丹荷颗粒对高胆固醇血症大鼠肝脏超微结构及SREBP-1、LXRα、RXRA蛋白表达的影响

Effects of Danhe Granules on Liver Ultrastructure and SREBP-1,LXRα,RXRA Proteins Expression in Hypercholesterolemic Rats

目的观察丹荷颗粒对高胆固醇血症大鼠肝脏脂质沉积及相关蛋白表达的影响,探讨其保护肝脏的作用机制。方法36只雄性SD大鼠随机分为空白对照组、模型组、阳性药组(阿托伐他汀2.1mg/kg)和丹荷高、中、低剂量组(丹荷颗粒3.30、1.10、0.37g/kg),每组6只。除空白对照组外,其余大鼠予高脂乳剂灌胃12周+潮湿垫料饲养建立高胆固醇血症模型,空白对照组予纯净水灌胃+正常垫料饲养。第7周开始,造模同时各给药组予相应药物灌胃,空白对照组和模型组灌胃纯净水,至造模结束。计算大鼠肝重比,全自动生化分析仪检测血清总胆固醇(TC)、三酰甘油(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)、丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)含量,油红O染色观察肝组织脂质沉积,透射电镜观察肝细胞超微结构,Westernblot检测肝组织固醇调节元件结合蛋白1(SREBP-1)、肝X受体α(LXRα)、视黄醇X受体α(RXRA)蛋白表达。结果与空白对照组比较,模型组大鼠体质量、肝重比和血清TC、LDL-C、HDL-C、ALT含量显著升高(P<0.05,P<0.01),油红O染色面积比显著增加(P<0.01),肝细胞内脂滴增多,细胞核变小,线粒体变形,内质网结构模糊,肝组织SREBP-1、LXRα、RXRA蛋白表达显著升高(P<0.05,P<0.01);与模型组比较,各给药组大鼠体质量、肝重比和血清TC、LDL-C、HDL-C含量显著降低(P<0.05,P<0.01),油红O染色面积比显著减少(P<0.05,P<0.01),丹荷各剂量组血清ALT含量显著降低(P<0.05,P<0.01),丹荷高剂量组肝细胞脂滴减少,细胞核大小适中,线粒体完整,内质网结构清晰,肝组织SREBP-1、LXRα、RXRA蛋白表达显著降低(P<0.01)。结论丹荷颗粒可降低高胆固醇血症大鼠血清胆固醇,减少脂质沉积,其作用机制可能与下调SREBP-1、LXRα、RXRA蛋白表达,抑制肝脏脂质合成相关。

Objective To observe the effects of Danhe Granules on lipid deposition and related protein expression in liver of hypercholesterolemic rats;To explore its mechanism on protecting liver.Methods Totally 36 male SD rats were randomly divided into blank control group,model group,Danhe high-,medium-and low-dosage groups(Danhe Granules 3.30,1.10,0.37 g/kg),and positive drug group(atorvastatin 2.1 mg/kg),with 6 rats in each group.Except for the blank control group,the remaining rats were given high-fat emulsion by gavage for 12 weeks and moist padding to prepare a hypercholesterolemia model.The blank control group was given pure water by gavage and normal padding.Starting from the 7th week,corresponding drugs were administered to the medicated groups by gavage simultaneously during the modeling process,while pure water was administered by gavage to the blank control group and the model group until the end of modeling.The liver weight ratio of rats was calculated,the contents of serum total cholesterol(TC),triacylglycerol(TG),low-density lipoprotein cholesterol(LDL-C),high-density lipoprotein cholesterol(HDL-C),alanine aminotransferase(ALT),aspartate aminotransferase(AST)were detected.Oil red O staining was used to observe lipid deposition in liver tissue,and transmission electron microscopy was used to observe the ultrastructure of liver cells.Western blot was used to detect sterol regulatory element binding protein 1(SREBP-1),liver X receptorα(LXRα),and retinol X receptorα(RXRA)protein expressions in liver tissue.Results Compared with the blank control group,the body mass,liver weight ratio,and TC,LDL-C,HDL-C,ALT contents in serum of the model group significantly increased(P<0.05,P<0.01),the ratio of oil red O staining area increased(P<0.01),with increased lipid droplets in hepatocytes,relatively smaller nuclei,deformed mitochondria,and blurred endoplasmic reticulum structure,the expression of SREBP-1,LXRαand RXRA proteins in liver tissue of the model group significantly increased(P<0.05,P<0.01).Compared with the model group,the body mss,liver weight ratio,and TC,LDL-C,HDL-C contents in serum of Danhe groups and positive drug group significantly decreased(P<0.05,P<0.01),the ratio of oil red O staining area decreased(P<0.05,P<0.01),ALT content in serum of Danhe groups significantly decreased(P<0.05,P<0.01),lipid droplets decreased in Danhe high-dosage group,cell nuclei were moderate in size,mitochondria were intact,and endoplasmic reticulum structure was clear,and the protein expressions of SREBP-1,LXRαand RXRA significantly decreased(P<0.01).Conclusion Danhe Granules can decreased serum cholesterol and lipid deposition in hypercholesterolemic rats,and its mechanism of action may be related to downregulating SREBP-1,LXRαand RXRA protein expression and inhibition of liver lipid synthesis.