Immunostainig of MMP-9 and MMP-3 in sections of human FT ampulla, throughout the menstrual cycle. Positive staining of MMP-9 in follicular phase at lower magnification (A); note the complete absence of label in negative control in the small square at the right (B). Staining of MMP-9 at higher magnification in follicular (C), periovulatory phase (D) and luteal phase (E). Positive staining of MMP-9 in follicular phase (F), periovulatory phase (G) and luteal phase (H). Note the similar stromal distribution of MMP-9 and MMP-3 in the sections. The arrows indicates positive brown immunostaining, counterstaining was performed with hematoxylin. Scale bar = 100 μm.