Establishment of the insulin resistance induced by inflammatory response in 3T3-L1 preadipocytes cell line

In the light of given recent reports, insulin resistance related to inflammation is characterized by increasing a diverse array of pro-inflammatory cytokines. In this study, hypothesizing that 3T3-L1 non-differentiated preadipocytes cell line as a cell model could be used to investigate this linkage, the aim is to determine whether the preadipocytes induced by different inflammatory responses could cause insulin resistance. This paper has determined the time and concentration-dependent effects of insulin on glucose consumption in the 3T3-L1 non-differentiated preadipocytes. Glucose consumption has also been assayed in the preadipocytes which are treated with LPS and CM originated from LPS-activated RAW264.7. Then protein level of each group has been measured by coomassie brilliant blue protein kit. Furthermore, secretion levels of IL-6 and TNF-alpha are measured by ELISA in the supernatant of RAW264.7 and preadipocytes. Finally, the mRNA expressions for IL-6, TNF-alpha and PPARgamma has been assessed by RT-PCR. The results show that administration of LPS and CM both can increase releases of IL-6 and TNF-alpha, as well as gene expression of IL-6 mRNA; this change is accompanied with suppression of PPARgamma mRNA activation in 3T3-L1 undifferentiated preadipocytes. In conclusion, our results suggest that in preadipocytes, pro-inflammatory cytokines can result in insulin resistance, and deserve further investigation to be helpful for treatment and revealing mechanisms of T2DM.