title: Quercetin protects against lipopolysaccharide-induced acute lung injury in rats through suppression of inflammation and oxidative stress.
abstract: BACKGROUND
  Acute lung injury (ALI) is an acute inflammatory disease characterized by excess production of inflammatory factors in lung tissue. Quercetin, a herbal flavonoid, exhibits anti-inflammatory and anti-oxidative properties. This study was performed to assess the effects of quercetin on lipopolysaccharide (LPS)-induced ALI.
  
  
  METHODS
  Sprague-Dawley rats were randomly divided into 3 groups: the control group (saline alone), the LPS group challenged with LPS (Escherichia coli 026:B6; 100 µg/kg), and the quercetin group pretreated with quercetin (50 mg/kg, by gavage) 1 h before LPS challenge. Bronchoalveolar lavage fluid (BALF) samples and lung tissues were collected 6 h after LPS administration. Histopathological and biochemical parameters were measured.
  
  
  RESULTS
  The LPS treatment led to increased alveolar wall thickening and cellular infiltration in the lung, which was markedly prevented by quercetin pretreatment. Moreover, quercetin significantly (p < 0.05) attenuated the increase in the BALF protein level and neutrophil count and lung wet/dry weight ratio and myeloperoxidase activity in LPS-challenged rats. The LPS exposure evoked a 4- to 5-fold rise in BALF levels of tumor necrosis factor-α and interleukin-6, which was significantly (p < 0.05) counteracted by quercetin pretreatment. Additionally, quercetin significantly (p < 0.05) suppressed the malondialdehyde level and increased the activities of superoxide dismutase, catalase, and glutathione peroxidase in the lung of LPS-treated rats.
  
  
  CONCLUSIONS
  Quercetin pretreatment effectively ameliorates LPS-induced ALI, largely through suppression of inflammation and oxidative stress, and may thus have therapeutic potential in the prevention of this disease.
authors.affiliation: Department of Thoracic Surgery, Wenzhou Central Hospital, Wenzhou, China.
authors.forename: Risheng
authors.initials: R
authors.lastname: Huang
authors.affiliation: Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China.
authors.forename: Tian
authors.initials: T
authors.lastname: Zhong
authors.affiliation: Department of Clinical Laboratory, Wenzhou Central Hospital, Wenzhou, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Wu
keywords: acute lung injury; inflammation; oxidative stress; quercetin