Expression of matrix metalloproteinases and their tissue inhibitors in ovaries of senescence accelerated mice

Abstract

We have shown that some corpora lutea (CLs) were abnormally accumulated in the ovaries of female SAMP1 mice. No significant differences in peripheral blood levels of progesterone or 17β-estradiol during estrus cycle were noted between SAMP1 and control-SAMR1 mice, and high activity of 20α-hydroxysteroid dehydrogenase was detected only in abnormally accumulated CLs (aaCLs) of SAMP1 mice. In the ovaries of SAMP1 mice, structural regression is inhibited in aaCLs, but functional regression does occur. In this study, we focused on the matrix metalloproteinases (MMPs) and tissue inhibitors of MMP (TIMPs), regulators of angiogenesis and angiodegeneration. In situ zymography (FIZ), terminal deoxynucleotidyl transferase-mediated biotinylated deoxyuridine triphosphate nick end-labeling (TUNEL) staining and histochemistry for hydroxysteroid dehydrogenases revealed that many TUNEL-positive apoptotic cells in regressing CLs of both SAMR1 and SAMP1 mice, but no apoptotic cells, were demonstrated in aaCLs of SAMP1 mice. MMPs and their mRNAs were detected in all ovaries of both SAMR1 and SAMP1 mice. In the murine ovaries, negative/trace activity of non-MMP proteinases was detected by FIZ techniques. Moderate/strong activities of MMPs were demonstrated in CLs of SAMR1 mice and in regressing CLs of SAMP1 mice, but trace MMP activity was noted in aaCLs of SAMP1 mice.