Differential effects of dietary canola and soybean oil intake on oxidative stress in stroke-prone spontaneously hypertensive rats

Background: Canola oil shortens the life span of stroke-prone spontaneously hypertensive (SHRSP) rats compared with rats fed soybean oil when given as the sole dietary lipid source. One possible mechanism leading to the damage and deterioration of organs due to canola oil ingestion is oxidative stress. This study investigated the effect of canola oil intake on oxidative stress in this animal model.Method: Male SHRSP rats, were fed a defatted control diet containing 10% wt/wt soybean oil or a defatted treatment diet containing 10% wt/wt canola oil, and given water containing 1% NaCl. Blood pressure was measured weekly. Blood was collected prior to beginning the diets and at the end of completion of the study for analysis of red blood cell (RBC) antioxidant enzymes, RBC and plasma malondialdehyde (MDA), plasma 8- isoprostane and plasma lipids.Results: Canola oil ingestion significantly decreased the life span of SHRSP rats compared with soybean oil, 85.8 &plusmn; 1.1 and 98.3 &plusmn; 3.4 days, respectively. Systolic blood pressure increased over time with a significant difference between the diets at the 6th week of feeding. Canola oil ingestion significantly reduced RBC superoxide dismutase, glutathione peroxidase and catalase activities, total cholesterol and low-density lipoprotein cholesterol compared with soybean oil. There were no significant differences in RBC MDA concentration between canola oil fed and soybean oil fed rats. In contrast, plasma MDA and 8-isoprostane concentration was significantly lower in the canola oil group compared to the soybean oil group.Conclusion: In conclusion, canola oil ingestion shortens the life span of SHRSP rats and leads to changes in oxidative status, despite an improvement in the plasma lipids.<br /

Salt loading in canola oil fed SHRSP rats induces endothelial dysfunction

This study aimed to determine if 50 days of canola oil intake in the absence or presence of salt loading affects: (1) antioxidant and oxidative stress markers, (2) aortic mRNA of NADPH oxidase (NOX) subunits and superoxide dismutase (SOD) isoforms and (3) endothelial function in SHRSP rats. SHRSP rats were fed a diet containing 10 wt/wt% soybean oil or 10 wt/wt% canola oil, and given tap water or water containing 1% NaCl for 50 days. Without salt, canola oil significantly increased RBC SOD, plasma cholesterol and triglycerides, aortic p22phox, NOX2 and CuZn-SOD mRNA, and decreased RBC glutathione peroxidase activity. With salt, canola oil reduced RBC SOD and catalase activity, LDL-C, and p22phox mRNA compared with canola oil alone, whereas plasma malondialdehyde (MDA) was reduced and RBC MDA and LDL-C were higher. With salt, the canola oil group had significantly reduced endothelium-dependent vasodilating responses to ACh and contractile responses to norepinephrine compared with the canola oil group without salt and to the WKY rats. These results indicate that ingestion of canola oil increases O2 - generation, and that canola oil ingestion in combination with salt leads to endothelial dysfunction in the SHRSP model

Postexercise muscle cooling enhances gene expression of PGC-1α

This study aimed to investigate the influence of localized muscle cooling on postexercise vascular, metabolic, and mitochondrial-related gene expression

Real-time PCR primer sequences for genes of interest.

<p>The primers were all obtained from previous published sequences and were ordered through Geneworks (Australia): NOX2,<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0066655#pone.0066655-Reinehr1" target="_blank">[38]</a> p22^phox,<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0066655#pone.0066655-Cediel1" target="_blank">[36]</a> CuZn-SOD, MnSOD and Ec-SOD.<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0066655#pone.0066655-Chabrashvili1" target="_blank">[37]</a>.</p

Blood biochemistry in SHRSP rats fed canola oil for 50 days compared with soybean oil diets in the absence and presence of NaCl loading.

<p>Values are means ± SEM. ^†<i>P</i><0.05 represents a significant difference between canola oil and soybean oil with salt groups; ^#<i>P</i><0.05 represents a significant difference from canola oil no salt group; ^‡<i>P</i><0.05 represents a significant difference from soybean oil and canola oil no salt groups. *<i>P</i><0.05 represents a significant difference from soybean oil no salt group.</p

Cumulative concentration-response curves for norepinephrine (A), SNP (B) and ACh (C) in aortic rings from SHRSP and WKY rats.

<p>Values are mean ± SEM. *<i>P</i><0.05 represents a significant difference from soybean oil no salt; ^†<i>P</i><0.05 represents a significant different from canola oil and soybean oil with salt; ^#<i>P</i><0.05 represents a significant difference from canola oil no salt; ^‡P<0.05 represents a significant difference from canola oil with salt; ^Ω<i>P</i><0.05 represents a significant difference from all dietary groups; ^α<i>P</i><0.05 represents a significant difference from WKY rats.</p

Effect of 50 days of canola oil intake compared to soybean oil intake on mRNA expression in the aorta of SHRSP rats in the absence and presence of NaCl loading.

<p>Values are mean ± SEM. ^‡<i>P</i><0.05 represents a significant difference from soybean oil and canola oil no salt groups; *<i>P</i><0.05 represents a significant difference from soybean oil no salt group; ^#<i>P</i><0.05 represents a significant difference from canola oil no salt group.</p

Mean body weight of SHRSP rats fed canola oil compared with soybean oil diet in the absence or presence of NaCl loading.

<p>Vaules are means ± SEM.</p