VITOR BRITO DA SILVA
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- Chronic exposure of diesel exhaust particles induces alveolar enlargement in mice(2015) YOSHIZAKI, Kelly; BRITO, Jose Mara; MORIYA, Henrique T.; TOLEDO, Alessandra C.; FERZILAN, Sandra; OLIVEIRA, Ana Paula Ligeiro de; MACHADO, Isabel D.; FARSKY, Sandra H. P.; SILVA, Luiz F. F.; MARTINS, Milton A.; SALDIVA, Paulo H. N.; MAUAD, Thais; MACCHIONE, MariangelaBackground: Diesel exhaust particles (DEPs) are deposited into the respiratory tract and are thought to be a risk factor for the development of diseases of the respiratory system. In healthy individuals, the timing and mechanisms of respiratory tract injuries caused by chronic exposure to air pollution remain to be clarified. Methods: We evaluated the effects of chronic exposure to DEP at doses below those found in a typical bus corridor in Sao Paulo (150 mu g/m(3)). Male BALB/c mice were divided into mice receiving a nasal instillation: saline (saline; n = 30) and 30 mu g/10 mu L of DEP (DEP; n = 30). Nasal instillations were performed five days a week, over a period of 90 days. Bronchoalveolar lavage (BAL) was performed, and the concentrations of interleukin (IL)-4, IL-10, IL-13 and interferon-gamma (INF-gamma) were determined by ELISA-immunoassay. Assessment of respiratory mechanics was performed. The gene expression of Muc5ac in lung was evaluated by RT-PCR. The presence of IL-13, MAC2+ macrophages, CD3+, CD4+, CD8+ T cells and CD20+ B cells in tissues was analysed by immunohistochemistry. Bronchial thickness and the collagen/elastic fibers density were evaluated by morphometry. We measured the mean linear intercept (Lm), a measure of alveolar distension, and the mean airspace diameter (D0) and statistical distribution (D2). Results: DEP decreased IFN-gamma levels in BAL (p = 0.03), but did not significantly alter IL-4, IL-10 and IL-13 levels. MAC2+ macrophage, CD4+ T cell and CD20+ B cell numbers were not altered; however, numbers of CD3+ T cells (p <= 0.001) and CD8+ T cells (p <= 0.001) increased in the parenchyma. Although IL-13 (p = 0.008) expression decreased in the bronchiolar epithelium, Muc5ac gene expression was not altered in the lung of DEP-exposed animals. Although respiratory mechanics, elastic and collagen density were not modified, the mean linear intercept (Lm) was increased in the DEP-exposed animals (p <= 0.001), and the index D2 was statistically different (p = 0.038) from the control animals. Conclusion: Our data suggest that nasal instillation of low doses of DEP over a period of 90 days results in alveolar enlargement in the pulmonary parenchyma of healthy mice.
- Organic and Inorganic Fractions of Diesel Exhaust Particles Produce Changes in Mucin Profile of Mouse Trachea Explants(2015) SERIANI, Robson; JUNQUEIRA, Mara S.; TOLEDO, Alessandra C.; CORREA, Aristides T.; SILVA, Luiz F. F.; MARTINS, Milton A.; SALDIVA, Paulo H. N.; MAUAD, Thais; MACCHIONE, MariangelaDiesel exhaust particles (DEP) contain organic and inorganic elements that produce damage to the respiratory epithelium. The aim of this study was to determine the mucus profile of tracheal explants exposed to either crude diesel exhaust particles (DEP) or DEP treated with nitric acid (DEP/NA), with hexane (DEP/HEX), or with methanol (DEP/MET) at concentrations of 50 and 100 mu g/ml for 30 and 60 min. Tracheal explants were subjected to morphometric analyses to study acidic (AB+), neutral (PAS+), and mixed (AB+/PAS+) mucus production and vacuolization (V). Incubation with 50 mu g/ml crude DEP resulted in a rise in acid mucus production, an increase in vacuolization at 30 min, and reduction in neutral mucus at 30 and 60 min. Tracheas exposed to DEP/MET at 50 mu g/ml for 30 or 60 min resulted in a significant decrease in neutral mucus production and an elevation in acid mucus production. DEP/HEX increased vacuolization at both 50 and 100 mu g/ml at 30 and 60 min of exposure. Treatment with 50 mu g/ml for 30 or 60 min significantly elevated mixed mucus levels. These results suggest that DEP appear to be more toxic when administered in combination with HEX or MET. DEP/MET modified the mucus profile of the epithelium, while DEP/HEX altered mucus extrusion, and these responses might be due to bioavailability of individual elements in DEP fractions.