Fig. 5. Exogenous MMP2 causes genital ridge apoptosis and loss of MMP2 impairs regression. (A) Hoechst staining (blue) reveals that exogenous MMP2 causes widespread death in the genital ridge compared to control cultures. Arrowheads indicate condensed apoptotic nuclei. Pax2 staining (red) shows the absence of the Müllerian duct after MMP2 treatment. GM6001 attenuates the effect of exogenous MMP2, indicated by the preservation of the Müllerian duct. (B) Antisense oligos against MMP2 (anti-MMP2) block Müllerian duct regression compared to control MMP2 oligos containing four mismatched bases (Mismatch). (Left panel) Full Müllerian duct regression is defined as the absence of any visible duct remnants. (Right panel) The percentage of Müllerian duct remnants present in genital ridge sections is shown for both anti-MMP2 and the control MMP2 oligonucleotide treatments (Mismatch). The number of each independent experiment or the number of sections examined is indicated in parentheses above the bars. *P=0.03; ** P=0.01. Müllerian duct remnants were judged by Pax2 staining as shown in C. (C) Representative examples of Hoechst (blue) and Pax2 (red) stained sections counted in B, show full regression of the Müllerian duct in control cultures treated with MIS, whereas both Müllerian and Wolffian ducts are often present in genital ridges treated with anti-MMP2 oligos. M, Müllerian duct; W, Wolffian duct.
