Fig. 2.

Effect of murine gelatinase B (mGelB) transfection in MMP-9 KO murine fibroblasts. A: effect on collagen gel contraction. Fibroblast-populated collagen gels were released into 60-mm tissue culture dishes. Gel size was measured daily with an image analyzer. Vertical axis, gel size expressed as % initial size; horizontal axis, time (days of culture); WT, murine fibroblasts from wild-type mice; KO, fibroblasts from MMP-9-deficient mice; KO + pRcCMV, MMP-9-deficient murine fibroblasts transfected with vector only; KO + pRcCMV/mGelB, MMP-9-deficient murine fibroblasts transfected with vector containing mGelB (MMP-9) sequence. B: gelatin zymography. After transfection of expression vector for murine MMP-9 to the murine MMP-9-deficient cells (KO), media were harvested at 24 h, and gelatin zymography was performed. The arrow indicates an apparent molecular size of 105 kDa, consistent with latent murine MMP-9. Media from HT1080 cells, which secrete copious amounts of human MMP-9, which has an apparent molecular size of 90 kDa, and MMP-2 are included as a positive control. *P < 0.05 compared with KO cells. Data are shown as means ± SE. Data presented are from one representative experiment performed in triplicate on three separate occasions.