MiR-543-5p inhibits inflammation and promotes nerve regeneration through inactivation of the NF-κB in rats after spinal cord injury

OBJECTIVE: The aim is to determine the efficacy and specific mechanism of microRNA-543-5p (miR-543-5p) on spinal cord injury (SCI). MATERIALS AND METHODS: The model of spinal cord injury was established in 6-week-old rats. Firstly, quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was used to detect the changes of miR-543-5p in the spinal cord of rats in each group after spinal cord injury. Next, we observed the alterations in nuclear factor-kappa B (NF-kappa B) RNA level after injection of miR-543-5p. In addition, the enzyme-linked immunosorbent assay (ELISA) was used to detect the expression of the inflammatory cytokines, and we used Western blotting to detect the protein associated with nerve regeneration at the protein levels. Finally, the Basso-Beattie-Bresnahan (BBB) rating scale was utilized to measure the recovery of hindlimbs function in rats. RESULTS: After spinal cord injury, the RNA expression of miR-543-5p in the rat spinal cord was decreased, and the RNA level of NF-kappa B was found to be decreased after the artificial injection of miR-543-5p. In the inflammatory expression, we found that the expression of various inflammatory mediators was also downregulated. However, the expression of nerve regeneration related factors was significantly upregulated, and it was observed that the evaluated score of the miR-543-5p group was higher than that of the SCI group within 1 month. CONCLUSIONS: MiR-543-5p inhibited NF-kappa B pathway and reduced the inflammatory factors, and ameliorated nerve regeneration, which ultimately promoted hindlimbs locomotor function.