MicroRNA‑146a/Toll‑like receptor 4 signaling protects against severe burn‑induced remote acute lung injury in rats via anti‑inflammation.

The present study investigated the preventive effects of microRNA (miR)‑146a against severe burn‑induced remote acute lung injury (ALI) in rats and the underlying mechanism. The surface area of the skin was immersed in 100˚C water for 5‑10 sec on the dorsal surface. The expression level of miR‑146a was significantly downregulated in rats with burn‑induced ALI. Downregulation of miR‑146a increased inflammation, and inducible nitric oxide synthase (iNOS) and cyclooxygenase‑2 (COX‑2) expression in a model of ALI in vitro via the promotion of the Toll‑like receptor (TLR)4/nuclear factor (NF)‑κB signaling pathway. In addition, the overexpression of miR‑146a reduced inflammation, and iNOS and COX‑2 protein expression in the model of ALI in vitro via the suppression of the TLR4/NF‑κB signaling pathway. A TLR4 inhibitor reduced the function of anti‑miR‑146a on inflammation in the model of ALI. Collectively, the results of the present study demonstrated the preventive effects of miR‑146a against severe burn‑induced remote ALI in rats through the anti‑inflammatory‑regulated TLR4/NF‑κB signaling pathway.