Aim
Endometrial tissue inhibitors of metalloproteinases (TIMPs) appear to play an essential role during early implantation by modulating the invasiveness of the trophoblast. The expression of TIMP-1, TIMP-2 and TIMP-3 in human endometrial stromal cells (ESC) was investigated during decidualization in vitro.
Methods
Endometrial stromal cells were isolated from hysterectomy specimens from premenopausal women undergoing surgery for benign reasons. Decidualization in vitro was induced by the application of 1 μmol/L progesterone and 30 nmol/L 17β-estradiol over 9 days. The expression of TIMP-1, TIMP-2 and TIMP-3 in ESC was measured by semiquantitative real-time reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay over intervals of 3 days.
Results
Decidualization in vitro was confirmed by a significant increase in prolactin expression. TIMP-1 and TIMP-2 mRNA and secreted protein showed no significant changes over the time-course of decidualization. In contrast, TIMP-3 was upregulated during the first 3 days of decidualization. An eightfold upregulation was observed until day 6, and the effect was less pronounced by day 9.
Conclusion
These results suggest a regulatory role of the TIMP system for endometrial differentiation in the second half of the menstrual cycle and in early implantation. The expression pattern of endometrial TIMP-3 might be important for the regulation of trophoblast invasion.