Effect of colchicine on microcrystal-induced COX-2 protein expression in human monocytes. Monocytes were incubated without or with MSU crystals (0.6 mg/mL) for 24 hours alone or in combination with various concentrations of colchicine (col) or with its inactive analogs, β- and γ-lumicolchicine (L-col), both at a concentration of 10 μmol/L. Cell samples were then processed for evaluation of immunoreactive COX-2 by immunoblot as described in Materials and Methods. (A) MSU crystal-stimulated cells. (B) Serum-treated zymosan (STZ; 100 μg/mL; 24 hours)-stimulated cells, in the presence of various concentrations (μmol/L) of colchicine. (C) Lipopolysaccharide (LPS; 2 μg/mL; 24 hours)-stimulated cells, in the presence of various concentrations (μmol/L) of colchicine. In each case, an immunoblot representative of at least three separate experiments is shown.