Effect of tumor necrosis factor-alpha on resistin expression in 3T3-L1 adipocytes and its mechanism.

In order to investigate the effect of tumor necrosis factor-alpha (TNFalpha) on resistin expression in 3T3-L1 adipocytes, and further explore its mechanisms, the differentiated 3T3-L1 adipocytes were incubated with 0, 1, 10, 100 ng/mL TNFalpha respectively for 24 h, and then the expression of resistin was determined. The differentiated 3T3-L1 adipocytes were incubated with 100 ng/ mL TNFalpha for 3, 6, 24 h respectively, and then the expression of resistin mRNA was analyzed. 3T3-L1 adipocytes were induced to differentiate into mature adipocytes. The cells were randomly divided into 4 groups for culture. In the control group, no drugs were added. Cells of TNFalpha group were treated with 100 ng/mL TNFalpha. In Ro-31-8220 group, 5 micromol/L protein kinase C inhibitor Ro-31-8220 was added. With TNFalpha+Ro-31-8220 group, 100 ng/mL TNFalpha were added 1 h after the addition of 5 micromol/L Ro-31-8220. All adipocytes were cultured for 24 h. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were employed to detect the expression of resistin gene. Our results showed that resistin protein and mRNA in 3T3-L1 adipocytes were inhibited by TNFalpha at different concentrations (P<0.01), and the inhibitory effect increased with the concentration (P<0.01). At the same concentrations, the inhibitory effect increased with time (P <0.01). Ro-31-8220 could inhibit its expression and the inhibitive effect remained unchanged with addition of TNFalpha (P>0.05). It was concluded that TNFalpha could inhibit the expression of resistin in 3T3-L1 adipocytes. The mechanism may be that the expression of resistin is partly controlled by protein kinase C signal conduction pathway.