title: [Effects of quercetin on serum levels of resistin and IL-18 and on insulin resistance in nonalcoholic fatty liver disease rats].
abstract: OBJECTIVE
  To investigate the effects of quercetin on serum levels of resistin and interleukin (IL)-18 and incidence of insulin resistance (IR) in nonalcoholic fatty liver disease (NAFLD) using a rat model.
  
  
  METHODS
  NAFLD was induced in Sprague-Dawley rats by administering a high-fat diet for four weeks. The model rats were then treated with quercetin (oral gavage administration; low dose group: 75 mg/kg/day, high dose group: 300 mg/kg/day) for eight weeks. Untreated model rats served as controls. Serum levels of resistin, triglyceride (TG), IL-18, fasting plasma glucose (FPG), fasting insulin (FINS), and malondialdehyde (MDA) were measured by standard biochemical assays before and after the quercetin administration. In addition, the insulin resistance index (HOMA-IR) was calculated and pathological changes in liver were observed by histological analysis.
  
  
  RESULTS
  Compared to the untreated model rats, the quercetin treated model rats showed significantly lower serum resistin (5.98 vs. 2.70), serum IL-18 (10.93 vs. 8.21), FPG (7.45 vs. 4.99), FINS (12.69 vs. 8.59), and HOMA-IR (4.22 vs. 1.87) (all P less than 0.01). Compared to the untreated model group, the high dose group showed significantly lower TG (t = 4.70) and MDA (t = 5.14) (both P less than 0.01). Serum levels of resistin and IL-18, and levels of TG, FPG and FINS were found to be positively correlated with HOMA-IR and the degree of liver disease (r more than 0, all P less than 0.05). The degree of degeneration was decreased in accordance with the dosages of quercetin, as compared to the untreated model group (U = 4.41 and 2.19, both P less than 0.05), and the pathological degree was less extensive in the high dose group than in the low dose group (U = 2.44, P less than 0.01).
  
  
  CONCLUSIONS
  Quercetin treatment reduces levels of inflammatory cytokines and improves lipid peroxidation and IR in NAFLD rats, and its beneficial effects appear to increase with higher dosage.
authors.affiliation: Department of Infectious Diseases, the Affiliated Hospital of Guangxi Guilin Medical College, Guilin 541001, China.
authors.forename: Mao-Hua
authors.initials: MH
authors.lastname: Zhang
authors.forename: Zhi-Qing
authors.initials: ZQ
authors.lastname: Liang
authors.forename: Qing
authors.initials: Q
authors.lastname: Qin
authors.forename: Sheng-Lian
authors.initials: SL
authors.lastname: Li
authors.forename: Dong-Sheng
authors.initials: DS
authors.lastname: Zhou
authors.forename: Ling
authors.initials: L
authors.lastname: Tang
mesh_terms: D000818:Animals; D007333:Insulin Resistance; D020382:Interleukin-18 / Q000097:blood; D065626:Non-alcoholic Fatty Liver Disease; D011794:Quercetin; D051381:Rats; D017207:Rats, Sprague-Dawley; D052243:Resistin
chemical_list: D020382:Interleukin-18; D052243:Resistin; D011794:Quercetin