Supplementation of whole grain flaxseeds (Linum usitatissimum) along with high cholesterol diet and its effect on hyperlipidemia and initiated atherosclerosis in Wistar albino male rats

BACKGROUND AND AIM: Flaxseeds are known to have varying antihypercholesterolemic and antiatherogenic activity due to its lignan secoisolariciresinol diglucoside, alpha-linolenic acid, and omega-3 fatty acids. The beneficial effect of whole grain dietary flaxseed was evaluated experimentally in high cholesterol diet (HCD)-fed Wistar albino rats. MATERIALS AND METHODS: Male Wistar albino rats (200 g) were divided into four groups of 12 rats each. Group I rats kept as control and given basal rat chew diet, Group II as positive control for induction of hypercholesterolemia and atherosclerosis by addition of 1% cholesterol and 15% saturated edible oil to the 1000 g of standard rat chew diet (HCD), Group III rats fed with whole grain flaxseed powder at 7.5 g/kg of rat/day in the standard rat chew diet and kept as flaxseed control, and Group IV rats supplemented with flaxseed at 7.5 g/kg of rat/day along with HCD and maintained for 90 days. RESULTS: Group II rats revealed significantly (p<0.05) higher total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and very LDL-C and significantly (p<0.05) reduced levels of high-density lipoprotein cholesterol (HDL-C), whereas tissue antioxidants such as catalase, superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione S transferase (GST) were significantly (p<0.05) reduced, and lipid peroxidation products of thiobarbituric acid reactive substances (TBARS) level were nonsignificantly (p<0.05) increased in the heart and liver tissues. Flaxseeds supplementation along with HCD significantly ameliorated the serum levels of TC, TG, LDL-C, and HDL-C along with cellular antioxidant enzymes such as catalase, SOD, GPx, GR, GST, and non-significant amelioration of TBARS in the heart and liver tissues compared to Group II rats. Majority of the histopathologically initiated atherosclerotic changes in the aorta and fatty change in the liver of Group II were not observed in the flaxseed supplemented Group IV; however, interestingly proliferation of endothelial cells with new vascular channel formation in the liver and in between cardiac muscle fibers was observed in Group I and Group IV rats. CONCLUSION: The present study established the hypercholesterolemia with initiated atherosclerotic lesion in the aorta but unable to establish the atheromatous plaque in the aorta. Flaxseed supplementation along with HCD showed significant antihypercholesterolemic effect and ameliorated the changes of initiated atherosclerosis in the aorta. It needs further studies to explore all the possible beneficial effects and angiogenic properties of flaxseeds in the laboratory animals and human trials.