Influence of concentrated ambient particles inhalation on periodontal chronic inflammatory process in mice

Vehicle and industrial emissions are the main responsible for the high pollutants concentration in urban centers. The gas exhaustion from internal combustion engines, for example, is composed by a mixture of gaseous compounds and particulate matter (PM), and, when inhaled, leads to several impacts on human health. The combustion process, naturally or by human action generated, provokes the release of high amounts of particulate matter, which accumulates in the atmosphere. Among the different types of particulate matter present in the air, the greatest concern of investigators are the fine particles (PM2.5), whose diameter is less than 2.5 µm and leads to local and systemic responses in those exposed to this category of particle, either in short-term or long-term exposures. Environmental levels of PM have been associated with increased morbidity, hospitalization and mortality from cardiovascular and respiratory diseases, as well as cancer and impaired cognition. PM associated with exhaustion and combustion, especially by anthropic actions, causes oxidative damage to DNA and lipids, immunoinflammatory process dysfunction, age-related chronic diseases acceleration, bone resorption and genotoxicity. The main purpose of this study was to evaluate the atmospheric particles concentration impact on the immunoinflammatory response and on alveolar bone loss, using a model of Escherichia coli LPS-induced periodontitis. For this purpose, we proposed the following specific objectives: to evaluate the impact of inhaling gases and particulate matter on healthy periodontal tissues and those submitted to periodontal disease. The experimental approach involved groups of mice exposed to polluted air or exposed to filtered air. From the beginning of the investigations, the animals were discovered to have periodontitis induced by bilateral injection of Escherichia coli 3 times per week, for 4 weeks. After euthanasia, lung and maxilla samples were collected. Descriptive histological analysis of these tissues demonstrated the occurrence of a chronic inflammatory process in the lungs of mice that were exposed to atmospheric pollutants, in addition to alterations in the pulmonary microstructure, affecting bronchioles and pulmonary alveoli. The results obtained also demonstrated the influence of the inhalation of particulate material on the periodontal inflammatory process and alveolar bone loss. Through the investigation proposed by the present study, it is concluded that the chronic breathing of fine particulate matter influences the occurrence of experimental periodontitis, enhancing the inflammatory effects in the periodontium. (AU)