Effect Of Soyasaponins On Blood Lipid Metabolism Rats

Cerebrovascular and cardiovascular diseases severely harm human health,the basic pathogenic of which is the disorder of lipid metabolism, especially the high level of blood cholesterol, How to regulate the blood lipid effectively is a hotspot in nutriology research.The basic pathologis of cerebrovascular and cardiovascular diseases is atherosclerosis(AS) and dyslipidemia is closely correlated with cardiovascular disease. Lipid metabolism dysfunction induced AS is the important risk factor in the occurrence and development of cerebrovascular and cardiovascular diseases.Hyperlipidemia is always accompanied with hypercoagulate state. It was indicated that endothelial cell damage and endothelial dysfunction mostly participate in the process of atherogenesis. High level of LDL in plasma,especially oxidized LDL(OX-LDL) can damage endothelial cell, which allows atherogenic lipoprotein to deposit in the subendothelial space easily, endothelial dysfunction can disturb the balance between vasodilation and vasoconstriction,and promote or exacerbate the vessel wall damnification and atherogenesis. Lipid peroxidation plays an important role in the occurrence of AS. It was showed that the main reason is that lipid peroxidation reaction can cause contraction of endothelial cell and injury of cytoarchitecture(especially biomembrane system)and the production of lipid peroxide(LPO)can change the lipid composition of cell membrane and denature the cell membrane enzymes and proteins,which result in the destruction of the structure andfunction of cells.Therefore,the research on the harmful effects of lipid peroxidation attract people attention gradually.Soyasaponins(SS) are kinds of biologically active substances extracted from soy in recent years. Some investigators have reported that Soyasaponins regulates blood lipid by reducing serum concentration of total cholesterol(TC)and triglycerol(TG). Others indicate that SS can eliminate and promote intestinal cholesterol degradation.So we speculate that SS may be a radical scavenging agent and possess lipid lowering effect through antioxidation and modulating cholesterol metabolism in vivo.There are some reports related to blood lipid modulating effect by oligosaccharides, but both domestic and abroad researches paid more attention to oligofructose and inulin , But less attention has been paid to the dose of SS, Especially the different dosage of SS used for improving dyslipidemia has not been reported in any literatures.Many documents report that SS displays a strong activity of pulse.The purpose of the study was to establish lipid-rich diet induced hyperlipemia rat model,and observe the influence of SS on blood lipid,lipoprotein and apolipoprotein(apo)levels in rats, further explore the related mechanism of SS different dosage for the prevention and cure of AS in terms of vasoactive substances,hemorheology change,antioxidative activity and cholesterol metabolism,especially the influence of SS cooperative intervention on lipid metabolism in hyperlipidemic rats. Through determination of plasma thromboxane A2(TXA2),prostacyclin(PGI2),nitric oxide(NO),fecal bile acid excretion. In this study, sixty healthy male SD rats(260-300g)were randomly divided into five groups, with 12 rat each group, they were fed with normal diet(normal control group,ND),high fat diet(high fat control group,HFD),HFD diet+0.05mg/100g SS(experimentâ… group),HFD diet+0.10mg/100g SS(experimentâ…¡group),and HFD diet+0.15mg/100g SS (experimentâ…¢group)for 4 and 8 weeks respectively. Rat blood was collected from the eye veins or femoral veins for preparing serum and plasma after rats were fasted for 12 hours at themiddle or end of the experiment and rat livers were excised for histopathologic observation at the end of the experiment.Serum levels of TC,TG,VLDL-TG,LDL-C and HDL-C were measured with enzymatic reaction,and the levels of apoAI,B,C and E in serum were measured with immunity nephelometry.We observed lipid droplets in liver with light microscopy after HE .The Plasma levels of PGI2 and TXA2 in plasma were measured with radio-immunity technique and the plasma in level of NO with nitrate reductase technique.Viscosity of whole blood at high and low shear rate(H-WBV and L-WBV),plasma specific viscosity(PSV),blood reduced viscosity(BRV)and hematocrit(HCT)were also measured to observe effects of SS on vasoactive substances;the content of fecal bile acid was detected by phosphomolybdic acid colorimetric analysis to observe the effect of SS on cholesterol metabolism in vivo.Atherosclerosis index(AI)was calculated according to Fridewaid formula:AI=LDL-c/HDL-c.The main results and conclusions are summarized as follows:1. 10%Lard,2%cholesterol and 1%bile salt were added to rats diet,to establish mixed hypercholesterolemia model mainly caused by endogenetic cholesterol.Serum the concentration of TC and TG in serum measured at the middle of the experiment showed an obviously high level induced by lipid-rich diet fed with rats,which indicated that hyperlipidemic rat model has been successfully established.2. Intervention with experimentâ… ,experimentâ…¡and experimentâ…¢remarkably lowered the rat serum levels of TG,TC,VLDL-TG and LDL-C and AI value,while significantly increased the serum level of HDL-C;remarkably lowered the rat plasma levels of apoB,C,E ratio,while significantly increased the plasma level of apoAI. The result indicates that SS can promote lipid metabolism and improve dyslipidemia effectively through regulatingblood lipid,lipoprotein and apolipoprotein levels.3. Hyperlipidemia influences vasoactive substances obviously,while SS can decrease the plasm content of TXA2 and PGI2,and increase plasm contents of NO significantly,indicating that SS improve endothelial function,which helps to prevent AS and CHD.4. Through decreasing H-WBV,L-WBV,PSV,BRVand HCT,SS can improve hemorheology obviously.The result indicates that experiment group can alleviate hyperviscosity state,subsequently preventing blood lipid deposit on the vascular wall by improving erythrocyte deformative ability andlowering erythrocyte aggregation.5. HFD group rat liver cell occurrence obviously adipose degeneration ,Soyasaponins can be obviously inhibition liver cell damage due to cause of hypertriglyceridemia.Taken together,our study confirms that Soyasaponins are able to decrease serum levels of TG,TC,VLDL-TG,LDL-C and AI value,while increase HDL-C remarkably;decrease plasma levels of apoB,C,E and apoB/apoA-1 ratio,while increase apoA-1 significantly,effectively modulating dyslipidemia.SS improve vasoactive substances and hemorheology to prevent AS and cardiovascular diseases.