Dietary Flaxseed Oil Protects against Bleomycin-Induced Pulmonary Fibrosis in Rats
Figure 3
(a) Histological sections of rat lungs of the four groups sacrificed at day 2. Mild septal congestion and bronchial inflammatory reaction is found in rats treated with the vehicle and corn oil. Severe septal and bronchial inflammation and the increased presence of collagen (blue) are seen in bleomycin treated rats on the corn oil diet. Inflammation and vascular thickness are less severe when the diet is flaxseed oil. Stain: Masson’s Trichrome, 200X. (b) Histological sections of rat lungs of the four groups sacrificed at day 7. The VC-treated rat lungs show modest septal inflammation and a mild increase of adventitial edema and fibrosis. No damage was observed in VF treated rats. Bleomycin treated rats on the corn oil diet present diffuse inflammation and septal thickening, severe vascular thickening with markedly decreased lumen patency and bronchitis with increased presence of collagen (blue). Bleomycin treated rats on the flaxseed oil diet had less severe damage with not so prominent septal thickness, more patent arterial lumina and less fibrosis. Stain: Masson’s Trichrome, 200X. (c) Histological sections of rat lungs of the four groups sacrificed at day 21. The vehicle and corn oil caused diffuse septal and bronchial inflammation with increased collagen (blue) around the bronchial pulmonary arteries, and in the septa. No similar damage was observed in VF rats. Septal and bronchial inflammation is very severe in lungs of rats receiving bleomycin and on the corn oil diet, with vasculitis and fibrosis. The peribronchial arterioles were particularly involved with almost total obstruction of their lumen. Flaxseed oil diet markedly attenuated the bleomycin-induced damage both as septal inflammation and vasculitis. While the lungs of bleomycin + corn oil-treated rats were similar at 7 and 21 days, the lungs of bleomycin + flaxseed oil-treated rats were markedly improved at 21 days versus those of rats sacrificed after 7 days. Stain: Masson’s Trichrome, 200X. Abbreviations used: VC (vehicle, corn oil), VF (vehicle, flax seed oil), BC (bleomycin, corn oil), and BF (bleomycin, flax seed oil).
