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Effects of cholinergic hipofunction in lung mechanics and histopathology in an experimental model of lung inflammation induced by air pollution in mice

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Author(s):
Fernanda Paula Roncon Santana
Total Authors: 1
Document type: Master's Dissertation
Press: São Paulo.
Institution: Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD)
Defense date:
Examining board members:
Carla Máximo Prado; Luciana Chagas Caperuto; Iolanda de Fátima Lopes Calvo Tibério
Advisor: Carla Máximo Prado
Abstract

Diesel automotive engines are widely used in urban centers and its exhausts is considered a major environmental and toxic pollutant to human health. Because of their chemical characteristics, diesel particulate reaches more distal airways, which can induce and worsen pulmonary inflammation diseases such as bronchial asthma and pulmonary emphysema. It has recently been demonstrated by our group that the cholinergic anti-inflammatory system is an important modulator of lung inflammation. Thus, the aim of this study was to evaluate whether the cholinergic deficiency induced by reduced expression of the vesicular acetylcholine transporter protein (VAChT) interferes in pulmonary function and histopathological changes in an experimental model of repeated diesel exhaust particles (DEP) instillation. To this end, male mice with reduction in VAChT were used, divided according to genotyping for wild-type (WT) and knock-down for VAChT (KD), and submitted to DEP exposure protocol, which consisted in intranasal instillation of 10 ?L of DEP in a concentration of 3 mg/mL for 30 days (5x per week). Control groups received saline following the same protocol. We evaluated: respiratory mechanics, inflammation in broncoalveolar lavage (BAL), immunohistochemistry and ELISA for cytokine detection, pulmonary extracellular matrix remodeling and bronchial and nasal epithelium mucus. Our results showed that WT animals submitted to DEP protocol showed increased macrophages in BAL and mononuclear cells in peripheral blood, increased expression of TNF-alfa, IL-4, IL-6 and IL-13 in lung tissue, collagen fibers remodeling in lung parenchyma and increase in neutral mucus production in the airways when compared to the saline exposed animals. These changes were associated with worse lung function. The cholinergic deficiency in the animals instilled with DEP induced an increase in BAL neutrophils and lymphocytes and granulocytes in the peripheral blood, in the expression of IL-4 and TNF-alfa and in lung elastic fibers content in alveolar septa. In addition, there was an increase in acid mucus in nasal epithelium. These data suggest that, at least in part, cholinergic system interferes with pulmonary inflammation induced by DEP exposures, since animals with cholinergic deficiency exhibit some inflammatory alterations which are not observed or observed on a smaller scale in wild-type animals (AU)

FAPESP's process: 11/15817-7 - CHOLINERGIC HYPOFUNCTION EFFECTS IN THE MECHANICAL AND LUNG HISTOPATHOLOGY IN AN EXPERIMENTAL MODEL OF LUNG INFLAMMATION INDUCED BY AIR POLLUTANT INSTILLATION IN MICE
Grantee:Fernanda Paula Roncon Santana Novelli
Support Opportunities: Scholarships in Brazil - Master