ABSTRACT
Aims: The aim of this experiment is to study the effect of flaxseed on lipid profile, antioxidant activity and ATP-cassette binding proteins G5 and G8 (ABCG5 and G8) levels in the liver of diabetic rat. Place and Duration of Study: Department of Biochemistry and Physiology Research Centre, Afzalipour School of Medicine, Kerman University of Medical Sciences(Kerman, Iran), between 2008 and 2011. Methodology: rats randomly were divided into three groups: diabetic rat + flaxseed (treatment group), diabetic rat (control group I), healthy rat (control group II). Afterward one month Serum lipid parameters and also Super oxide dismutase (SOD) activity, reduced glutathione (GSH) and malondialdehyde (MDA) levels were measured. ABCG5 and ABCG8 levels were determined by RT-PCR. Results: Flaxseed markedly reduced malondialdehyde (MDA), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), very low density lipoprotein cholesterol (VLDL-C) (all of them P<0.05). GSH, SOD (P<0.05) as well as liver ABCG5 and ABCG8 were significantly increased (P<0.01) in flaxseed treatedanimals compared with diabetic group. Conclusion: The results of this experiment showed that flaxseed has antioxidant and ani-atherogenic effect. This plant reduced cholesterol levels may be via ABCG5 and ABCG8 transporters in diabetic rats.
ABSTRACT
Some compounds in the garlic inhibit cholesterol synthesis, resulting in lowering of serum cholesterol and triglycerides and increase in HDL level. However, the mechanism of this specific effect is not fully understood. In the small intestine, ATP-binding cassette transporters G5, G8 and A1 (ABCG5, ABCG8 and ABCA1), as well as Niemann-Pick C1 like 1 (NPC1L1) protein have important roles in cholesterol metabolism. In this study, we evaluated the beneficial effect of aqueous extract of garlic on lipid profile and also expression of npc1l1, abca1, abcg5 and abcg8 genes in the intestine of N-Marry mice fed a high cholesterol diet as a possible mechanism of garlic effect. Twenty-four mice were randomly divided into three groups: Group 1: hypercholesterolmic (received chow + 2% cholesterol + 0.5% cholic acid); Group 2: garlic (received chow + 4% (w/w) garlic extract + 2% cholesterol + 0.5% cholic acid); and Group 3: received chow only. After one month, mice were anesthetized and blood was collected from their heart. The jejunum was removed, washed with PBS and entrocytes were scraped and used for the experiments. Serum lipids were measured enzymatically and expression of mRNA levels for the above-mentioned proteins was determined by semi-quantitative RT-PCR. Garlic extract significantly reduced serum lipids (p<0.05), compared with the hypercholesterolemic group. Expression of the intestinal npc1l1 was significantly decreased (p<0.01) in the garlic group, compared with the chow group, while abcg5 (p<0.01), abcg8 (p<0.01) and abca1 (p<0.05) expressions were significantly increased. In conclusion, this study reveals a possible mechanism for the beneficial effects of the garlic in lowering serum lipids by decreasing the intestinal lipid absorption and increasing excretion of cholesterol back into the intestinal lumen.