Fig. 4

Effects of p-SPAK on the expressions of claudin-18 and barrier function in MLE-12 cells exposed to hyperoxia. a Effects of exposure duration on expressions of claudin-18 in MLE-12 cells determined by western blot analysis (n = 4). *p < 0.05 versus 0 h. b, c Effects of SPAK-KD on expressions of claudin-18 in MLE-12 cells determined by western blot analysis and mRNA levels (n = 4). *p < 0.05 versus normoxia control; ^#p < 0.05 versus hyperoxia control. d Transepithelial electrical resistance of MLE-12 cells measured by ECIS (n = 4). e Barrier resistance (Rb) of MLE-12 cells measured by ECIS (n = 4). *p < 0.05 versus 0 h control; ^#p < 0.05 versus 24 h control; ^&p < 0.05 versus 48 h control. f Paracellular permeability assay using MLE-12 cells cultured with FITC-dextran (n = 5). *p < 0.05 versus normoxia control; ^#p < 0.05 versus hyperoxia control. SPAK-KD SPAK knock-down. Data are expressed as the means ± SD