Salt loading in canola oil fed SHRSP rats induces endothelial dysfunction

Area of Science:

• Cardiovascular Science
• Nutritional Biochemistry
• Toxicology

Background:

• Dietary fats significantly influence cardiovascular health.
• Oxidative stress and endothelial dysfunction are key factors in hypertension.
• Canola oil is widely consumed, but its effects under specific conditions warrant investigation.

Purpose of the Study:

• To investigate the impact of canola oil consumption on oxidative stress markers.
• To assess changes in aortic gene expression of NADPH oxidase (NOX) and superoxide dismutase (SOD) isoforms.
• To evaluate the effect of canola oil, with or without salt loading, on endothelial function in spontaneously hypertensive rats (SHRSP).

Main Methods:

• SHRSP rats were fed diets containing soybean oil or canola oil (10 wt/wt%) for 50 days.
• Rats received either tap water or 1% NaCl solution.
• Measurements included antioxidant/oxidative stress markers, aortic mRNA levels (NOX subunits, SOD isoforms), and endothelial function (vasodilation/contraction responses).

Main Results:

• Canola oil alone increased RBC SOD, plasma lipids, and aortic mRNA for p22 (phox), NOX2, and CuZn-SOD.
• Combined canola oil and salt intake reduced RBC SOD and catalase activity, altered LDL-C and MDA levels, and decreased p22 (phox) mRNA.
• Salt-combined canola oil significantly impaired endothelium-dependent vasodilation and contractile responses.

Conclusions:

• Canola oil ingestion promotes superoxide generation (O2 (-)).
• Concomitant intake of canola oil and salt induces significant endothelial dysfunction in the SHRSP rat model.
• These findings suggest potential cardiovascular risks associated with combined canola oil and high salt consumption.