Inhibition of matrix metalloproteinase-9 secretion by dimethyl sulfoxide and cyclic adenosine monophosphate in human monocytes

Figure 2 Dimethyl sulfoxide inhibits lipopolysaccharide-induced matrix-metalloproteinase-9 in a dose-dependent fashion. A: SDS-PAGE/immunoblot of cell supernatants; B: Densitometry of Panel A. Each data bar is the average ± standard error for three independent densitometry measurements. Data were fit to a nonlinear inhibition equation, which produced an IC₅₀ of 0.64%; and C: Tumor necrosis factor α levels were determined in cell supernatants by enzyme-linked immuno sorbent assay and each data bar is the average ± standard error for three independent measurements. THP-1 monocytes were treated with a concentration range of dimethyl sulfoxide (0.1%-1%) followed by lipopolysaccharide (1 μg/mL) for 72 h. Cells were collected, centrifuged at 500 g for 10 min and supernatant assessed for (A) matrix-metalloproteinase-9 and (C) tumor necrosis factor α. DMSO: Dimethyl sulfoxide; MMP-9: Matrix-metalloproteinase-9; TNFα: Tumor necrosis factor α.