LAUSR

Exosomes (Exo) originated from bone marrow mesenchymal stem cells (BMSCs) have therapeutic impacts on osteonecrosis of the femoral head (ONFH), and microRNA (miR)‐532‐5p has been confirmed to participate in ONFH progression. In the research, it was figured out whether BMSCs‐Exo could relieve ONFH by delivering miR‐532‐5p. MG‐63 cells were treated with DEX to construct an ONFH cell model in vitro. The effects of Exo and miR‐532‐5p on the cell viability, lactate dehydrogenase (LDH) content, and apoptosis of BMSCs were detected. The ONFH rat model was established, and the effect of BMSCs‐Exo delivering miR‐532‐5p on the pathological damage of ONFH rats was evaluated. Changes in nuclear receptor coactivator‐3 (NCOA3) and apoptotic proteins were assessed by western blot. The relationship between miR‐532‐5p and NCOA3 was verified by dual luciferase reporter experiments. miR‐532‐5p was elevated in vivo and in vitro ONFH‐models, while NCOA3 expression was reduced. Overexpression of miR‐532‐5p aggravated DEX toxicity in osteoblasts, decreased cell viability, and promoted apoptosis. Knockdown of miR‐532‐5p made Exo further attenuate the toxic effect of DEX on osteoblasts and inhibited apoptosis. The protective effect of miR‐532‐5p‐delivering Exo on osteoblasts was reversed by NCOA3 silencing. In addition, in vivo experiments also confirmed that knockdown of miR‐532‐5p enhanced the therapeutic effect of Exo on ONFH rats. This study demonstrates that miR‐532‐5p‐delivering BMSCs‐Exo inhibits osteoblast viability and promote apoptosis by targeting NCOA3, thereby aggravating ONFH development.