Effect of long-term ingestion of weakly oxidized flaxseed oil on biomarkers of oxidative stress in LDL-receptor knockout mice.

Key Findings

The objective of the study was to evaluate the effect of long-term consumption of weakly oxidized PUFA from flaxseed oil on in vivo oxidative stress, using an animal model currently applied to investigate atherosclerosis. The data showed that the long-term consumption of flaxseed oil containing weakly oxidized ALA and LA can promote oxidative stress in LDLr mice, measured as liver MDA concentration. Taking into account the trends to replace pro-inflammatory SFA or n-6 fatty acids with anti-inflammatory n-3, the study highlights that oils rich in PUFA must be strongly protected from oxidation during their processing and storage. In addition, the diet used in this study represents an improvement in the current model systems and can be applied in future investigations involving antioxidants and atherosclerosis.

Abstract

The effect of oxidized fatty acids on atherosclerosis progression is controversial. Thus, our objective was to evaluate the effect of long-term consumption of weakly oxidized PUFA from flaxseed oil on oxidative stress biomarkers of LDL-receptor mice. To test our hypothesis, mice were separated into three groups. The first group received a high-fat diet containing fresh flaxseed oil, the second was fed the same diet prepared using heated flaxseed oil, and the third group received the same diet containing fresh flaxseed oil and had diabetes induced by streptozotocin. Oxidative stress, aortic parameters and non-alcoholic fatty liver disease were assessed. After 3 months, plasma lipid profile, glucose levels, body weight, energy intake and dietary intake did not differ among groups. Likewise, oxidative stress, plasma malondialdehyde, hepatic MDA expressed as mmcl/mg portion and antioxidant enzymes did not differ among the groups. Hepatic linoleic acid, a-linolenic acid, arachidonic acid and EPA acid declined in the OXID and CONT + groups. Arctic wall thickness, lumen and diameter increased only in the OXID group. OXID and CONT + groups exhibited higher concentrations of MDA, expressed as umol/mg ptn per % PUFA, when compared with the CONT- group. Our results suggest that ingestion of oxidized flaxseed oil increases hepatic MDA concentration and is potentially pro-atherogenic. In addition, the mean MDA value observed in all groups was similar to those reported in other studies that used xenobiotics as oxidative stress inducers. Thus, the diet applied in this study represents an interesting model for further research involving antioxidants.