Simvastatin, which is primarily prescribed to lower cholesterol, may also mitigate lung injury caused by sepsis, although the mechanisms remain elusive. This study aimed to evaluate the protective effect of simvastatin on acute lung injury in rats with sepsis and to investigate possible mechanisms. Male Wistar rats were pretreated with simvastatin (0.2 μg/g) for 1 week before cecal ligation and puncture. Treatment with simvastatin demonstrated significant decreases in the concentration of protein, TNF-α, IL-1β, IL-6, and lipocalin 2, and the number of polymorphonuclear neutrophils in bronchoalveolar lavage fluid in septic rats. In addition, simvastatin also reduced levels of Evans blue, malondialdehyde, 8-hydroxy-2'-deoxyguanosine, and wet/dry lung weight ratios, and increased the activity of superoxide dismutase in lung tissue. Furthermore, expression levels of TLR4, NF-κB p65, and active caspase-3 proteins and Bax mRNA were also decreased by simvastatin. H&E staining showed that severe lung injury occurred in the sepsis group and that lung injury was reduced by treatment with simvastatin. In conclusion, simvastatin improved endothelial permeability and mitigated the inflammatory response of lung tissue, the oxidative stress response, and cell apoptosis by inhibiting the TLR4/NF-κB signaling pathway, thereby alleviating sepsis-induced acute lung injury in rats.
Keywords: TLR4/NF-κB; acute lung injury; sepsis; simvastatin.