Impact of whole grain compound on insulin resistance and level of lipocalin-2 in rats fed with high fat/cholesterol diets

Objective To explore the effect of whole grain compound on insulin resistance and level of lipocalin-2(LCN-2)in liver and epididymal adipose tissues of rats fed with high fat/cholesterol diets.Methods Forty Sprague-Dawlay rats were randomly divided into control group,model group,white rice/processed wheat starch group,and whole grain compound group.All groups were given different experimental diets for 8 weeks.The serum fasting blood glucose(FBG) and fasting insulin(FINS)were measured and homeostasis model assessment of insulin resistance(HOMA-IR)was calculated.Protein expression of LCN-2 and peroxisome proliferator-activated receptor-γ(PPAR-γ)in liver and epididymal adipose tissues were analyzed by western blotting.Results The insulin resistance model of SD rats was successfully established.Compared with the control group,serum FBG and FINS levels were significantly increased in white rice/processed wheat starch group and model group(P<0.05).HOMA-IR values of white rice/processed wheat starch group and model group were 10.39±1.63 and 10.34±1.36.The rats fed with whole grain compound diet showed a decreased HOMA-IR level(6.81±1.37)compared with white rice/processed wheat starch group and model group.Protein expression of LCN-2 in whole grain compound group was significantly lower than those of other two groups,too.However,the level of PPAR-γin whole grain compound group was higher than that of other two groups.Conclusion Whole grain compound could improve glucose metabolism and insulin sensitivity through activating protein expression of PPAR-γand reducing relative level of LCN-2 in the liver of rats.