Zymography and in situ hybridization were used to investigate matrixmetalloproteinase -2, -9 (MMP -2, MMP-9) activities and expressions of MMP -2, -9 and TIMP1, -2, -3 (tissue inhibitors of matrix metallo-proteinases) mRNA in the rat uterus during estrouscycle. The relative activity was semiquanted by using densitometric analysis. The MMP-2(67 kDa) activity in every stage during estrpus cycle was detected by zymography. MMP-2activity was highest at proestrus; higher at estrus and metaestrus; lowest at diestrus. Throughin situ hybridization, MMP -2, -9, TIMP -1~ -3 mRNA mainly in hasal stroma cells of uterineendometrium were detected. The positive signals of MMP -2 and -9 mRNAs in hasal stromacells were shown stronger at proestrus, estrus and metaestrus while they showed the weakest atdiestrus. The expression of MMP -2 mRNA coincided with MMP -2 activity change. MMP-2and -9 mRNAs were also highly expressed in uterine circular muscle at estrus. Weak signals ofMMP -9 mRNA were detected in uterine luminal and glandular epithelial cells at estrus.TIMP -1 mRNA in hasal stroma cells was shown as the strongest expression at estrus andmetaestrus; stronger at proestrus and the weakest at diestrus. TIMP-2 mRNA in basal stromacells was stronger at estrus and diestrus; weaker at proestrus and metaestrus. TIMP -1 and -2mRNAs were also highly expressed in uterine luminal and glandular epithelial cells at estrus.TIMP -3 mRNA in hasal stroma cells revealed the strongest expression at estrus; stronger atdiestrus and metaestrus and showed the weakest at proestrus. The mRNA was also highlyexpressed in uterine circular muscle at estrus. In short, our present results provide evidencethat MMP -2, -9 and TIMP -1~ -3 were involved in rat uterine endometrium reconstructionduring estrous cycle.
