Effects of MiR-146a on Repair and Inflammation in Rats with Spinal Cord Injury Through the TLR/NF-κB Signaling Pathway

Objective: This study aims to investigate the effects of micro ribonucleic acid-34a (miR-34a) on repair and inflammation of rats with spinal cord injury (SCI) through the toll-like receptor (TLR)/nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway.

Materials And Methods: In this study, 12 healthy rats (control group (CG)) and 24 SCI rats (experimental group (EG-1)) were selected as subjects. A total of 12 experimental rats randomly selected from EG-1 were injected with 5 µL agomiR-146 as EG-2 group. Serum levels of miR-146a, TLR, NF-κB, interleukin-8 (IL-8) and IL-6 of rats in CG and EG-1 were detected by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Furthermore, the protein levels of miR-146a, TLR, NF-κB, IL-8 and IL-6 in rats of CG and EG were detected via Western blotting. Spinal cord tissue sections of SCI rats after treatment with agomiR-146 were observed by hematoxylin and eosin staining (H&E) staining.

Results: The mRNA level of miR-146a in SCI rats was significantly lower than that in healthy rats, and the difference was statistically significant (p < 0.05). The mRNA levels of TLR, NF-κB, IL-8 and IL-6 in SCI rats were markedly higher than those in healthy rats, showing significant differences (p < 0.05). However, the relative mRNA level of miR-146a in EG-2 group was significantly higher than that in EG-1 group, with a significant difference (p < 0.05). Relative level of miR-146a was not significantly different between EG-2 group and CG group (p > 0.05). Meanwhile, the mRNA levels of TLR, NF-κB, IL-8 and IL-6 in EG-2 group were evidently lower than those in EG-1 group, displaying significant differences (p < 0.05).

Conclusions: MiR-146a can promote the repair of SCI and reduce inflammatory responses in rats through the TLR/NF-κB signaling pathway.