Pulmonary function and histological impairment in mice after acute exposure to aluminum dust

Abstract

Along the aluminum refining process, alumina (Al₂O₃) constitutes the main source of dust. Although aluminum refinery workers present respiratory symptoms with lung functional changes, no conclusive data about lung function impairment after alumina exposure has been so far reported. We examined the pulmonary alterations of exposure to material collected in an aluminum refinery in Brazil. BALB/c mice were exposed in a whole-body chamber for 1 h to either saline (CTRL, n = 11) or to a suspension (in saline) of 8 mg/m³ of the dust (ALUM, n = 11) both delivered by an ultrasonic nebulizer. Twenty-four hours after exposure lung mechanics were measured by the end-inflation method. Lungs were prepared for histology. ALUM showed significantly higher static elastance (34.61 ± 5.76 cmH₂O/mL), elastic component of viscoelasticity (8.16 ± 1.20 cmH₂O/mL), pressure used to overcome the resistive component of viscoelasticity (1.62 ± 0.24 cmH₂O), and total resistive pressure (2.21 ± 0.49 cmH₂O) than CTRL (27.95 ± 3.63 cmH₂O/mL, 6.12 ± 0.99 cmH₂O/mL, 1.23 ± 0.19 cmH₂O, and 1.68 ± 0.23 cmH₂O, respectively). ALUM also presented significantly higher fraction area of alveolar collapse (69.7 ± 1.2%) and influx of polymorphonuclear cells (27.5 ± 1.1%) in lung parenchyma than CTRL (27.2 ± 1.1% and 14.6 ± 0.7%, respectively). The composition analysis of the particulate matter showed high concentrations of aluminum. For the first time it was demonstrated in an experimental model that an acute exposure to dust collected in an aluminum producing facility impaired lung mechanics that could be associated with inflammation.

Keywords::

• Alumina
• particulate matter
• air pollution
• lung mechanics
• inflammation

Acknowledgements

The authors are grateful to Joao Luiz Coelho Rosas Alves and Antonio Carlos de Souza Quaresma for their skillful technical assistance.

Declaration of Interest

This study was supported by: Centers of Excellence Program (PRONEX/FAPERJ), Brazilian Council for Scientific and Technological Development (CNPq), Carlos Chagas Filho Rio de Janeiro State Research Supporting Foundation (FAPERJ).