IL‑6/STAT3/miR‑34a protects against neonatal lung injury patients.

The present study aimed to investigate the protective role of the interleukin (IL)‑6/signal transducer and activator of transcription 3 (STAT3)/microRNA (miR)‑34a signaling pathway in patients with neonatal lung injury (NLI) and the underlying molecular mechanisms of these effects. It was demonstrated that miR‑34a serum expression was significantly upregulated in patients and mice with NLI. Meanwhile, IL‑6 and phosphorylated‑STAT3 protein expression, and tumor necrosis factor (TNF)‑α, IL‑1β and IL‑18 activity levels in NLI mice were significantly induced compared with the normal control group. The promotion of IL‑6 protein expression resulted in significantly increased TNF‑α, IL‑1β and IL‑18 activity levels, phosphorylated‑STAT3 and p65 protein expression, and miR‑34a expression in NLI mice compared with the corresponding normal control groups. In A549 cells treated with lipopolysaccharides, the promotion of miR‑34a protein expression significantly increased TNF‑α, IL‑1β and IL‑18 activity levels, and induced transcription factor p65 protein expression compared with the corresponding negative control groups. Collectively, the data of the present study indicate that IL‑6R/STAT3/miR‑34a possesses a protective role in patients with neonatal lung injury.