Endometritis is correlated to repeated implantation failures. MicroRNA (miRNA) participates in several inflammatory diseases and miR-124 is involved in many diseases. Bone marrow stromal cells (BMSCs) are closely connected to the regulation of inflammation. Human endometrial epithelial
cells (HEECs) were cultured in vitro, assigned into control group, LPS group and BMSC group, and miR-124 overexpressing BMSCs were constructed and co-cultured with HEECs followed by analysis of HMGB1 and NF-κB expression by Western Blot, and the proliferation and apoptosis
of HEECs. In LPS group, HEECs proliferation and miR-124 decreased, apoptosis and HMGB1 increased (P < 0.05). After co-culture with BMSCs, it can promote HEECs proliferation, inhibit apoptosis, increase miR-124, and decrease HMGB1, NF-κb and the secretion of inflammatory
factors (P < 0.05) with more significant changes in the high miR-124 expression group. miR-124 in endometritis endometrial epithelial cells is downregulated. In conclusion, BMSCs with high expression of miR-124 can inhibit inflammation and regulate endometrial epithelial cell apoptosis
by regulating HMGB1 and NF-κB, thereby promoting endometrial epithelial cells proliferation and delaying endometritis progression.