Propofol Inhibits Lipopolysaccharide-induced Lung Epithelial Cell Injury by Reducing Hypoxia-inducible Factor-1alpha Expression

Background: Lipopolysaccharide (LPS) may activate hypoxia-inducible factor (HIF)-1α, which up-regulates cytokine expression and the lethality of LPS-induced shock. We investigated the effect of propofol on HIF-1α expression and acute lung injury in LPS-treated mice.

Methods: A series of both positive and negative control experiments were performed. We injected BALB/C mice with propofol or vehicle i.p. immediately and 12 h after an LPS challenge. After 24 h, we examined the lung wet/dry weight ratio, neutrophil infiltration, and HIF-1α mRNA expression and inflammatory cytokines in the lung tissue. Survival was determined for 48 h after LPS injection. In vitro, we determined the responses of A549 cells, with and without HIF-1α silenced, to treatment with LPS alone and LPS plus propofol.

Results: Propofol prolonged survival and attenuated acute lung injury and decreased the expression of HIF-1α, interleukin (IL)-6, keratinocyte-derived chemokine, and tumour necrosis factor-alpha (TNF-α) in the lungs of endotoxaemic mice. In HIF-1α knockdown-A549 cells, LPS-induced TNF-α, IL-6, and the pro-apoptotic gene, BNIP3 expression and apoptosis were reduced. Propofol, but not an inhibitor of nuclear factor κB, reduced HIF-1α expression in LPS-stimulated A549 cells. Propofol also down-regulated, in A549 cells, the expression of IL-6, IL-8, and TNF-α, Bcl-2/adenovirus E1B 19 kDa interacting protein 3 (BNIP3), and apoptosis.

Conclusions: Propofol reduces apoptosis in LPS-stimulated lung epithelial cells by decreasing HIF-1α, BNIP3, and cytokine production. Using propofol to inhibit HIF-1α expression may protect against the acute lung injury caused by LPS-induced sepsis.