Figure 2. MMP-3 staining. (A) Intense immunoreactivity is seen in the adult periodontitis gingival tissue samples (n = 7). The fibroblast marked with an arrow is magnified 4x in the insert. (B) MMP-3 staining is weak in healthy tissue (n = 5), whereas (C) no staining is detected in the negative staining control. Scale bar = 100 µm.