Fig. 10
The expression levels and enzymatic activities of MMP-2 and MMP-9 in MH-S cells exposed to PM2.5 with/without high glucose pretreatment. The cells were treated with 25 or 50 μg/mL of PM2.5 for 3, 6, 12, and 24 h (a, b, g) or 24 h (c-f, h) with/without 30 mM of glucose pretreatment for 18 days. The cells treated with physiological saline were used as control. a-d The mRNA expressions of MMP-2 and MMP-9 were determined by RT-qPCR and normalized to the β-actin expression in the same sample. e, f The protein levels of MMP-2 and MMP-9 in cell culture media were determined by ELISA. Data are shown as mean ± SEM (n = 3). * p < 0.05 vs. control; # p < 0.05 vs. group with the same dose of PM2.5 treatment only. g, h The enzymatic activities of MMP-2 and MMP-9 in the cell culture media were determined by gelatin zymography assay