Project Supported by Higher Education Institutions, 2009 - 2010
Investigation of Oxidized Low-Density Lipoproteins and Lipid Peroxidation in Experimentally Hyperlipidemia Induced Mice.
Hyperlipidemia is a major risk factor in atherosclerotic events. Low density lipoproteins (LDLs) are the main source of lipids in atherosclerotic plaques within foam cells. Oxidation of LDL is believed to play an important role in the development of atherosclerosis. Macrophages are considered to be precursors of foam cells, but they can not take up native LDL. Thus, measurement of oxidized LDL is essential for investigating its releavance to atherosclerotic diseases. In this study; oxidized LDL (ox-LDL), lipid peroxidation (LPO) and sialic acid values were investigated in experimental hyperlipidemia induced mice and the effect of apolipoprotein B–100 (Apo-B) and LDL conjugate on this values were examined.
Thirty two C57BL/6 mice were enrolled into the study. Mice were divided into four groups. Control group (n=8), hyperlipidemic group (n=8), hyperlipidemic + Apo-B group and hyperlipidemic+LDL group. Mice were sacrified at the end of two months. Blood samples and liver tissues were taken for routine lipid parameters, ox-LDL, LPO, glutathione (GSH) and sialic acid analysis.
Serum levels of total lipid, cholesterol, LDL-C significantly increased in hyperlipidemic group with respect to control group (p<0,001). LDL-C significantly decreased in both Apo-B and LDL conjugate given hyperlipidemic groups respectively (p<0.002, p<0,001). Serum ox-LDL and liver ox-LDL increased significantly in short term hyperlipidemia, the effects of Apo-B and LDL conjugates on ox-LDL levels was not in expected values. Lipid peroxidation in short term hyperlipidemia significantly increased in liver homogenates (p < 0,001). Apo-B and LDL conjugates affected this increased diffferently. Sialic acid values also increased in short term induced hyperlipidemia, there was no effect of Apo-B and LDL conjugates on sialic acid values.
In conclusion; in short term experimental hyperlipidemia ox-LDL, lipid peroxidation and sialic acid values increased. Oxidation of LDL in the early stages of hyperlipidemia should be taken into consideration for the therapeutic strategies.
Key Words: Apolipoprotein B, Lipid peroxidation, Low density lipoprotein, Oxidized low density lipoprotein, Sialic acid.