Effects of quercetin on serum levels of resistin and IL-18 and on insulin resistance in nonalcoholic fatty liver disease rats / 中华肝脏病杂志

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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).</p><p><b>CONCLUSION</b>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.</p>

Therapeutic efficacy and mechanisms of quercetin in a rat model of nonalcoholic fatty liver disease / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To determine the efficacy of the plant-derived bioflavonoid, quercetin, for treating nonalcoholic fatty liver disease (NAFLD) by using a rat model, and to investigate the molecular mechanism underlying its therapeutic effects.</p><p><b>METHODS</b>One-hundred Sprague-Dawley rats were randomly assigned into the normal control group (normal group), untreated NAFLD model control group (model group), 75 mg/kg/day quercetin treatment group (low-dose group), and 300 mg/kg/day quercetin treatment group (high-dose group). The NAFLD rat model was established by providing four weeks of a high-fat diet; the normal group received normal rat chow diet. The quercetin treatments were administered for eight weeks after model establishment and control groups received simultaneous gavages of isotonic saline, with continuation of the respective diets. At the end of the eight weeks (experimental week 12), the rats were sacrificed for liver and serum collection. Intergroup differences in liver index, fasting blood glucose (FBG), triglycerides (TG), interleukin (IL)-18, IL-10, malondialdehyde (MDA), and histopathological features were assessed by independent samples t-test (normal vs. model), one-way ANOVA (model vs. treatments), and least significant difference t-test (pairwise comparisons); correlations were assessed by Pearson's correlation coefficient.</p><p><b>RESULTS</b>Compared with the normal group, the model group showed significantly higher liver index (t=-2.327), FBG (t=-3.482), TG (t=-0.302), and serum IL-18 (t=-2.704) (all P less than 0.05), but significantly lower IL-10 (t=2.622, P less than 0.05); the MDA level was also higher in the model group, but the difference was not significant (t=-1.083, P less than 0.05). Livers from the model group showed obvious histological features of inflammation (lymphocyte and neutrophil infiltration) and steatosis (cytoplasmic lipid droplets). Inflammation was positively correlated with IL-18 (P less than 0.05), but negatively correlated with IL-10 (P less than 0.05), while steatosis was negatively correlated with IL-10 (P less than 0.05). Compared to the model group, quercetin treatment (both low- and high-dose) led to significant decreases in the liver index, FBG and IL-18 (all, P less than 0.01), and significant increase in IL-10 (P less than 0.05); however, the changes in liver index, FBG and IL-10 were not significantly different between the low- and high-dose treatment groups, but the high-dose of quercetin did induce a significantly greater decrease in IL-18 than the low-dose (P less than 0.05).</p><p><b>CONCLUSION</b>NAFLD rats have higher serum levels of IL-18 but lower levels of IL-10 than their healthy counterparts, and these differential cytokine expressions may be related to liver inflammation and steatosis. Quercetin treatment may help to delay the progression of NAFLD, possibly by adjusting the balance of inflammatory cytokines.</p>

Application of multi-coeffieient of variation significance test for toxicology study / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To establish the methods of calculating and analyzing the multi-coefficient of variation significance test for the toxicology study.</p><p><b>METHODS</b>The paper aimed to confirm the significance level with the method of Bonferroni and then compared the methods of calculating and analyzing of the experiment groups with the control group respectively.</p><p><b>RESULTS</b>The significance level of multi-coefficient of variation significance test was confirmed as alpha1=0.0167. Compared with the control groups, the activity of ALT in serum both in 30 mg/kg and 60 mg/kg groups did not change in the average significance test, which was not statistically significant (P>0.05), while it changed in the variation significance test, which was of statistical significance (P<0.0167). The activity of AST in serum in 60 mg/kg group did not change in the average significance test (P>0.05), while it changed in the variation significance test (P<0.0167).</p><p><b>CONCLUSION</b>The complete changes of the indexes can only be shown by use of both the average significance test and the variation significance test together.</p>