4-sulfophenyl) -2H-tetrazolium (MTS) assay following exposure for 4, 24 and 48 hours to different particle concentrations (10 μg / ml, 25 μg / ml, 50 μg / ml, 100 μg / ml). The effects of particles of passenger and truck tires on cell proliferation and genotoxicity were evaluated by means of the cytokinesis-block micronucleus (CBMN) assay following exposure for 24 hours to different particle concentrations (10 μg / ml, 25 μg / ml, 50 μg / ml, 100 μg / ml). In MTS assay, after 24 hours, it was found that PP induced a 30% decrease in metabolic activity at a concentration of 10 μg/ml, while TP caused reductions of 20% and 10% at concentrations of 10 μg/ml and 50 μg/ml, respectively. At 48 hours after the treatments, we observed increased metabolic activity at 50 μg/ml and 100 μg/ml for the PP while only at 50 μg/ml for the TP. The CBMN assay showed a significant increase in the number of micronuclei in the cells incubated with PP in all experimental conditions, while the cells treated with TP showed a meaningful increase only at 10 μg /ml. We utilized the TNF-α ELISA mouse test to detect the production of tumour necrosis factor-alpha (TNF-α) in RAW 264.7 cells. The effect of passenger and truck particles on TNF-α release was evaluated following exposure for 4 and 24 hours.After 4 hours of incubation, the cells treated with PP and TP at 100 μg / ml showed a slight but significant increase in TNF-α release, while there was a significant increase in the release of TNF-α after 24 hours of incubation with both tire samples in the cells treated with 50 and 100 μg / ml PP. The data obtained show a higher cytotoxic, clastogenic/genotoxic and inflammatory effects of passenger compared to the truck tire particles.
Highlights
Air pollution is one of the most urgent environmental problems affecting human health
It has been observed that the size of the particulate matter (PM) and the qualitative properties, such as shape and chemical composition, influence the ability of tire rubber particles to induce an inflammatory response in exposed human subjects and cultured macrophages
Tire particles may exert harmful effects on health and/or the environment, attributable to the various components of the rubber used for the production of Passenger and truck tires particles and geno-cyto toxicity on RAW 264.7 macrophages tires, to metals found in formulation mixtures that come into contact with our respiratory system or are deposited primarily onto the road surface [7,8, 18,19,20]
Summary
Air pollution is one of the most urgent environmental problems affecting human health. Several studies have been conducted on air pollution and its direct and indirect consequences on human health and ecosystems. In addition to such well-known air pollutants as ozone, sulfur oxides, nitrogen oxides, and volatile organic compounds (VOC), atmospheric particulate matter (PM) is a notable air pollutant. Specific epidemiological studies have indicated a link between high concentrations of atmospheric particles and increased admissions into hospitals and mortality rates, thereby demonstrating the negative effects on human health of short- and long-term exposure to environmental PM [1,2]. The adverse health effects of airborne particles include respiratory morbidity, which is manifested by reduced pulmonary function, cardiovascular morbidity, cancer, and death [3]
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