miR-24-3p promotes spinal cord injury repair in rats by inhibiting ferroptosis <i>via</i> targeting GSK-3β.

OBJECTIVES: To investigate the molecular mechanism by which miR-24-3p promotes spinal cord injury (SCI) repair in rats. METHODS: Motor function recovery of the SCI rats was evaluated with BBB scores, histopathological changes and Fe²⁺ content in the SCI area were examined with HE staining and a commercial assay kit, and the changes in iron deposition in the SCI area was observed using Prussian blue staining with DAB. Western blotting and immunofluorescence staining were used to detect expressions of glycogen synthase kinase-3β (GSK-3β) and ferroptosis-related proteins xCT and GPX4 in the injured tissue. The targeted regulatory relationship between miR-24-3p and GSK-3β was verified using dual-luciferase reporter assay. In PC12 cells with erastin-induced ferroptosis, malondialdehyde (MDA) content was detected and the expression levels of GSK-3β, xCT and GPX4 proteins were determined by Western blotting and immunofluorescence staining. RESULTS: The expression of miR-24-3p and protein levels of xCT and GPX4 were significantly decreased in the SCI area of the rat models. Treatment with miR-24-3p agomir significantly improved hindlimb motor function of the SCI rats, alleviated spinal cord pathologies, reduced Fe²⁺ content, iron deposition and GSK-3β protein expression, and upregulated xCT and GPX4 protein expressions in the SCI area. Dual-luciferase reporter assay confirmed targeted inhibition of GSK-3β by miR-24-3p. In erastin-induced PC12 cells, transfection with miR-24-3p mimics significantly decreased intracellular MDA content and GSK-3β protein expression and increased xCT and GPX4 protein levels, and these effects were enhanced by co-transfection with GSK-3β inhibitor. CONCLUSIONS: miR-24-3p promotes repair of SCI in rats by inhibiting ferroptosis via targeted suppression of GSK-3β.