粗壮女贞总苷降脂作用及其基于AMPK通路的降脂作用机制研究

摘要

目的 探讨粗壮女贞总苷(total phenylpropanoid glycoside from CN,CNTG)降脂作用及其基于AMPK通路的降脂作用机制.方法 Syrian金黄地鼠随机分为正常组、高脂模型组、阳性药非诺贝特组及CNTG高、中、低剂量组.除正常组外,其余各组地鼠应用高脂饲料诱导建立混合型高脂血症模型.造模1周后取血,检测血清 TC、TG、LDL-C、HDL-C含量,确定模型形成.之后连续给药4周,在给药2周、3周及4周后分别取血,检测血清中TC、TG、LDL-C和HDL-C的含量.在给药4周后剖取肝脏,进行肝脏TG、TC含量测定和肝脏病理学检测.并应用实时定量PCR检测CNTG对肝脏中AMPK、CD36、CPT1、ACC的mRNA表达的影响;用Western blot法检测AMPK和其上游调控蛋白LKB1的磷酸化蛋白和总蛋白水平,并检测HMG-CoA还原酶的蛋白表达量.结果 给药2周、3周、4周后,与模型组相比,CNTG高剂量组血清中的TC、TG、LDL-C含量均明显降低(P<0.05,P<0.01);肝脏中TC、TG含量明显降低(P<0.01);并可明显减轻肝细胞病变.实时定量PCR结果显示,与模型组相比,CNTG可以明显升高AMPK的相对表达量(P<0.01),但CD36、ACC和CPT1的相对表达量无明显变化.Western blot结果显示,与模型组相比,CNTG高剂量组肝脏中的LKB1、phospho-LKB1及phospho-AMPKα的相对表达量均提高(P<0.05),差异具有显著性.结论 CNTG能有效降低高脂血症金黄地鼠的血脂和肝脂水平,其机制可能是CNTG促进肝脏中LKB1磷酸化以激活AMPK,从而调控机体脂质代谢.%Aim To evaluate the hypolipidemic effect of total phenylpropanoid glycoside extracted from Ligustrum robustum(Roxb.)Blume(CNTG)and its mecha-nisms.Methods The 60 hamsters were randomly divided into six groups,namely the control group,the model group,the positive control group(fenofibrate,150 mg·kg-1),the high(1 200 mg·kg-1),medium(600 mg·kg-1)and low(300 mg·kg-1)doses of CNTG groups.Only the control group was given control diet and other groups received high-fat diet.The changes of serum lipid were measured and analyzed in 1st week to ensure the successful establishment of the model.The drugs were administered daily for four weeks and the concentrations of lipids were determined in the 2nd week,3rd week and 4th week respectively.Quantitative real-time PCR and Western blot were used to assay the mRNA and protein expression of related signaling enzymes and proteins.Results Compared with the model group,the concentrations of serum TG,TC,LDL-C(P<0.05,P<0.01)and hepatic TG,TC(P<0.01)were effectively reduced in hamsters in CNTG-treated groups.Mechanism research found that CNTG increased the levels of phospho-AMPKα,LKB1 and phospho-LKB1 in liver(P<0.05).Conclusion CNTG prevents hyperlipidemia via activation of hepatic LKB1-AMPK pathway.