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

Abstract

BackgroundCanola 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.MethodMale 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.ResultsCanola oil ingestion significantly decreased the life span of SHRSP rats compared with soybean oil, 85.8 ± 1.1 and 98.3 ± 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.ConclusionIn 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.

The effect of short-term canola oil ingestion on oxidative stress in the vasculature of stroke-prone spontaneously hypertensive rats

“…Our recent study strengthened this finding, and showed that canola oil ingestion reduced the lifespan of SHRSP rats compared to soybean oil following 1% NaCl loading, 85.8 ± 1.1 and 98.3 ± 3.4 days, respectively [8]. …”

Effects of Oxidative Stress on Vascular Reactivity in the Offspring of Protein-Restricted Stroke-Prone Spontaneously Hypertensive Rats

“…We have previously reported that the SHRSP offspring of protein-restricted dams showed enhanced salt sensitivity, together with a rapid increase in blood pressure and a shortened lifespan. 5) In terms of the relationship between salt loading and oxidative stress, Papazzo et al 22) have reported that the GSH-Px activity in red blood cells and the malondialdehyde levels in red blood cells and plasma were greater in SHRSP fed a diet containing canola oil and high salt than in SHRSP fed a diet containing canola oil lacking salt. These results indicate that ROS and lipid peroxidation were involved in worsening of the vascular dysfunction and/or the injury induced by salt loading in SHRSP.…”

Salt Loading in Canola Oil Fed SHRSP Rats Induces Endothelial Dysfunction

“…This data is consistent with our lifespan study data, where we showed a decrease in RBC SOD and catalase, however, RBC GPx was also reduced at the end of life. [7] Furthermore, the results from the previous lifespan study did not find any changes in the activities of the RBC antioxidants in the soybean oil group. [7] RBCs are under constant exposure to ROS and oxidative stress due to their role in transporting oxygen and carbon dioxide, and their increased content of heme iron.…”

“…[7] Furthermore, the results from the previous lifespan study did not find any changes in the activities of the RBC antioxidants in the soybean oil group. [7] RBCs are under constant exposure to ROS and oxidative stress due to their role in transporting oxygen and carbon dioxide, and their increased content of heme iron. [20] Therefore, the oxidative/antioxidant balance can become altered.…”

“…[1][2][3][4][5][6] We have previously shown that canola oil ingestion reduces the lifespan of SHRSP rats compared to soybean oil following 1% NaCl loading, 85.861.1 and 98.363.4 days, respectively. [7] The SHRSP rat is a model of human essential hypertension and stroke. [3] It is often used to model metabolic disease in humans and understanding the mechanism by which canola oil reduces life span is of significant importance.…”