Fig. 4. Effect of PM2.5 on the expression of tight junction mRNAs in air-liquid interface cultures established from nasal epithelial cells. After incubation with PM2.5 for 72 hours, relative mRNA expression of claudin-1 was significantly decreased and expression of ZO-1 and claudin-7 significantly increased in cultures treated with 100 μg/mL PM2.5, compared to control cultures (n = 10 each for the control and 50-μg/mL PM2.5-treated groups, n = 9 for the 100-μg/mL PM2.5-treated group).

PM2.5 with an aerodynamic diameter of less than 2.5 μm; mRNA, messenger RNA.

^*P < 0.05, ^†P < 0.01.