MMP-2 contributes to the development of the mouse ventral prostate by impacting epithelial growth and morphogenesis

Epithelial growth, branching, and canalization are important morphogenetic events of the rodent ventral prostate (VP) that take place during the first postnatal week. In this study, we evaluated the effect of knocking out MMP-2 (MMP-2(-/-)), by examining developmental and structural aspects of the VP in MMP-2(-/-) mice. Neonate (day 6) MMP-2(-/-) mice showed fewer epithelial tips, a lower epithelial cell proliferation rate, and also reticulin fiber accumulation. The VP of adult MMP-2(-/-) mice showed lower relative weight, smaller epithelial and smooth-muscle cell volume, and a larger amount of thicker reticulin fibers. No differences in cell proliferation or apoptotic index were noted between adult MMP-2(-/-) and wild-type mice. MMP-9 was found in the adult MMP-2(-/-), but not in the wild-type. In conclusion, MMP-2 function is essential for the epithelial morphogenesis of the mouse VP, and expression of MMP-9 is not sufficient for acquisition of the normal adult histology.