Menstrual-Blood Serum Displays an Antifibrotic Effect on Human Endometrial Mesenchymal Stromal Cells

The endometrium of reproductive-age women is capable of epimorphic regeneration, which is unique to human beings. Its key feature is a wound-healing stage, which ends not in scar formation, but in complete restoration of the normal structure of uterine mucosa. The participation of endometrial mesenchymal stromal cells (eMSC) in wound healing may be due to specific environment formed during menstruation. Menstrual blood is secreted from the wound throughout the entire healing process. We decided to use serum to model the effects of the environment-soluble part on eMSC. Peripheral-blood serum (PBs) served as a control. We found that menstrual-blood serum (MBs) affected eMSC proliferation and morphology and reduced expression of α-smooth-muscle actin. Unlike fetal bovine serum (FBs), both MBs and PBs induced expression of VE-cadherin in eMSC. Expression of E-cadherin was independent of the sera used. These findings suggest antifibrotic effect of menstrual blood on eMSC.