参芪瓜蒌薤白半夏汤对动脉粥样硬化模型小鼠PPARγ、胆汁酸及血脂的影响

Effects of Shenqi Gualou Xiebai Banxia Decoction(参芪瓜蒌薤白半夏汤)on PPARγ,Bile Acids,and Blood Lipids in Mouse Models of Atherosclerosis

目的探究参芪瓜蒌薤白半夏汤(简称半夏方)治疗动脉粥样硬化的作用机制。方法将30只载脂蛋白E基因敲除(ApoE-/-)小鼠随机分为模型组、瑞舒伐他汀组及半夏方低、中、高剂量组,每组6只,给予高脂饲料喂养12周制备动脉粥样硬化模型。另设6只C57BL/6J野生型小鼠作为空白组。造模后半夏方低、中、高剂量组分别按照半夏方6.46、12.92、25.84 g/(kg·d)灌胃,瑞舒伐他汀组予瑞舒伐他汀片1.55 mg/(kg·d)灌胃,空白组和模型组给予生理盐水0.5 ml灌胃。4周后检测各组小鼠血清总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C),肝脏TC、TG水平;酶循环比色法检测血清胆汁酸水平;Real time RT-PCR法及Western blot法检测肝脏中过氧化物酶体增殖物激活受体γ(PPARγ)、固醇调节元件-结合蛋白2(SREBP2)、羟甲基戊二酸单酰辅酶A还原酶(HMGCR)、胆固醇7α-羟化酶(CYP7A1)的mRNA及蛋白表达。结果与空白组比较,模型组小鼠血清TG、TC、LDL-C水平均显著升高,HDL-C、胆汁酸水平显著下降,肝脏TG、TC水平显著升高,肝脏SREBP2、HMGCR蛋白及mRNA表达显著升高,PPARγ、CYP7A1蛋白及mRNA表达显著降低(均P<0.01)。与模型组比较,瑞舒伐他汀组及半夏方高剂量组血清TG、TC、LDL-C水平及肝脏TG、TC水平降低,胆汁酸水平升高,PPARγ、CYP7A1蛋白及mRNA表达升高,SREBP2、HMGCR蛋白及mRNA表达降低,半夏方低剂量组的血清TC、LDL-C水平和肝脏TC水平降低(P<0.05或P<0.01)。与瑞舒伐他汀组相比,半夏方低剂量组肝脏TC水平升高,半夏方高剂量组肝脏TC水平、CYP7A1 mRNA表达、PPARγ蛋白表达降低、SREBP2蛋白表达升高(P<0.05或P<0.01)。与半夏方低、中剂量组相比,半夏方高剂量组血清TG、肝脏TC水平降低(P<0.05)。结论半夏方可能通过调控PPARγ蛋白水平,同时影响肝脏胆固醇的生成和胆固醇向胆汁酸的转化,从而改善血脂水平,发挥抗动脉粥样硬化作用。

Objective To explore the mechanism of Shenqi Gualou Xiebai Banxia Decoction(参芪瓜蒌薤白半夏汤,SGXBD)in the treatment of atherosclerosis.Methods Thirty Apolipoprotein E gene knockout(ApoE-/-)mice were randomly divided into five groups:model group,rosuvastatin group,low-,moderate-,and high-dose SGXBD,with six mice in each group.They were fed a high-fat diet to prepare for atherosclerosis model.Another six C57BL/6J wild-type mice were set as the blank group.After modeling,the low-,moderate-,and high-dose SGXBD groups were gavaged with 6.46,12.92,and 25.84 g/(kg·d)of SGXBD,respectively.The rosuvastatin group was given 1.55 mg/(kg·d)of rosuvastatin tablets by gavage.The blank group and model group were given 0.5 ml saline by gavage.After four weeks,the total cholesterol(TC),triglyceride(TG),low-density lipoprotein cholesterol(LDL-C),and high-density lipoprotein cholesterol(HDL-C)in the serum of each group were detected,as well as TC and TG in the liver.The serum bile acid level was detected by enzyme cycling colorimetry.The mRNA and protein expression of peroxisome proliferator-activated receptorγ(PPARγ),sterol regulatory element-binding protein 2(SREBP2),3-hydroxy-3-methylglutaryl-CoA reductase(HMGCR),and cholesterol 7α-hydroxylase(CYP7A1)in the liver were detected by real-time RT-PCR and Western blot.Results Compared with the blank group,the model group showed significant increases in serum TG,TC,and LDL-C levels,and significant decreases in HDL-C and bile acid levels;the levels of TG and TC in the liver,as well as the expression of SREBP2 and HMGCR proteins and mRNA in the liver significantly increased,while the expression of PPARγand CYP7A1 proteins and mRNA significantly decreased(all P<0.01).Compared with the model group,the rosuvastatin group and high-dose SGXBD group showed significant decreases in serum TG,TC,and LDL-C levels and liver TG and TC levels,and significant increases in bile acid levels;the expression of PPARγand CYP7A1 proteins and mRNA increased,while the expression of SREBP2 and HMGCR proteins and mRNA decreased;the low-dose SGXBD group showed significant decreases in serum TC and LDL-C levels and liver TC level(P<0.05 or P<0.01).Compared with the rosuvastatin group,the low-dose SGXBD group had a significantly higher liver TC level,while the high-dose SGXBD group had a significantly lower liver TC level,CYP7A1 mRNA level,and PPARγprotein expression level,and a significantly higher SREBP2 protein expression level(P<0.05 or P<0.01).Compared with the low-and moderate-dose groups,the high-dose SGXBD group had significantly lower serum TG and liver TC levels(P<0.05).Conclusion SGXBD may improve blood lipid levels and exhibit anti-atherosclerotic effects by regulating the protein level of PPARγand simultaneously affecting the synthesis of liver cholesterol and the conversion of cholesterol to bile acids.