Pulmonary toxicity of dust generated during weaving of carpets

Toxic effect of carpet dust on the biochemical indices and histological structure of the lung in rats: the potential role of cytochrome P450 2E1 and extracellular signal-regulated kinase/mitogen-activated protein kinase pathways

Background: Carpet dust exposure in the carpet industry causes various respiratory hazards that lead to permanent loss of lung function. This study investigated the potentially toxic effects of knotted and tufted carpet dust on rat lungs and the possible involvement of cytochrome P450 2E1 (CYP2E1) and extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) pathways in the induced toxicity, as well as histological changes in the lung induced by carpet dust.Methods: This study divided 48 adult rats into six groups: group I was the control group, group II (vehicle group) received phosphate buffer saline (50 µL/rat), groups III and IV received knotted dust (2.5 and 5 mg/kg, respectively), and groups V and VI received tufted dust (2.5 and 5 mg/kg, respectively). All treatments were intranasally administered once a day for 7 days.Results: Both dust types significantly decreased the lung content of GSH compared with the control. Significantly elevated malondialdehyde (MDA) and nitric oxide (NO) lung contents were observed with an increased CYP2E1, interleukin (IL)-6, nuclear factor kappa B (NF-κβ), and ERK/MAPK. The histological lung structure was moderately affected with a moderately increased number of CD68-positive macrophages in the lung parenchyma of knotted dust-exposed rats, whereas tufted dust exposure severely affected the lung tissue with significantly increased CD68-positive macrophages.Conclusions: Carpet dust exposure could induce oxidative stress and inflammatory response in the lung tissue via induction of CYP2E1 that stimulates ERK/MAPK signalling pathway proteins, resulting in elevated MDA, NO and IL-6 levels in the lung tissue with suppressed GSH content. Tufted dust could possess a more toxic response than knotted ones.

Evaluation of cytotoxic, genotoxic and inflammatory responses of micro- and nano-particles of granite on human lung fibroblast cell IMR-90

Occupational exposure of granite workers is well known to cause lung impairment and silicosis. Toxicological profiles of different size particles of granite dust, however, are not yet understood. Present evaluation of micro- and nano-particles of granite dust as on human lung fibroblast cells IMR-90, revealed that their toxic effects were dose-dependent, and nanoparticles in general were more toxic. In this study we first demonstrated that nanoparticles caused oxidative stress, inflammatory response and genotoxicity, as seen by nearly 2 fold induction of ROS and LPO, mRNA levels of TNF-α and IL-1β, and induction in micronuclei formation. All these were significantly higher when compared with the effect of micro particles. Thus, the study suggests that separate health safety standards would be required for granite particles of different sizes.

New approach to environmental tobacco smoke exposure and its relation to reemission processes

Indoor air quality is one of the factors that determine human well-being and health. Being aware of this fact, it is essential to identify the origin, kind, mechanism, and effects of harmful substances contained in the air. The issue concerning the contents and primary emission of these substances from building materials and interior furnishings is well known. Adverse effects of environmental tobacco smoke (ETS), including exposure of passive smokers, are also very well documented. To the contrary, reports on secondary and indirect emissions, especially those focused on mechanisms by which pollution is "transferred" by materials used in interior furnishings are very rare. Textiles are used in a great variety of ways as functional and decorative materials. These materials in general, and textile floor coverings in particular, are extensively utilized in fitting apartments, public buildings, and transport means. Studies on this aspect of the role played by textile materials in ETS exposure have been only fragmentary documented.

Cytotoxic effect and role of exogenous antioxidants in carpet dust mediated toxicity in rat hepatocytes in vitro

Carpet industries bear a great deal of economic and commercial significance in India. In order to safe guard the workers against the health hazards caused by dust in their occupational environment; it necessitates studying the biological importance of these dusts. The present study was designed to investigate the toxicity of carpet dust (knotted and tuffted) on isolated rat hepatocytes. The hepatocytes were isolated by collagenase perfusion method and cells were incubated with different concentration of carpet dust (100-5000 microg/10(6) cells) with various time (30-180 min) intervals. An exogenous antioxidant vitamin-E also used to find out the role of antioxidants and free radical production in carpet dust mediated toxicity. Cell viability by trypan blue exclusion and leakage of enzyme lactate dehydrogenase (LDH) were determined. Reduced glutathione (GSH), formation of thiobarbituric acid reactive substance (TBARS) were also measured. A significant decrease in the cell viability was observed after 60, 180 min upon incubation with tuffted carpet dust, while knotted carpet dust caused a significant decrease in the viability after 180 min. LDH leakage was parallel to the cell viability. Thiobarbituric acid reactive substance was significantly increased at 30 and 60 min with carpet dust treated hepatocytes. Dust at 1000 and 5000 microg dose level showed significantly increased formation of TBARS at 30 min incubation. However, when hepatocytes were co-incubated with carpet dust and Vit-E (10, 15 microM), a significant decrease in LDH release and TBARS production was observed while 15 microM Vit-E showed an enhanced protection than 10 microM Vit-E treated hepatocytes. The effect of carpet dust on cell viability, LDH leakage, TBARS production, GSH depletion was time and dose-dependent. Moreover, we observed that tuffted carpet dust causes greater effect than knotted one on the above mentioned parameters. Our studies also revealed that Vit-E in culture media diminishes the carpet dust mediated toxicity.

Differential responses of rat alveolar macrophages to carpet dust in vitro

Epidemiological studies of workers in carpet weaving units in carpet industries have shown a direct relation between the concentration of carpet dust in the air and respiratory symptoms. To predict the health risk of carpet weavers, this preliminary study was conducted to evaluate the toxic potential of different types of workplace dust by using alveolar macrophages (AMs). Several parameters were observed for cytotoxicity such as cell viability, the release of lactate dehydrogenase (LDH) in rat AMs treated with different concentration of carpet dust and haemolytic potential of erythrocytes. In addition, reactive oxygen/nitrogen species-inducing effects of carpet dust were assessed by nitric oxide (NO), reduced glutathione (GSH) release and hydrogen peroxide (H2O2) generation in AMs. Results of cell viability and hemolytic assay showed a direct correlation between increasing the dust concentration with enhancing the toxic effect. Knotted and tufted carpet dust increases the release of LDH, NO, GSH and H2O2 production with increasing dust concentration. Present observations have revealed that dusts collected from tufted carpet weaving units exhibited more toxicity to AMs than knotted carpet dust. These data further suggest that injurious effects of carpet dust to AMs could pave a way to evaluate the toxic potential of the different types of workplace dusts and component(s) involved in it.