Dietary flaxseed oil decreases interleukin‐1 and alpha‐smooth muscle actin in a rat bleomycin‐induced fibrosis model

Abstract

Dietary fish oil, containing long chain ω‐3 fatty acids, has been previously found to protect against monocrotaline‐induced pulmonary fibrosis. This study is investigated the effects of ω‐3 fatty acids‐enriched flaxseed oil on bleomycin‐induced pulmonary fibrosis. Forty‐two Sprague‐Dawley rats were assigned into seven groups with various doses of flaxseed oil at 0, 2.5, 5, 7.5, 10, 12.5, and 15% (w/w) in the diet for one month prior to treating with bleomycin at 8 U/ kg oropharyngeally. Two weeks after bleomycin treatment, the rats were sacrificed and three proteins including TGF‐β, IL‐1, and α‐Smooth Muscle Actin (α‐SMA), commonly associated with fibrotic inflammation in the lung, were examined by Western blot. The amount of IL‐1 and α‐SMA decreased significantly as the amount of ω‐3 fatty acids increased, whereas TGF‐β did not change significantly. In addition, fatty acid profiles from the liver and lung tissues were analyzed by lipidomics, resulting an increased ratio of ω‐3:ω‐6 fatty acids in both tissues as the amount of flaxseed oil increased. These results indicated that the ω‐3 fatty acids in flaxseed oil inhibited the formation of pulmonary fibrosis in a dose‐dependent manner via anti‐inflammatory mechanisms, which appears associated with the modulated fatty acid composition in the tissues.