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

Figure 1 Dimethyl sulfoxide inhibits lipopolysaccharide-induced matrix-metalloproteinase-9, but not tumor necrosis factor α, secretion. THP-1 monocytes were treated in the absence or presence of dimethyl sulfoxide (2%) and with either sterile water or lipopolysaccharide (0.1 μg/mL or 1 μg/mL) for 72 h. A: Cells were collected, centrifuged at 500 g for 10 min and supernatant assessed for matrix-metalloproteinase-9 (MMP-9), SDS-PAGE/immunoblot of cell supernatants. Lane 1 is an MMP-9 Western blotting standard (10 μL); B: Densitometry of Panel A. Each data bar is the average ± standard error for three independent densitometry measurements; and C: TNFα levels were determined in cell supernatants by enzyme-linked immuno sorbent assay and each data bar is the average ± std error for three independent measurements, Tumor necrosis factor α (TNFα). Statistical differences (^aP < 0.05 or ^bP < 0.01) for 0.1 μg/mL or 1 μg/mL lipopolysaccharide and dimethyl sulfoxide inhibition of MMP-9 or TNFα secretion are shown. DMSO: Dimethyl sulfoxide; LPS: Lipopolysaccharide; MMP-9: Matrix-metalloproteinase-9; TNFα: Tumor necrosis factor α.