Biochemical study on the effect of alpha-lipoic acid on lipid metabolism of rats fed high fat diet

Hyperlipidemia is a known risk factor for the development of cardiovascular disease including
atherosclerosis. The present study was carried to evaluate the protective effects of alpha-lipoic acid
against hyperlipidemia induced in rats fed high fat diet. Hundred male albino rats were divided into
four equal groups. Group I:(control normal group) rats fed on normal diet. Group II: (hyperlipidemic
group) rats fed hyperlipidemic diet (1% cholesterol, 0.5 % cholic acid and 5% hydrogenated fat/kg diet)
for 8 weeks. Group III :( hyperlipidemia +Alpha-lipoic acid group) rats fed hyperlipidemic diet and
treated with alpha-lipoic acid (54 mg/kg b.wt/day/ i.p). Group IV: (Alpha-lipoic acid group): normal
rats treated with alpha-lipoic acid (54 mg/kg b.wt/day/ i.p). Blood samples for serum separation were
used for total cholesterol (TC), triacylglycerol (TG), high density lipoprotein-cholesterol (HDL-c), low
density lipoprotein-cholesterol (LDL-c), very low density lipoprotein-cholesterol (VLDL-c),
phospholipids, glucose and insulin determination. In addition, liver tissue were processed for the
determination of L-Malondialdhyde (L-MDA), catalase (CAT), superoxide dismutase (SOD) and
reduced Glutathione (GSH). The obtained results revealed that, a significant increase in serum TC, TG,
HDL-c, LDL-c, VLDL-c, glucose and insulin resistance in addition to liver L-MDA concentrations were
observed hyperlipidemic rats. However, administration of alpha-lipoic acid exhibited a significant
decreased in all mentioned parameters. On the other hand, serum phospholipids, antioxidant enzymes
and GSH in liver tissue were significantly decreased in hyperlipidemic rats. Meanwhile, treatment with
alpha-lipoic acid to hyperlipidemic rats resulted in significant increase in liver CAT activity and GSH
concentrations. It could be concluded that, alpha lipoic acid has the potential in improving dyslipidemia
and oxidative stress and may exert some protective effect on atherosclerotic vascular change in
hyperlipidemic rats.