Modulation of 72-Kilodalton Type IV Collagenase: DISCUSSION(1)
Type I, type III, and type IV collagens are the main structural constituents of chorioamniotic membranes, and they are responsible for the strength and flexibility of the membranes. In this study, it was demonstrated that vitamin C, in addition to its well-known role in collagen biosynthesis, modulates the degradation of this protein. The regulatory effect of vitamin C is exerted on the 72-kDa type IV collagenase or MMP-2 gene expression. MMP-2 is the only MMP secreted by WISH cells under experimental conditions. This peculiarity makes WISH cells a good model for study of MMP synthesis and secretion in chorioamnion during gestation. The unique presence of MMP-2 in am-niotic fluid and fetal membranes during midgestation suggests its role in extracellular matrix remodeling in cho-rioamnion. MMP-2 degrades type IV collagen, which is found in association with basal membranes but in chorioamnion is very widespread in a network. buy prednisone
Vitamin C was carried by cultured cells under experimental conditions, and even with the low intracellular concentration, the effect on MMP-2 expression was demonstrated. The slow cellular intake may be explained by the fetal calf serum-free conditions that are necessary for the MMP-2 enzymatic activity assays. Fetal calf serum is contaminated with variable amounts of vitamin C and several MMPs that mask the effect on MMP-2 expression, as reported previously.