Objective To study the effect of rosiglitazone maleate on the expression of Tanis mRNA in the liver tissue and the plasma level of interleukin-6(IL-6)in the rat. Methods 24 male Wistar rats were randomly divided into 3 equal groups: model group,trial group and control group.An insulin-resistance model was set up for each rat of both model group and trial group by feeding the animals on high sugar,high fat forage for 6 consecutive weeks.Rats of the control group were fed on routine chow.In the following 2 weeks,rats of the model group and trial group were given each 4 mg·kg~(-1) of placebo and rosiglitazone maleate,q.d.,respectively.The drugs were administered by gastrogavage.After the termination of the two-week treatment,rats of all 3 groups were subjected to a 12 h fasting and blood samples were collected for the determination of fasting blood glucose(FBG) and fasting blood insulin(FINS).The insulin-resistance index(IR) was calculated according to the Homa formula.The animals were then sacrificed and liver tissues were taken for the determination of the expression of Tanis mRNA with RT-PCR.The plasma IL-6 was determined with ELISA. Results The level of plasma IL-6 was significantly higher in rats of the model group than that in rats of the control group(P<0.
05).The expression of Tanis mRNA by the liver tissue in rats of the model group was also much higher than that in rats of the control group(P<0.05).The level of plasma IL-6 and expression of hepatic Tanis mRNA were significantly lower in animals of the trial group than those of the model group(P<0.05). It was shown by multivariate regression analysis that plasma IL-6 levels were positively correlated with FINS and Homa-IR(r_(1)=0.633,P=0.014;r_(2)=0.638,P=0.015).The expression of Tanis mRNA in the liver tissue was positively correlated with plasma IL-6,FINS and Homa-IR(r_(1)=0.606,P=0.022;r_(2)=0.651,P=0.012;r_(3)=0.584,P=0.028). Conclusion The high expression of Tanis mRNA in the liver tissue may be one of the mechanisms underlying insulin resistance and development of diabetes mellitus.Rosiglitazone maleate was shown to effectively mitigate insulin-resistance,lower the level of IL-6 and expression of Tanis mRNA in the liver tissue in rats.