Rat Amnion Type IV Collagen Composition and Metabolism: DISCUSSION(1)

9 May

The present report documents that type IV collagen is lost from the rat amnion before the onset of labor. The relative decline in type IV collagen could be the result of diminished synthesis, accumulation of other proteins in the amnion which alters the relative abundance of type IV collagen, increased degradation, or a combination of these processes. There is increased expression of two enzymes that degrade type IV collagen, MMP-2 and MMP-9, by Day 21 of pregnancy. Buy Advair Diskus Online

The increase in MMP-9 is particularly striking as no MMP-9 activity could be detected by zymography before the evening of Day 20 of pregnancy, whereas MMP-2 activity was detectable on all days of gestation, with an increase by Day 21. Since amnion type IV collagen levels are reduced to some extent before the rise in MMP-2 and MMP-9 protein and activity, it is likely that these enzymes are not responsible for this phase of the decline. Our previous ultrastructural studies disclosed loss of amnion basement membrane and epithelial cell delamination starting on the evening of Day 20, with pronounced alterations by Day 21.