Prostaglandin E2 (PGE2) and matrix metalloproteases (MMPs) 2 and 9. Culture media were harvested after four days in the presence of neutrophil elastase (NE), indomethacin or exogenous PGE2. (a) Fibroblasts alone. MMP-2 latent (72 kDa) and active (66 kDa) forms are shown. Lane 1: control; lane 2: NE; lane 3: indomethacin; lane 4: PGE2. (b) Monocytes co-cultured with fibroblasts. MMP-9 latent (92 kDa) and active (83 kDa) forms are shown in addition to MMP-2 forms. Lane 1: control; lane 2: NE; lane 3: indomethacin; lane 4: NE + indomethacin; lane 5: PGE2; lane 6: NE + PGE2; lane 7: NE + indomethacin + PGE2.