Effect of PM2.5 mediated oxidative stress on the innate immune cellular response of Der p1 treated human bronchial epithelial cells.

OBJECTIVE: To investigate the effect of stimulation of Human Bronchial Epithelial Cells (HBEC) by Der p1 and PM2.5 on the expression of innate immune cell factors to find new therapeutic targets for treatment of bronchial asthma.

MATERIALS AND METHODS: The Der p1 antigen exposure model in the HEBC line, 16HBE-14o, was established in vitro. PM2.5 at a concentration of 50 µM/cm2, was added to these cells for 0.5 h, 1 h, 2 h and 3 h. Cells were treated with the following reagents for the indicated times: 300 ng/mL Der p1 for 21 h, 50 µM/cm2 PM2.5 for 3 h, 10 mM Nac for 3 h and PM2.5 contamination for 3 h. The experiment was divided into five groups: control (group A), Der p1 exposure group (group B), PM2.5 treated group (group C), PM2.5+Der p1 exposure group (group D), Nac+PM2.5+Der p1 exposure group (group E). ELISA method was adopted to test the expression levels of malondialdehyde, IL-25, IL-33 and thymic stromal lymphopoietin (TSLP), and Real-time RT-PCT was used to measure IL-25, IL-33 and TSLP mRNA.

RESULTS: The protein and mRNA levels of malondialdehyde, IL-25, IL-33 and TSLP in group D were significantly higher than those in the other groups, while the protein and mRNA levels of malondialdehyde, IL-25, IL-33 and TSLP in group E were significantly lower than those in group D (p<0.05).

CONCLUSIONS: PM2.5 can enhance the Der p1 antigen-induced HBEC innate immune response through the expression of IL-25, IL-33 and TSLP, which may exacerbate the occurrence rate of bronchial asthma.