油菜花粉超临界二氧化碳萃取物对高脂血大鼠脂质代谢的影响

【作者】 涂文利；

【导师】 耿越；

【作者基本信息】 山东师范大学 ， 细胞生物学， 2005， 硕士

【摘要】 本项试验使用超临界二氧化碳萃取技术萃取油菜花粉中的脂质成分,研究萃取物对高脂血大鼠的降血脂效果。实验建立大鼠高脂血模型,大鼠随机分为六组:基础饲料对照组、高脂饲料对照组、阳性药物对照组、低剂量萃取物组、中剂量萃取物组和高剂量萃取物组。药物和花粉萃取物灌胃,四周后处死大鼠,检测血清和肝脏中脂质主要成分、脂质代谢中的LCAT 酶和HMG-CoA 还原酶活性、肝脏、血清中脂肪酸组分等指标,制作并观察组织病理切片。实验结果表明:油菜花粉超临界二氧化碳萃取物是以a-亚麻酸为主的不饱和脂肪酸油脂。与高脂对照组相比,不同含量的花粉萃取物可以不同程度的降低高脂血大鼠血清中TG 和TC 水平;降低肝脏中TC 水平,明显升高肝脏HDL-C 和apoAI 水平,油菜花粉萃取物三个剂量组对大鼠肝脏LDL-C 和apoB 降低效果不同,显著降低大鼠肝脏中游离胆固醇水平(P<0.05);花粉萃取物组能升高大鼠血清LCAT 水平,抑制HMG-CoA 还原酶活性;花粉萃取物肝脏脂肪酸中DHA 含量明显高于高脂对照组。由HE 染色和苏丹Ⅲ染色观察结果来看,高脂血症大鼠肝脏细胞呈高度脂肪病变,而油菜花粉萃取物各剂量组大鼠肝脏细胞脂变明显减轻。在本实验中使用的花粉萃取物剂量并没有增加大鼠机体的脂质过氧化代谢产物MDA 的含量,表明富含α-亚麻酸的油菜花粉萃取物并没有增加脂质过氧化反应。由实验结果可以初步认为:油菜花粉对高血脂大鼠血脂的降低作用,可能是通过增加HDL-C 和LCAT 水平,促进胆固醇转运、代谢和排出,抑制HMG-CoA 还原酶活性,减少胆固醇体内合成,并更多还原

【Abstract】 Objective: The study aimed to evaluate the effects on lipid profiles in hyperlipidemic rats of rape pollen extract enriched with ALA using supercritical carbon dioxide extraction (SCE). Research Methods & Procedures: The experimental hyperlipidemic rats were established by providing with high fat diets, randomized into six groups, assigned to three doses of pollen extract, lovastatin, basic diet or fat diet. After four weeks of intragastric administration, the rats were executed, lipid levels and fatty acids component of serum and hepatic tissue were determined, also metabolic enzyme of lipid such as LCAT and HMG-CoA reducase were measured. Results: Total cholesterol and triacylglycerol levels in serum were significantly lower in pollen extract groups and medicinal control (MC) group than in high fatty control (HFC) group. Hepatic total cholesterol levels were decreased in rats fed pollen extract and lovastatin. A higher concentration of HDL-Cholesterol and apoAI in hepatic tissue were observed after intake of pollen extract compared to the HFC group (P<0.05). LCAT activity in serum of pollen extract groups was significantly higher than HFC group and HMG-CoA reductase showed decreasing tendency in groups of pollen extract. The contents of DHA in hepatic tissue in pollen extract groups were found higher than HFC group. Figures of H.E. waxed stain and Sudan Ⅲiced stain showed that hepatic cell of HFC group exhibited higher degree of fatty degeneration than other experimental groups. No significant changes of MDA were observed between HFC and other experimental pollen groups in this experiment,suggesting edible security of pollen extract. These results suggest that extract from rape pollen enriched in alpha-linolenic acid are effectively in decreasing the levels of lipid in plasma and hepatic tissue to various extent compared to high fats diet. This is possibly due to increasing level of HDL-C and activity of LCAT, decreasing activity of HMG-CoA reductase and the ratio of clearance of free cholesterol so as to promote transportation, excretion and metabolism of cholesterol in hepatic tissue and serum, also indirectly increasing in DHA concentration of hepatic tissue. Conclusion: Rape pollen extract enriched with alpha-linolenic acid is likely to be a novel agent capable of promoting a favorable lipid profile in hepatic tissue and serum. AlA is dietary essential fatty acid which is considered to be substitute for fish oil with regard to cardioprotectic benefit. Pollen extract contain not only the mainly component of ALA also other kind of complex substrates, therefore the lipid-lowing effects on serum and liver are carried out by ALA interacting with other natural product. The results are in accordance with many researches that consuming ALA from dietary show preventive effects against cardiovascular disease. Nevertheless some studies reported that intake of ALA is not associated with beneficial effect on cardiovascular heart diseases perhaps owing to various experimental animal and diets souse, diversified technology of processing as well as different trial designs. Further research should be conducted in the interest of steady safety usage when ALA is recommended in nutrition and clinical field.更多还原