Abstract: Objective To explore the effect and mechanism of small RNA(sRNA)targeting at TNF-α in acute respiratory distress syndrome (ARDS). Methods Taking TNF-α as the target, screen sRNA from the sRNA database of Sini decoction by bioinformatics methods. The effect of sRNA targeting at TNF-α was verified by dual-luciferase reportergene system; the sRNA was transfected into the cells, then IL-1β, IL-6 and TNF-α of LPS or poly (I:C) induced A549 cells were detected by ELISA; the mRNA level of IL-1β, IL-6 and TNF-α in lipopolysaccharide(LPS) or poly(I:C) induced A549 cells was detected by RT-qPCR; Mild ARDS mouse models was developed by intratracheal instillation of LPS or poly(I:C) in mice. The mice were divided into native group, model group, NC group and sRNA-treated group. The concentration of IL-1β, IL-6 and TNF-α in BALF and serum was detected by ELISA. The survival of mild ARDS mouse models was observed. The survival rate of mice was counted. Results Bioinformatic analysis identified TNF-α mRNA binding 50 sRNAs and the dual-luciferase reporter gene system and THP1 inflammatory cell model identified the TNF-α-sRNA-9 that targeted at TNF-α, which was derived from Baked licorice in Sini decoction; Compared with NC group, TNF-α-sRNA-9 decreased the level of IL-1β, IL-6 and TNF-α in LPS or poly(I:C) induced A549 cells (P<0.05), and decreased the mRNA level (P<0.05). Compared with NC group, TNF-α-sRNA-9 treatment decreased the level of IL-1β, IL-6, and TNF-α in BALF and serum of mild ARDS mouse models induced by LPS or poly(I:C) (P<0.05) and increased the survival rate of mice. Conclusions TNFα-sRNA-9 alleviates lung injury in mild ARDS mouse models with potential mechanism of targeting at TNF-α.

Key words: acute respiratory distress syndrome, acute lung injury, small RNA, TNF-α, Sini decoction