Figure 4.

Histone deacetylase inhibitors repress matrix metalloproteinase (MMP) protein expression and activity. Cells were starved of serum for 24 hours before stimulation with I/O, a combination of IL-1α (5 ng/ml) and oncostatin M (10 ng/ml), for 24 hours in the absence or presence of trichostatin A (TSA) (500 ng/ml) or sodium butyrate (NaBy) (10 mM). Conditioned media were subjected to western blot analysis using a rabbit anti-(human MMP-1) antibody or a sheep anti-(human MMP-13) antibody or gelatin zymography, as described in Materials and methods.