astragalin and Acute-Lung-Injury

Astragalin, a bioactive component of medicinal plants such as Rosa agrestis, has anti-inflammatory and antioxidant features. Induction of heme oxygenase (HO)-1 is an effective strategy to reduce excessive generated oxidants during the pathogenesis of acute lung injury (ALI). The aim of the present study is to investigate that whether the anti-inflammatory and antioxidant features of astragalin is HO-1 dependent in lipopolysaccharide (LPS)-induced ALI. Sprague-Dawley rats were used in animal study. Intratracheal LPS was performed to induce experimental ALI model. Astragalin was administrated 1 h after LPS challenge. Human lung epithelial cells were used in cell study. Samples from rats were harvested at 24 h post LPS challenge. Astragalin treatment inhibited LPS-induced inflammatory cells infiltration in the lung and pulmonary edema. Astragalin treatment markedly enhanced the activity of HO-1 compared with vehicle-treated group at 24 h post LPS challenge. Levels of lipid hydroperoxide, a marker for oxidative stress, were decreased in astragalin-treated animals compared with vehicle-treated group. However, the protective effect of astragalin on LPS-induced ALI was abolished in an inhibitor of HO-1-treated animals. Moreover, the astragalin-induced the upregulation of HO-1 in human lung epithelial cells was inhibited when nuclear factor erythroid-2-related factor 2 (Nrf2) was silenced by small interfering RNA. Astragalin reduces LPS-induced ALI via activation of Nrf2/HO-1 pathway.

Topics: Acute Lung Injury; Animals; Anti-Inflammatory Agents, Non-Steroidal; Antioxidants; Dose-Response Relationship, Drug; Female; Heme Oxygenase-1; Kaempferols; Lipopolysaccharides; Male; Molecular Conformation; Rats; Rats, Sprague-Dawley; Structure-Activity Relationship

Astragalin (AG), a flavonoid from many traditional herbs and medicinal plants, has been described to exhibit in vitro anti-inflammatory activity. The present study aimed to determine the protective effects and the underlying mechanisms of astragalin on lipopolysaccharide-induced endotoxemia and lung injury in mice. Mice were injected intraperitoneally (i.p.) with lipopolysaccharide (LPS) (dose range: 5-40 mg/kg). We observed mice on mortality for 7 days twice a day and recorded survival rates. In drug testing, we examined the therapeutic effects of astragalin (25, 50 or 75 mg/kg) on LPS- induced endotoxemia by dosing orally astragalin 1 hour before LPS challenge. Using an experimental model of LPS-induced acute lung injury (ALI), we examined the effect of astragalin in resolving lung injury. The investigations revealed that pretreatment with astragalin can improve survival during lethal endotoxemia and attenuate inflammatory responses in a murine model of lipopolysaccharide-induced acute lung injury. The mechanisms by which Astragalin exerts its anti-inflammatory effect are correlated with inhibition of tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1), and interleukin-6 (IL-6) production via inactivation of NF-κB.

Topics: Acute Lung Injury; Animals; Anti-Inflammatory Agents, Non-Steroidal; Disease Models, Animal; Down-Regulation; Endotoxemia; Kaempferols; Lipopolysaccharides; Male; Mice; Mice, Inbred BALB C; NF-kappa B; Pneumonia, Bacterial; Signal Transduction