Liver Lipid Composition and Antioxidant Enzyme Activities of Spontaneously Hypertensive Rats After Ingestion of Dietary Fats (Fish, Olive and High-Oleic Sunflower Oils)

Abstract

Hypertension is associated with greater than normal lipoperoxidation and an imbalance in antioxidant status, suggesting that oxidative stress is important in the pathogenesis of this disease. Although many studies have examined the effect of antioxidants in the diet on hypertensión and other disorders, less attention has been given to the evaluation of the role of specific dietary lipids in modulating endogenous antioxidant enzyme status. Previously, we have described that liver antioxidant enzyme activities may be modulated by consumption of different oils in normotensive rats. The purpose of the present study was to examine the effects of feeding different lipidic diets (olive oil, OO, high-oleic-acid sunflower oil, HOSO, and fish oil, FO) on liver antioxidant enzyme activities of spontaneously hypertensive rats (SHR). Plasma and liver lipid composition was also studied. Total triacylglycerol concentration increases in plasma and liver of animals fed on the HOSO and OO diets and decreases in those fed on the FO diet, relative to rats fed the control diet. The animals fed on the oil-enriched diet show similar hepatic cholesterol and phospholipid contents, which are higher than the control group. Consumption of the FO diet results in a decrease in the total cholesterol and phospholipid concentration in plasma, compared with the high-oleic-acid diets. In liver, the FO group show higher levels of polyunsaturated fatty acids (PUFA) of the (n - 3) series, in relation to the animals fed on the diets enriched in oleic acid. Livers of FO-fed rats, compared with those of OO- and HOSO-fed rats showed: (i) significantly higher activities of catalase, glutathione peroxidase and Cu/Zn superoxide dismutase; (ii) no differences in the NADPH-cytochrome c reductase activity. The HOSO diet had a similar effect on liver antioxidant enzyme activities as the OO diet. In conclusion, it appears that changes in the liver fatty acid composition due mainly to n - 3 lipids may enhance the efficiency of the antioxidant defence system and may yield a benefit in the hypertension status. The two monounsaturated fatty acids oils studied (OO and HOSO), with the same high content of oleic acid, but different content of natural antioxidants, had similar effects on the antioxidant enzyme activities studied.

Up-Regulation of Mitochondrial Antioxidant Superoxide Dismutase Underpins Persistent Cardiac Nutritional-Preconditioning by Long Chain n-3 Polyunsaturated Fatty Acids in the Rat

“…Fish oil induced increases in antioxidant expression and reduced lipid peroxidation products were also reported in hepatic and renal tissue of immune suppressed mice [ 29 , 30 ] and hepatic tissue of hypertensive rats [ 31 ], conditions associated with heightened oxidative stress. In those studies, the fish oil diets were effective independently of varied provision of high or low concentrations of natural antioxidants in comparative n -6 PUFA or MUFA enriched diets.…”

Effects of different dietary n-6/n-3 polyunsaturated fatty acid ratios on boar reproduction

“…One of the most important factors contributing to poor semen quality has been reported to be oxidative stress [ 31 ]. Reports showed that oxidative stress is associated with fatty acid oxidation, which directly affects the survival of sperm [ 52 , 53 ]. In the current study, it was found that gene expression related to fatty acid metabolism in spermatozoa was altered by changes in dietary n-6/n-3 ratios.…”

“…Specifically, the mRNA expression of FAD6, CPT-1, PPAR-α and CYP11A1 were up-regulated in T2 boars, which may be associated with sperm fatty acid metabolism or antioxidant capacity. It is well known that PUFA can improve the antioxidant capacity of sperm [ 10 , 54 ], which may further be related to a change of liver fatty acid composition and antioxidant capacity [ 52 ]. However, higher linoleic acid and arachidonic acid can cause the cascade reaction of lipid peroxidation and DNA damage of spermatozoa [ 53 ].…”

Gender Related Differences in Paraoxonase 1 Response to High‐fat Diet‐induced Oxidative Stress

“…Activities of the main antioxidant enzymes in the liver— catalase, glutathione peroxidase, and Mn‐superoxide dismutase—were also reduced in response to the cafeteria‐diet feeding in both male and female rats, thus accounting for the increased lipid and protein oxidation observed in this tissue and pointing to a greater oxidative damage in the liver. This impaired antioxidant status could be attributed to both the liver steatosis in cafeteria diet‐fed rats (data not shown) and the higher content of monounsaturated fatty acids in the cafeteria diet compared to standard diet (40,41,42). Although both serum PON1 and the liver antioxidant enzymes activities decreased with the cafeteria‐diet feeding, only serum PON1 response showed gender differences, thus suggesting a greater sensitivity of PON1 to the obese status.…”