Fig. 2

Increased expression and activity of MMP-3 in the conditioned media of BEAS-2B cells and U937* macrophages exposed to Nano-CuO. BEAS-2B cells (a and c) and U937* macrophages (b and d) were exposed to 0.5 and 1 µg/mL of Nano-CuO for 12 h. After treatment, the conditioned media were collected. Cells without treatment were used as control. MMP-3 protein level in the conditioned media was detected by Western blot, while its activity was detected by β-casein zymography. Equal protein loading was verified by Coomassie Brilliant Blue staining. The activity of MMP-3 was also determined in the conditioned media from co-culture system (e). a, b, and e were the results of a single experiment, while c and d were normalized band densitometry readings averaged from three independent experiments. Data represent mean ± SE (n = 3). * Significant difference as compared to the control group, p < 0.05