Protective effect of dietary flaxseed oil on bleomycin‐induced pulmonary fibrosis

Abstract

Dietary flaxseed oil, containing n‐3 fatty acids, has been previously found in our study to protect against bleomycin‐induced pulmonary fibrosis. This study further reported the time‐course effect and potential underlying mechanisms. Forty Sprague‐Dawley rats were assigned into four groups with either corn oil (15% w/w) or flaxseed oil (15% w/w) in the diet for one month prior to treating with bleomycin at 8 U/kg oropharyngeally. Half of the rats were sacrificed 7 days after bleomycin treatment, and the others were sacrificed 21 days after the treatment. Both interleukin‐6 (IL‐6), a protein associated with fibrotic inflammation in the lung, and renin, an enzyme related to renin‐angiotensin system, were examined by Western blot. The time‐dependent increase of IL‐6 and renin proteins in response to bleomycin treatment was significantly reversed by flaxseed oil diet. In addition, the profiles of fatty acids in both liver and kidney tissues as measured by lipidomics demonstrated a significant increase of n‐3:n‐6 ratio in flaxseed oil‐fed groups. These results indicated for the 1st time that n‐3 fatty acid‐enriched flaxseed oil might inhibit the formation of pulmonary fibrosis via suppressing inflammation and renin‐angiotensin system.