Abstract
Residual oil fly ash (ROFA) is a common pollutant in areas where oil is burned. This particulate matter (PM) with a broad distribution of particle diameters can be inhaled by human beings and putatively damage their respiratory system. Although some studies deal with cultured cells, animals, and even epidemiological issues, so far a comprehensive analysis of respiratory outcomes as a function of the time elapsed after exposure to a low dose of ROFA is wanted. Thus, we aimed to investigate the time course of mechanical, histological, and inflammatory lung changes, as well as neutrophils in the blood, in mice exposed to ROFA until 5 days after exposure. BALB/c mice (25 ± 5 g) were randomly divided into 7 groups and intranasally instilled with either 10 μL of sterile saline solution (0.9% NaCl, CTRL) or ROFA (0.2 μg in 10 μL of saline solution). Pulmonary mechanics, histology (normal and collapsed alveoli, mononuclear and polymorphonuclear cells, and ultrastructure), neutrophils (in blood and bronchoalveolar lavage fluid) were determined at 6 h in CTRL and at 6, 24, 48, 72, 96, and 120 h after ROFA exposure. ROFA contained metal elements, especially iron, polycyclic aromatic hydrocarbons (PAHs), and organochlorines. Lung resistive pressure augmented early (6 h) in the course of lung injury and other mechanical, histological and inflammatory parameters increased at 24 h, returning to control values at 120 h. Blood neutrophilia was present only at 24 and 48 h after exposure. Swelling of endothelial cells with adherent neutrophils was detected after ROFA instillation. No neutrophils were present in the lavage fluid. In conclusion, the exposure to ROFA, even in low doses, induced early changes in pulmonary mechanics, lung histology and accumulation of neutrophils in blood of mice that lasted for 4 days and disappeared spontaneously.
Highlights
Many studies associate events of urban air pollution with significant health effects on the exposed population, including morbidity and mortality due to cardiopulmonary diseases or lung cancer (Dominici et al, 2006; Fajersztajn et al, 2013)
It should be stressed that around 7.6% of Residual oil fly ash (ROFA) particles presented an average diameter smaller than 10 μm, and about 2.1% were smaller than 2.5 μm (Avila et al, 2011)
ROFA analysis showed the presence of metal elements, such as copper, cadmium, chromium, nickel, manganese, lead, zinc and mainly iron (Table 1), and polycyclic aromatic hydrocarbons (PAHs), such as naphthalene, acenaphthylene, fluorene, acenaphthene, antracene, flouranthene, phyrene, benzo[k]fluorantene, benzo[ghi]peryle (Table 2)
Summary
Many studies associate events of urban air pollution with significant health effects on the exposed population, including morbidity and mortality due to cardiopulmonary diseases or lung cancer (Dominici et al, 2006; Fajersztajn et al, 2013). These outcomes have been observed even at pollution levels below current national and international ambient air quality health standards (Lin et al, 1999). Long-term mice exposure to traffic-derived particulate matter (PM) yielded worse pulmonary function, bronchial/alveolar lesion, lung macrophage influx, and oxidative stress (Mazzoli-Rocha et al, 2014), secretory cell hyperplasia and ultrastructural ciliary alterations of the airway epithelium (Saldiva et al, 1992a), compromised respiratory defenses (Lemos et al, 1994), as well as cardiopulmonary oxidative damage (Damiani et al, 2012)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
