Echium oil reduces atherosclerosis in apoB100-only LDLrKO mice

Abstract

Introduction: The anti-atherogenic and hypotriglyceridemic properties of fish oil are attributed to its enrichment in eicosapentaenoic acid (EPA; 20:5, n-3) and docosahexaenoic acid (DHA; 22:6, n-3). Echium oil contains stearidonic acid (SDA; 18:4, n-3), which is metabolized to EPA in humans and mice, resulting in decreased plasma triglycerides.

Objective: We used apoB100 only, LDLrKO mice to investigate whether echium oil reduces atherosclerosis.

Methods: Mice were fed palm, echium, or fish oil-containing diets for 16 weeks and plasma lipids, lipoproteins, and atherosclerosis were measured.

Results: Compared to palm oil, echium oil feeding resulted in significantly less plasma triglyceride and cholesterol levels, and atherosclerosis, comparable to that of fish oil.

Conclusion: This is the first report that echium oil is anti-atherogenic, suggesting that it may be a botanical alternative to fish oil for atheroprotection.

Figure 1. The effect of atherogenic diets on body weight and plasma lipid and lipoprotein concentrations

Eight week old B100-only LDLrKO mice were fed diets for 16 weeks consisting of 0.2% cholesterol and 10% of calories from PO, with an additional 10% from PO, EO, FO (n=11-16 mice per group). Periodically, body weights (A) were determined and blood was obtained to assay plasma TG (B) and TPC (C) by enzymatic assays. (D) At 16 weeks, a terminal blood sample was used to fractionate plasma by FPLC and measure plasma lipoprotein cholesterol distribution. Values are mean ±S.E.M. Results with different letters denote significant differences among diet groups (P<.05).

Figure 2. Echium oil reduces atherosclerosis

Mice were sacrificed and aortas were removed for atherosclerosis quantification (n=12-16 mice per group). (A) Representative aorta from each diet group with atherosclerotic lesions identified by white arrows. (B) Quantification of aortic surface lesion area. (C) Aortic total cholesterol (TC), free cholesterol (FC) and cholesteryl ester (CE), measured by gas-liquid chromatography. Values are mean ± S.E.M. Bars with different letters denote significant differences among diet groups (P<0.05). (D) Aortic root intimal area. Frozen sections (8 μm) of the aortic root were stained with Oil Red O and intimal area was quantified using Image Pro software in three sections from each mouse. Each point denotes the average intimal area (n=3 sections) per mouse, whereas the horizontal lines indicate the group mean ± SEM.