Background

The adipose tissue plays an important role in obesity associated inflammation.PON1 is a potent antioxidant protein expressed in adipocytes and has a protective effect on inflammatory factor induced cell damage.Clinical study indicated that TNF level is elevated in visceral adipose tissue of obese patients and omega 3 fatty acids have beneficial effects on preventing inflammatory factor induced adipocyte dysfunction.However, the role of TNF on PON1 activity remains unclear.In this study, we investigated whether TNF could modulate PON1 activity and examine whether omega 3 fatty acid could prevent TNF mediated cell damage by modulating PON1 activity.

Methods

Differentiated 3T3-L1 adipocytes were treated with the omega 3 fatty acid for two hours and TNF was added for another 16 hours.PON1 expression was measured by Western blotting.The endogenous levels of phosphorylated ERK1/2, an active component of TNF signaling, was also measured.Student t test was used for statistical analysis, with p < 0.05 considered to be statistically significant.

Results

1) IL-1 slightly increases PON1 release but significantly decreases PON1 protein synthesis (P<0.05); 2) The omega 3 fatty acid had no direct effect on basal PON1 release or protein expression but significantly reversed TNF mediated decrease in PON1 protein expression (P<0.05); 3) Mechanism analysis indicates that TNF increased cellular p-ERK1/2 activity; 4) Omega 3 fatty acid significantly prevented TNF mediated increase in ERK1/2 activity.

Conclusions

Omega 3 fatty acid plays an anti-inflammatory role in adipocytes by preventing TNF mediated PON1 decrease through ERK ½ pathway.