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Figure 2. Triggering of the plasmin/MMP-3/MMP-1 proteolytic cascade and collagenolysis in elastin peptides (100 µg/mL)-treated floating gingival-fibroblast-populated collagen lattices (FCL) following 4 days of culture. FCL was prepared with 2.5% serum. Plasmin activity (A) was determined with S2251 as substrate, and MMP-3 (B), MMP-1 (C), TIMP-1 (E), and TIMP-2 (F) were analyzed by Western blotting; TIMPs were also identified by gelatin reverse zymography (D). Collagen degradation was quantified by hydroxyproline assay (G). The numbers 1, 2, 3, and 4 refer to control, FCL cultured in the presence of 100 µg/mL kE, FCL cultured in the presence of plasminogen (30 µg/mL), and FCL cultured in the presence of both kE and plasminogen, respectively. Variations are representative of separate experiments performed in triplicate with 4 different cell strains. Bars indicate standard deviations. Significantly different from control: O, p < 0.05; OO, p < 0.01; OOO, p < 0.001.
