Dulcitol ameliorates LPS-induced acute lung injury (ALI) in mice by inhibiting TLR4/NF-κB activation

The identification of natural compounds with therapeutic efficacy for acute lung injury has consistently represented a critical area of research. Dulcitol, a natural product isolated from plants, is extensively used in the food and medical industries as a sweetener. Herein, we investigated whether dulcitol exerts an anti-inflammatory effect on LPS-induced acute lung injury (ALI) in mice. In our study, ICR mice were pretreated with dulcitol at dose of 6, 12 and 24 mg/kg for seven consecutive days, followed by intratracheally instilled with LPS (10 mg/kg) to induce acute lung injury. In vitro, RAW264.7 and A549 cells were incubated with LPS in the presence of dulcitol to investigate the anti-inflammatory activity and mechanism. The results demonstrated that dulcitol effectively inhibited the infiltration of inflammatory cells and reduced the excessive production of pro-inflammatory cytokines triggered by LPS to ameliorates acute lung injury in mice. Additionally, in vitro experiments indicated that dulcitol suppressed the release of NO, IL-6 and TNF-α while reducing mRNA expression levels of IL-1β, IL-6, COX-2, iNOS and TNF-α in RAW264.7 and A549 cells in a dose-dependent manner. Furthermore, dulcitol significantly decreased TLR4, MyD88, and TRIF levels and inhibited the translocation of NF-κB from the cytoplasm to the nucleus. Our finding suggested that dulcitol could serve as a protective agent against LPS-induced acute lung injury by inhibiting the TLR-4/NF-κB signaling pathway.