Alterations in bronchoalveolar lavage constituents following urban pm10 intratracheal instillation in mice

Research into respirable air pollution particles (PM) and epidemiological studies have repeatedly found a positive correlation between the level of PM and increased morbidity and mortality rates in both adults and children. Urban PM differ with place of occurrence, meteorological conditions, physicochemical compositions, and the response of the bronchopulmonary apparatus. In the toxicology studies of inhaled or instilled agents, both the degree of an induced inflammatory response and the time course of recovery from or intensification of the process can be followed by analysis of the bronchoalveolar lavage (BAL). We investigated the alterations in BAL constituents following intratracheal instillation (by means of MicroSprayer® Aerosolizer- High Pressure Syringe) in mice of PM10 (100 μg in 100 μl of saline) collected in an urban setting in Milano from June until September 2008. The alterations in the enzymatic activity and in the oxidant status in BAL as well as in lung membrane and cytosol enriched fractions were compared with those observed in mice instilled with 100 μl of saline (controls). Mice were euthanized at 3 and 24 h and at 7 and 30 days postexposure, the trachea was cannulated and BAL collected. At 3 h and 24 h postexposure we found statistically significant increases in the TNFα level and in the percentage of polymorphonuclear cells (PMNs) in comparison with controls. The acute alteration in biochemical mediators of pulmonary inflammation observed in treated-mice may be correlated to the physicochemical composition of the urban PM10 collected in Milano from June to September 2008. Supported by Fondazione Cariplo.