Mesenchymal stem cells and their conditioned medium can enhance the repair of uterine defects in a rat model.

BACKGROUND: Our aim was to examine the roles of mesenchymal stem cell (MSC) transplantation in the repair of large uterine defects.

METHODS: Uterine defects were created in both uterine horns of female rats by a punch instrument, and bone marrow-derived MSCs, MSC-conditioned medium (MSC-CM) or vehicle were injected into the myometrium around the defect. The rate of uterine defect repair was monitored on day 2 and 4 after operation. Cytokine array of MSC-CM was performed, followed by neutralizing antibody experiments to clarify the exact cytokine participating in the MSC-CM-enhanced wound repair.

RESULTS: Transplantation of MSCs, but not myometrial cells, significantly enhanced uterine defect repair. The transplanted MSCs were detected in the uterine horn with no signs of rejection on day 4 after transplantation, when the MSC-transplanted uterine wound was nearly healed. Moreover, uterine defect repair was also accelerated by injection of MSC-CM, indicating the paracrine effects of MSCs on uterine wound healing. Cytokine array analysis further revealed that MSC-CM contained abundant cytokines and chemokines, among which high levels of interleukin-6 (IL-6) were found. Additionally, antibodies against IL-6 were shown to block MSC-CM-enhanced uterine defect repair.

CONCLUSION: This study demonstrated that transplantation of MSCs could enhance uterine defect repair by paracrine effects involving IL-6, which are findings that may be applied to facilitate uterine wound healing in the removal of huge intramural masses.