Figure 3. MMP-3 mRNA expression. (a) MMP-3 RT-PCR products in oral and skin fibroblasts relative to β-actin products for control and TGF-β-treated conditions. Representative of duplicate experiments for 3 paired oral and skin populations. Appropriate PCR-negative blanks and RT controls were used during all electrophoresis runs (data not shown). (b) Effects of TGF-β₁ and TGF-β₃ on MMP-3 mRNA expression indices. Data are expressed compared with control cultures following normalization of control values for each cell population to 100%. Treatment with both factors, at all concentrations, induced a statistically significant increase in MMP-3 expression (p < 0.05).