Abstract: Objective To investigate the role of microRNA-873-5p (miR-873-5p) in regulating the senescence of mesenchymal stem cells (MSCs) and to explore whether inhibition of miR-873-5p can rejuvenate senescent MSCs, thereby enhancing their therapeutic efficacy on myocardial infarction (MI).Methods MSCs were isolated from young donors (young MSCs, YMSCs) and aged donors (aged MSCs, AMSCs), and cellular senescence was assessed by senescence-associated β-galactosidase (SA-β-gal) staining. Subsequently, these MSCs, including AMSCs treated with anti-miR-873-5p, were transplanted into the heart of SD rats with MI.Results Upregulation of miR-873-5p in YMSCs exacerbated cellular senescence, while downregulation of miR-873-5p in AMSCs alleviated senescence. Mechanistically, miR-873-5p inhibited autophagy in MSCs via the AMPK signaling pathway and promoted cellular senescence by inhibiting Cab39 expression. The use of the autophagy inhibitor 3-methyladenine partially counteracted this effect. Compared with the transplantation of untreated AMSCs, transplantation of anti-miR-873-5p-treated AMSCs improved cell survival and enhanced cardiac function in rats.Conclusions MiR-873-5p plays a key role in mediating MSC senescence by regulating the Cab39/AMPK signaling pathway, suggesting its role as an innovative target for rejuvenating senescent MSCs and enhancing their cardioprotective abilities.