Lutein Alleviates Atherosclerosis Risk Factors In Rats On High-fat Diet

Objective: To evaluate the effects of lutein on the risk factor of atherosclerosisin rats on high-fat diet rats and to explore the underlying mechanisms.Method: We establish hyperlipidemia (HLP) model by high-fat diet. SD ratswere fed high-fat diet (HFD) for10days. Then hyperlipidemia rats weresupplemented with12.5,25,50mg/kg bw d lutein by irrigating stomach for45days.Insulin tolerance test were performed one week before the end of the experiment. Andthe serum levels of blood lipids, glucose, antioxidation and insulin were determinedand HOMA-IR and HOMA-β were calculated. Levels of hepatic lipids were measuredalso. Three rats liver was random selected to make biopsy with H&E and Oil-Red O.Results:1. Lutein influence general condition in HLP rats.(1) Lutein could improve food, calorie intake, Lee’s index and body weight inHLP rats. HFD+lut25group was significantly higher than that in rats on HFD (P<0.05). Lutein supplementation significantly tends to reduce the ratio of perinephritadipose tissue and abdominal adipose tissue over body weight in rats on HFD. Andthe more doses, the more reducing of ratio.(2) Lutein supplementation was significantly reduced glutamate pyruvatetransaminase (GPT) in HLP rats (P <0.05). But it is no effect to glutamateoxaloacetate transaminase (GOT).2. Lutein influence lipid metabolism in HLP rats.(1) Lutein had no significant effect on plasma lipid levels. In middle dosegroup, serum TC, TG and LDL-C have decreased.In low dose and high-dose group,serum HDL-C levels have a tendency to increase. (2) Lutein had no significant effect on liver TC levels, but the liver TG levels ofmiddle dose group decreased significantly (P <0.05).(3) H&E and Oil-Red O staining in liver tissue show that lutein supplement cansignificantly improve the hepatocyte fat deposition of Lipid metabolic disorders.3. Lutein influence insulin sensitivity in HLP rats.(1) Compared with rats on HFD, the level of fasting blood glucose wassignificantly reduced (P <0.05). Suppled with the increased dose of lutein, fastingserum insulin levels in hyperlipidemic rats have a reduction trend.(2) The results of ITT showed that the areas under the curves (AUC) of rats onhigh dose of lutein lower than that in rats on HFD. High dose of lutein might improveinsulin tolerance.(3) After fed high-fat with lutein, the HOMA-IR levels of rats has decreasedwith increasing concentration of lutein and the high dose group has significantdifferences (P <0.05).4. Lutein influence antioxidase in HLP rats.The level of SOD in serum of rats on HFD+lutein is lower than in rats on HFD(P <0.05). Lutein supplementation might improve oxidative stress of HLP.Conclusion:Increased dietary intake of lutein can improve dyslipidemia, insulin sensitivityand antioxidant levels in HLP rats. It explains that atherosclerosis risk factors havesignificantly improved by lutein. In addition, this time we also found that lutein could reducebody fat deposition in HLP rats. It shows that lutein may have protection in visceral obesity.