Figure 4. Effects of TGF-ß₁ and TGF-ß₃ on MMP-3 protein and activity levels in oral and skin fibroblast cultures. Each plot represents the mean ± SE of 3 paired fibroblast populations. Data are expressed as percentage change from control, where control values have been normalized to 100%. All culture conditions resulted in significantly increased protein and activity levels compared with controls (P < 0.05).