Figure 6.

 Secreted products of monocytes induced by PM_ap. (a and b) Increase in MMP9 collagenolytic activity in supernatant of THP-1 cells, following incubation with vehicle control (ctrl), PMA (10 ng/ml), PM_ap or resting platelets (plts) for 44 h or 7 days. (a) Representative inverse zymograms of supernatants subjected to gel electrophoresis; note dark digestion bands at 260 kDa and 98 kDa. (b) Densitometric quantification of gelatinolytic activity of the 98-kDa band (mean gray value). Please note that gray value is inversely correlated with protease activity. (c and d) Quantification of H₂O₂ production after 20–44 h of incubation in supernatants from THP-1 cells (c) or monocytes after 44 h (d). Parallel tests gave fractions of non-viable cells of <0.3% (44 h) for THP-1 and monocytes, after 7 days 6–7% or 2–3%, respectively, under all conditions. Mean±S.E.M. (n=3). ^*P<0.05 versus control