Compared to FRA exposed mice, Al2O3 NPs-exposed mice had higher concentrations of bronchoalveolar lavage fluid (BALF) interleukin (IL)-6 (a cytokine associated with decline in lung function [25]) and BALF IL-33 (a cytokine induces chronic airway inflammation [26, 27]) (Fig. 1b). This evidence concerns the gene IL6 and inflammation.