Fig. 3.

Inflammatory cytokine expression in AECs stimulated with LPS in weakly acidic media for 16 h. AECs were stimulated with 5 μg/ml LPS in media adjusted to pH6.5 – pH5.5 with HCl for 16 h (n = 3). Normal, unadjusted BEGM is pH7.4; this was used as a control to show basal IL-6 and IL-8 expression. LPS stimulation at pH7.4 was used as a control for normal AEC response to LPS. Brefeldin A (BA) was used with LPS as a positive control for intracellular protein retention. a IL-6 and IL-8 mRNA expression was measured by qPCR. Fold change is related to pH7.4 control. b Cytosolic IL-6 and IL-8 protein was measured in pg/ml by ELISA of whole cell lysates and was normalised to total protein concentration, measured in μg/ml by BCA assay. Cytosolic cytokine was calculated in ng. c Secretion of IL-6 and IL-8 proteins was measured in pg/ml by ELISA of cell supernatants. d Cell viability was measured by MTT assay. (n = 3) All test pH conditions were compared to pH7.4 + LPS for statistical analysis. Values presented are mean ± SEM *p < 0.05, **p < 0.01