Abstract
In urban centres, diesel exhaust particles (DEP) are the most toxic pollutant released from automotive engines, affecting pulmonary health. The aim of this study was to investigate the effects of a chronic period of exposure to DEP (three months) in healthy mice (Yoshizaki et al., 2010) studying whether chronic, near-ambient levels of DEP exposure could induce changes in the lung parenchyma structure and in the profile of inflammatory cells. Male Balb/c mice were divided into two groups: 1) nasal instillation of 10 μL of saline (n=8) (control group) and 2) nasal instillation of 30 μg/10 μL of DEP (n=9) (DEP group). Nasal instillations were performed five days a week for three months. Lung parenchyma was evaluated by quantifying the mean airspace chord lengths (Lm) by morphometry (point counting). T lymphocytes total (CD3) and macrophages (Mac-2) densities were analyzed by immunohistochemistry. DEP exposure induced increase of CD3 T lymphocytes in DEP when compared to Control (p=0.028); no statistical difference was found in macrophages density. The Lm was larger in DEP animals than controls (p=0.018). These findings indicate that chronic, near-ambient levels of DEP exposure can cause alveolar enlargement and T- lymphocytes recruitment, providing a biological link between DEP exposure and the emphysema.
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