加味香砂六君子汤调控高脂血症小鼠apoA-Ⅰ改善内质网应激的作用机制研究

The mechanism of modified Xiangsha Liujunzi Decoction in regulating apoA-I and improving endoplasmic reticulum stress in hyperlipidemic mice

目的探讨加味香砂六君子汤调控小鼠载脂蛋白A-Ⅰ(apoA-Ⅰ)改善内质网应激调节糖脂代谢防治血脂异常的机制。方法将野生型C57BL/6J小鼠根据随机数字表法分为野生组、野生高脂组、野生中药干预组,将apoA-Ⅰ基因敲除小鼠根据随机数字表法分为敲除组、敲除高脂组、敲除中药干预组,每组10只。除野生组和敲除组正常饮食喂养外,各组小鼠采用D12492高脂饲料进行高脂饮食喂饲,建立高脂血症小鼠模型。于第9周开始野生中药干预组和敲除中药干预组小鼠每天给予加味香砂六君子汤(23.66 g/kg)灌胃给药,4周后,收集小鼠血清及肝脏组织用于后续检测。全自动生化分析仪检测血脂水平;ELISA法检测血清空腹血糖(FBG)及胰岛素(INS)水平,计算胰岛素抵抗(HOMA-IR)指数;HE染色观察肝脏病理变化;油红O染色观察肝脏脂质沉积情况;微板法检测肝脏组织甘油三酯(TG)水平;实时荧光PCR法检测肝脏组织apoA-Ⅰ、葡萄糖调节蛋白78(GRP78)、固醇调节元件结合蛋白-1c(SREBP-1c)、乙酰辅酶A羧化酶1(ACC1)、脂肪酸合酶(FASN)mRNA表达,WES全自动蛋白表达分析系统检测肝脏组织apoA-Ⅰ、GRP78、肌醇需求酶1(IRE1)、磷酸化IREI(p-IRE1)、c-Jun氨基末端激酶(JNK)、磷酸化JNK(p-JNK)、胰岛素受体底物1(IRS1)、磷酸化IRS1(p-IRS1)、蛋白激酶B(Akt)、p-Akt、SREBP-1c、ACC1、FASN蛋白表达。结果野生高脂组相较于野生组血清中血脂、FBG、INS水平及HOMA-IR指数升高(P<0.05);肝脏组织中橘红色脂滴增多,脂肪空泡明显,TG水平增加,apoA-ⅠmRNA及蛋白表达降低,GRP78、SREBP-1c、ACC1、FASN mRNA表达升高,GRP78、SREBP-1c、ACC1、FASN蛋白水平及IRE1、JNK、IRS1、Akt磷酸化程度升高(P<0.05)。野生中药干预组与野生高脂组比较,血清中TC、TG、HDL-C、LDL-C、FBG、INS水平及HOMA-IR指数降低(P<0.05);肝脏组织中橘红色脂滴明显减少,脂肪空泡化减轻,TG水平降低,apoA-ⅠmRNA及蛋白表达升高,GRP78、SREBP-1c、ACC1、FASN mRNA表达水平降低,GRP78、SREBP-1c、ACC1、FASN蛋白水平及IRE1、JNK、IRS1、Akt磷酸化程度降低(P<0.05)。敲除高脂组相较于野生高脂组,血清中TG、LDL-C、FBG水平及HOMA-IR指数升高,HDL-C水平降低(P<0.05);肝脏组织弥漫性橘红色脂滴,脂肪空泡明显增多,TG水平升高,GRP78、SREBP-1c、ACC1、FASN mRNA表达水平升高,SREBP-1c、ACC1蛋白水平及IRE1、JNK、IRS1、Akt磷酸化程度升高(P<0.05)。敲除中药干预组相较于野生中药干预组,血清中TG、LDL-C、FBG、INS水平及HOMA-IR指数升高,HDL-C水平降低(P<0.05);肝脏组织橘红色脂滴沉积情况改善,TG水平降低,GRP78、SREBP-1c、ACC1、FASN mRNA表达水平升高,GRP78、SREBP-1c、ACC1、FASN蛋白水平及IRE1、JNK、IRS1、Akt磷酸化程度升高(P<0.05)。结论加味香砂六君子汤通过调控apoA-Ⅰ缓解内质网应激,进而改善肝脏糖脂代谢紊乱。

Objective To explore the mechanism of modified Xiangsha Liujunzi Decoction in regulating apolipoproteinA-I(apoA-I),improving endoplasmic reticulum stress,regulating glucose and lipid metabolism,and preventing and treating dyslipidemia in mice.Methods Wild-type(WT)C57BL/6J mice were randomly divided into the WT,WT+high-fat diet(HFD),and WT+HFD+Xiangsha Liujunzi Decoction(XSLJZ)groups according to the random number table method.ApoA-Ⅰ-/-mice were randomly divided into the apoA-Ⅰ-/-,apoA-Ⅰ-/-+HFD,and apoA-Ⅰ-/-+HFD+XSLJZ groups(n=10)according to the random number table method.D12492 was used for HFD feeding to establish a hyperlipidemic mouse model.Modified XSLJZ(23.66 g/kg)was administered daily by gavage from the ninth week.Serum and liver tissue were collected for testing after 4 weeks.An automatic biochemical analyzer was used to detect blood lipid levels;an enzyme-linked immunosorbent assay was used to detect serum fasting blood glucose(FBG)and insulin(INS)levels,and the INS resistance index(HOMA-IR)was calculated.Hematoxylin and eosin staining was used to observe the pathological changes in the liver.Oil red O staining was used to observe the lipid deposition in the liver.TG levels in liver tissue were detected using the microplate method.Real-time PCR was used to detect apoA-Ⅰ,glucose-regulated proteins(GRP78),sterol regulatory element binding protein-1c(SREBP-1c),acetyl CoA carboxylase 1(ACC1),and fatty acid synthase(FASN)mRNA expression levels in liver tissue.The WES fully automated protein expression analysis system was used to detect apoA-Ⅰ,GRP78,inositol-requiring enzyme 1(IRE1),p-IRE1,c-Jun N-terminal kinase(JNK),p-JNK,insulin receptor substrate(IRS1),p-IRS1,protein kinase B(Akt),p-Akt,SREBP-1c,ACC1,and FASN protein expression levels in liver tissue.Results Compared to the WT group,the WT+HFD group showed a significant increase in serum lipids,FBG,INS levels,and the HOMA-IR index(P<0.05).The orange-red lipid droplets in liver tissue increased,fat vacuoles were apparent,and TG levels were significantly increased.ApoA-ⅠmRNA and protein expression levels were significantly reduced,whereas GRP78,SREBP-1c,ACC1,and FASN mRNA expression levels were increased,GRP78,SREBP-1c,ACC1,and FASN protein levels and the IRE1,JNK,IRS1,and Akt phosphorylation degree were increased(P<0.05).The serum TG,HDL-C,LDL-C,FBG,and INS levels and the HOMA-IR index in the WT+HFD group were significantly reduced after administering modified XSLJZ(P<0.05).The orange-red lipid droplets in liver tissue were significantly reduced,fat vacuolization was alleviated,and TG levels were significantly reduced,ApoA-ⅠmRNA and protein expression levels were significantly increased,whereas GRP78,SREBP-1c,ACC1,and FASN mRNA expression levels were reduced,GRP78,SREBP-1c,ACC1,and FASN protein expression levels and the IRE1,JNK,IRS1,and Akt phosphorylation degree were reduced(P<0.05).Compared to the WT+HFD group,the TG,LDL-C,and FBG levels and HOMA-IR index in the serum of the apoA-Ⅰ-/-+HFD group were significantly increased,whereas the HDL-C levels were significantly decreased(P<0.05).Diffuse orange-red lipid droplets in liver tissue and a significant increase in fat vacuoles were observed.Furthermore,TG levels were significantly increased,SREBP-1c,ACC1,FASN mRNA,SREBP-1c,and ACC1 protein expression levels and IRE1,JNK,IRS1,and Akt phosphorylation levels were significantly increased(P<0.05).Compared to the WT+HFD+XSLJZ group,the apoA-Ⅰ-/-+HFD+XSLJZ group showed a significant increase in serum TG,LDL-C,FBG,and INS levels,and the HOMA-IR index,whereas HDL-C levels decreased significantly(P<0.05).The deposition of orange-red lipid droplets in liver tissue improved,and TG levels significantly decreased,GRP78,SREBP-1c,ACC1,and FASN mRNA expression levels,GRP78,SREBP-1c,and ACC1 protein levels,and IRE1,JNK,IRS1,and Akt phosphorylation levels increased(P<0.05).Conclusion Modified XSLJZ improves liver glucose and lipid metabolism disorder by regulating apoA-Ⅰto alleviate endoplasmic reticulum stress.