Effects Of Interleukin-6 And Pioglitazone On Visfatin MRNA Expression In 3T3-L1 Adipocytes

Objective To observe the effects of interleukin-6(IL-6) and pioglitazone on visfatin mRNA expression in 3T3-L1 adipocytes.Methods 3T3-L1 preadipocytes were cultured in vitro and differentiated into the matured adipocytes.IL-6 or pioglitazone with different concentrations was added into the culture medium of differentiated adipocytes for various time.Total RNA was extracted and visfatin mRNA expression was measured by semiquantitative RT-PCR technique to find the most suitable concentration and appropriate time respectively. Then the differentiated 3T3-L1 adipocytes were divided randomly into 5 groups: Control group:without any intervention;Pioglitazone group:with pioglitazone only; IL-6 group:with IL-6 only;Pioglitazone pretreatment group:after the pretreatment of pioglitazone for 1 hour,IL-6 was added after the withdrawl of pioglitazone;IL-6+ pioglitazone group:with IL-6 and pioglitazone together;All the groups mentioned above were treated with the most suitable dose,then we observed the visfatin mRNA expression after a period of appropriate time.Results Both groups expression level of visfatin mRNA were lower than the control group's when differentiated 3T3-L1 adipocytes were treated with IL-6 and pioglitazone respectively.In addition,it could result in statistical significance when the concentration of IL-6 reached a certain degree(≥3ng/ml),so could pioglitazone (≥10μmol/L).It produced no statistical significance though the visfatin mRNA expression level of pioglitazone pretreatment group or IL-6+pioglitazone group improved,compared with the IL-6 group.Conclusion IL-6 and pioglitazone both suppressed the visfatin mRNA expression in 3T3-L1 adipocytes.In our study,PPARγactivation by pioglitazone is not sufficient to reverse IL-6-induced visfatin downregulation.Downregulation of visfatin mRNA expression by IL-6 might play a role in the pathogenesis of the insulin resistance syndrome.Visfatin is not a target for TZD and,thus,is unrelated to the insulin-sensitizing effect of these drugs.