Correlation of RECK with matrix metalloproteinase-2 in regulation of trophoblast invasion of early pregnancy.

To study the role of the reversion-inducing-cysteine-rich protein with Kazal motifs (RECK) gene and matrix metalloproteinase-2 (MMP-2) in the regulation of trophoblast invasion of early pregnancy. Immunohistochemistry, Western blot and gelatin zymography were used to detect the RECK protein expression localization, expression level and MMP-2 activation level in the placental tissues harvested from 52 normal pregnant women (27 in the early pregnancy, 25 in the term pregnancy). Immunohistochemistry showed that RECK expression was found both in villous tissues of early pregnancy group and term pregnancy group and was mainly observed in cell membrane and cytoplasm of cytotrophoblasts and syncytiotrophoblasts. RECK expression increased with gestational time. RECK expression of early pregnancy group was significantly lower than that of term pregnancy group (P<0.05). RECK expression was significantly lower in cellular column (CC) with invasion ability. Western blot showed that the RECK protein expression in early pregnancy group was significantly lower than that in term pregnancy (P<0.05). The optical density values of RECK protein expression in early pregnancy group and term pregnancy group were 1.35-0.14 and 2.68+/-0.26, respectively, while MMP-2 activation ratio was contrary to RECK protein expression and decreased with the gestation time (P<0.01). The MMP-2 activation ratios of early pregnancy group and term pregnancy group were 0.46 +/- 0.05 and 0.10+/-0.02, respectively. The expression of the tumor inhibitory gene RECK was positively related with the invasion ability of trophoblasts, while the invasion gene MMP-2 was negatively related with the ability. The interaction between RECK and MMP-2 may play an important role in the regulation of the trophoblast invasion in early pregnancy.