Doctor of Philosophy / Department of Human Nutrition / Richard C. Baybutt / Weiqun George Wang / Although omega-3 fatty acids have been a hot issue in nutrition for years, there remains a
paucity of research on the topic of omega-3 fatty acid and pulmonary fibrosis and the mechanism
is still unclear. The purpose of this research is to investigate the preventive effects of flaxseed oil
for bleomycin-induced pulmonary fibrosis in rats and to find the possible underlying
mechanisms. There are two experiments demonstrated in this dissertation, one is with various
doses of flaxseed oil in the diet (0, 2.5, 5, 7.5, 10, 12.5, and 15 % (w/w)), and the other is with
different times of sacrificing animals after oropharyngeal bleomycin treatment (days 7 and 21).
In the first study, three proteins including transforming growth factor-[beta] (TGF-[beta]),
interleukin-1 (IL-1), and [alpha]-smooth muscle actin ([alpha]-SMA), commonly associated with fibrotic
inflammation in the lung, were examined by Western blot and fatty acids composition of the
diets and tissues were analyzed by gas chromatography (GC). Fifteen percent of flaxseed oil
group significantly reduced septal and vascular thickness and fibrosis in the lung, and significant
cardiac fibrosis in the heart. The amount of IL-1 and [alpha]-SMA decreased significantly as the
amount of omega-3 fatty acids increased, whereas TGF-[beta] did not change significantly.
The next study further reported the time-course effect and potential underlying
mechanisms. 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 in response to bleomycin treatment was reversed by
flaxseed oil diet. Although renin was not significantly different in the kidney, it suggested that
the renin-angiotensin system may be involved locally. In addition, the profiles of fatty acids in
both liver and kidney tissues as measured by lipidomics demonstrated a significant increase of
omega-3: omega-6 ratio in the flaxseed oil-fed groups.
Overall, these results indicated for the first time that the omega-3 fatty acids rich in
flaxseed oil inhibited the formation of pulmonary fibrosis in a dose-dependent manner - however
the moderate dose of flaxseed oil was most effective - via anti-inflammatory mechanisms, which
appears associated with the modulated fatty acid composition in the tissues.
| Identifer | oai:union.ndltd.org:KSU/oai:krex.k-state.edu:2097/15106 |
| Date | January 1900 |
| Creators | Choi, Seojin |
| Publisher | Kansas State University |
| Source Sets | K-State Research Exchange |
| Language | en_US |
| Detected Language | English |
| Type | Dissertation |
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