| Objective:To investigate whether the product confected mainly with phytosterol esters has the effects of lowering serum cholesterol, improving lipid metabolism of the hyperlipidemia rats, preventing hyperlipidemia or atherosclerosis from befelling or developing, through the gavage interference with the product towards the diet-induced hyperlipidemia rats.Methods:1. Rat model of Diet-induced hyperlipidemia:The control group fed with normal diet all through was selected randomly from all 80 healthy male Sprague-Dawley rats. However, the rest 70 rats were fed with high-cholesterol diets for 3 weeks to induce the diet-induced hyperlipidemia model.2. Grouping & handling:After the diet-induced hyperlipidemia model was set up successfully, the 70 hyperlipidemia rats were divided into 7 groups, based on the level of their serum total cholesterol (TC), 10 rats each group.They were fed with high-cholesterol diets unceasingly.At the same time, the rats in the 4 interference groups were respectivelyfed by gavage with the product confected mainly with phytosterol esters, which is dissolved in solvents of oil or emulsion, with the dose of 5ml/kg body weight per day, high-dose oil group (0.6g/ml), low-dose oil group (0.2g/ml), high-dose emulsion group (0.6g/ml) and low-dose emulsion group (0.2g/ml). However, the rats in the oil control group, the emulsion control group and the hyperlipidemia model group were correspondingly gavaged with arachis oil, saccharose ester emulsion and distilled water every day.Otherwise, the rats of the control group were gavaged with distilled water.3. Test Indexs:To observe the level of body weight (BW), the serum total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C), LDL-C/HDL-C, TG/HDL-C, atherosclerosis index (AI), the activities of the plasma lipoprotein lipase (LPL)and hepatic lipase ( HL), liver weight, hepatic index, the weight of fat around testicle or kidney, the ratio between the weight of fat around testicle or kidney and BW of rats and so on.Results:After four weeks of gavage with phytosterol esters, the level of the serum total cholesterol of rats in all the 4 interference groups was significantly lower than that before the experiment (P<0.01 or P<0.05), and the level of the serum triglycerides was also lower .The level of the serum high-density lipoprotein cholesterol of rats in the 4 interference groups was all evidently higher than that before the experiment (P <0.01) .The level of the serum low-density lipoprotein cholesterol of rats in high-dose oil group , low-dose oil group and high-dose emulsion group was evidently lower than that before the experiment (P<0.01) .LDL-C/HDL-C of rats inhigh-dose oil group , low-dose oil group and high-dose emulsion group was significantly lower than the hyperlipidemia model group (P<0.05) .TG/HDL-C of rats in high-dose oil group and low-dose emulsion group was lower than the hyperlipidemia model group evidently (P<0.05 ). Atherosclerosis index of rats in the 4 interference groups was all obviously lower than the hyperlipidemia model group(P <0.05) .After six weeks of gavage, the activities of the plasma lipoprotein lipase and hepatic lipase of rats in the hyperlipidemia model group, oil control group and emulsion control group was obviously lower than the control group, but the activities of the plasma LPL and HL in the 4 interference groups was all significantly higher than the hyperlipidemia model group (P <0.05) .The liver weight and hepatic index of rats in all interference groups were both evidently lower than the hyperlipidemia model group (P<0.05 ) . However, there were no significant differences among the 8 groups in some indexs including the level of body weight, the weight of fat around testicle or kidney, the ratio between the weight of fat around testicle or kidney and BW of the hyperlipidemia rats (P>0.05) .Conclusion:Gavage with the product confected mainly with phytosterol esters, which is dissolved in different solvents of oil or emulsion at the lever of high-dose or low-dose, could significantly decrease the serum lipid level of the hyperlipidemia rats, including the serum TC, LDL-C as well as AI . They could also heighten the level of HDL-C evidently, and decrease the serum TG, LDL-C/HDL-C and TG/HDL-C of the hyperlipidemia rats.Otherwise, the product could significantly heighten the activities of the plasma LPL and HL of the hyperlipidemia rats, depress their liver weight and hepatic index obviously and lighten the steatosis of their liver.The study demonstratesthat phytosterol esters have obvious effects of blood-fat-lowering.They can regulate the serum cholesterol level of the hyperlipidemia rats and prevent hyperlipidemia or atherosclerosis from befelling or developing. Meanwhile, they can up-regulating the level of plasma lipase activities, which might be one of the possible mechanisms of phytosterol ester's effects. |
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