海参皂苷对脂肪肝大鼠胆固醇代谢的调节作用

REGULATION OF CHOLESTEROL METABOLISM BY SEA CUCUMBER SAPONINS IN RATS WITH FATTY LIVER

目的研究海参皂苷(sea cucumber saponins,SCS)对乳清酸诱导的大鼠非酒精性脂肪肝(nonalcoholic fatty liver disease,NAFLD)的改善及胆固醇代谢的影响。方法通过膳食乳清酸诱导产生NAFLD模型,将大鼠按体重随机分为正常对照(CN)、乳清酸模型(orotic acid,OA)、皂苷低剂量(0.01%SCS)、皂苷高剂量组(0.05%SCS)4组,饲喂10d后观察其血清、肝脏脂质及胆固醇代谢相关基因m RNA表达量。结果:相比对照组,模型组血清和肝脏中总胆固醇含量升高,喂食高剂量海参皂苷后,血清和肝脏总胆固醇浓度分别降低了27.0%(P<0.01)和24.7%(P<0.05)。海参皂苷显著抑制了胆固醇合成限速酶羟甲基戊二酸单酰辅酶A还原酶(HMG-Co A reductase)以及胆固醇调节元件结合蛋白-2(SREBP-2)的基因表达,但对低密度脂蛋白受体(LDLR)的基因表达无显著影响,对胆固醇7α-羟化酶(CYP7A)的基因表达并没上调。结论:海参皂苷可显著抑制肝脏胆固醇的合成,降低血中胆固醇浓度,改善乳清酸诱导的大鼠脂肪肝。

Objective To investigate the effect of sea cucumber saponins（SCS） on cholesterol metabolism in orotic acid-induced fatty liver in rats. Methods The non-alcoholic fatty liver disease（NAFLD） model was established by feeding orotic acid（OA） diets in rats. The rats were randomly assigned to four groups： control group, OA model group, OA ＋ 0.01% SCS group and OA ＋ 0.05% SCS group. After 10 days of feeding, serum and hepatic lipid concentrations and the expression of genes involved in cholesterol metabolism in the liver were measured. Results Compared to the controls, OA feeding increased serum and hepatic TC levels significantly. High-dose sea cucumber saponins（0.05% SCS） reduced serum and hepatic TC levels by 27.0%（P0.01） and 24.7%（P0.05）, respectively. The SCS（0.05%） attenuated m RNA levels of sterol regulatory element binding protein-2（SREBP-2） and HMG-Co A reductase in the liver, while LDLR m RNA levels was not reduced. Furthermore, SCS downregulated gene expression of cholesterol 7α-hydroxylase（CYP7A）. Conclusion The sea cucumber saponins are beneficial in improving fatty liver induced by orotic acid in rats. The mechnism may be ralated to the inhibition of cholesterol synthesis in the liver and reduction of serum cholesterol levels.