Abstract: Objective: To observe the effect of ω-3 polyunsaturated fatty acids (ω-3 PUFA) on nuclear factor (NF) -κB expression in the lung tissue of sepsis induced acute lung injury (ALI) rat model.Methods: Thirty experimental rats were randomly divided into three groups:healthy controls (A),sepsis group (B) and intervention group (C),ten in each.The sepsis ALI rat model of group B and C was established through cecal ligation perforation,and group C group nutritional support contains ω-3 PUFA through the jugular enous catheter.The expression of NF-κB in the lung tissue of three groups was detected by immunohistochemistry (ABC) and Western blot.Results: In group A,only a few scattered NF-κB nuclear positive cells were found;in group B,plenty of NF-κB nuclear positive cells were present in the airway mucous membrane,interstitial lung,alveolar space and endothelial cells (P<0.01);in group C,the quantity of NF-κB nuclear positive cells was higher than that in the control group,but decreased significantly than that in ALI group (P<0.01).Western blot results indicated that,the expression of NF-κB protein were exist in the three groups.Conclusions: ω-3 PUFA can decrease the protein expression of NF-κB in the lung tissue of sepsis induced ALI rat model.ω-3 PUFA could alleviate inflammation by inhibiting activation of NF-κB.