hUMSCs Transplantation Regulates AMPK/NR4A1 Signaling Axis to Inhibit Ovarian Fibrosis in POI Rats

The mechanism of human Umbilical Cord Mesenchymal Stem Cells (hUMSCs) transplantation to improve ovarian function in the rats with Premature Ovarian Insufficiency (POI) is still unclear. The aim of this study is to investigate the signal axis mechanism that is involved in the ovarian function recovery of POI rats following hUMSCs transplantation.The rat model with POI was established by intraperitoneal injection of cisplatin. The hUMSCs were transplanted by caudal vein injection into POI rats. Hematoxylin-eosin (H&E) staining was performed to examine the morphology of rat ovarian tissue. Masson staining, Sirus red staining and immunofluorescence were used to observe the fibrosis extent of ovarian tissue. The levels of serum sex hormones and the expression of fibrosis related markers in ovarian tissues were measured by enzyme-linked immunosorbent assay (ELISA). The expression of NR4A1, Phospho-NR4A1 and AMP-activated protein kinase (AMPK) signaling in rat ovarian tissues was measured by immunohistochemistry and immunofluorescence. The role of AMPK/NR4A1 signaling axis in the regulation of ovarian function recovery in POI rats following hUMSCs transplantation was further investigated by adenovirus and siRNA intervention in isolated stromal cells.The results showed that the hUMSCs transplantation significantly inhibited ovarian tissue fibrosis and restored the ovarian function in POI rats. The level of NR4A1 and AMPK expression in ovarian tissue of POI rats after hUMSCs transplantation was significantly increased compared with the control group. In the cultured ovarian stromal cells, the similar results were obtained on the expression of NR4A1 and its regulation on fibrosis related molecular markers in Cisplatin (CDDP) damaged stromal cells following hUMSCs supernatant treatment. Both hUMSCs supernatant treatment and the addition of AMPK inhibitors increased NR4A1 expression in stromal cells. And after NR4A1 molecular intervention, fibrosis-related indicators in stromal cells changed. The data suggests that the AMPK/NR4A1 signaling axis is involved in the ovarian function changes in POI rats following hUMSCs transplantation.The data from this study indicate that the inhibition of tissue fibrosis and recovery of ovarian function is regulated by AMPK/NR4A1 signaling axis in POI rats following hUMSCs transplantation.