氧化苦参碱对高果糖喂养诱导大鼠脂肪肝和肝脏内质网应激的干预作用

Effects of Oxymatrine on High-fructose-feeding-induced Fatty Liver and Endoplasmic Reticulum Stress in Rats

目的观察氧化苦参碱干预对高果糖饮食诱导大鼠肝脏脂质沉积的影响,并观察高果糖喂养对大鼠肝内内质网应激(ERS)的影响及氧化苦参碱的干预作用。方法雄性Wistar大鼠分为对照组、高果糖组和氧化苦参碱组,喂养16周后处死大鼠并测定各组大鼠空腹血糖(FBG)、空腹血胰岛素(FINS)水平,计算HOMA指数,测定血清谷丙转氨酶(ALT)、谷草转氨酶(AST)含量及肝脏TG含量,采用油红O染色观察肝脏组织的病理改变;测定ERS标志物内质网伴侣分子78(GRP78)、CHOPmRNA表达以及蛋白磷酸化胰腺内质网激酶(p-PERK)、磷酸化山梨醇要求激酶1(p-IRE1)和活化转录因子6(ATF-6)蛋白表达。结果与对照组比较,高果糖组的FBG、FINS、HOMA指数、血ALT、血AST及肝TG均显著增高(P均<0.01),同时肝组织油红O染色显示高果糖组大鼠肝细胞已有明显脂滴沉积;与高果糖组比较,氧化苦参碱干预组的上述指标均显著降低(P均<0.01),油红O染色显示肝组织内脂质沉积亦显著减轻;与对照组比较,高果糖组大鼠的肝内GRP78、CHOP表达显著增加,p-PERK、p-IRE1和ATF-6的蛋白表达亦显著增加(P均<0.01),而氧化苦参碱组上述ERS标志物的基因和蛋白表达均显著低于高果糖组(P均<0.01)。结论长期高果糖喂养引起大鼠胰岛素抵抗、肝脏脂质沉积及肝细胞损伤,并伴有肝细胞内ERS,氧化苦参碱治疗可改善高果糖饮食诱导的脂肪肝和肝细胞损伤,其机制可能与氧化苦参碱改善肝脏ERS有关。

Objective To observe the effects of oxymatrine intervention on high-fructose-feeding-induced liver steatosis in rats.To analyze the effects of high-fructose-feeding on endoplasmic reticulum（ER） stress in rats liver and the intervention effects of oxymatrine.Methods Male Wistar rats were randomly divided into control group,high fructose group and oxymatrine group（oxymatrine intervention was started after 4 weeks of high fructose feeding,40 mg/kg）.Rats were sacrificed after 16-weeks of high fructose feeding.Fasting blood glucose,fasting serum insulin were measured.HOMA index were calculated.Serum alanine aminotransferase（ALT）,serum aspartate aminotransferase（AST） and liver triglyceride content were determined.Gene expressions of GRP78 and CHOP in liver were detected.Protein levels of ER stress markers such as phosphorylated pancreatic ER kinase（p-PERK）,phophorylated inositol-requiring enzyme 1（p-IRE1） and activation transcription factor-6（ATF-6） in liver tissues were detected.Results Compared with control group,FBG,FINS,HOMA index,serum ALT,serum AST and triglyceride contents in liver tissues were significantly increased in high-fructose group（P 0.01）.Compared with high-fructose group,all above mentioned index were significantly lower in oxymatrine group（P 0.01）.The gene expression of GRP78 and CHOP and the protein expression of p-PERK,p-IRE1 and ATF-6 were significantly increased in high-fructose group compared with control group（P 0.01）.While in oxymatrine group,both gene markers and protein markers of ER stress in liver were decreased（P 0.01）.Conclusion Long-term high-fructose-feeding can induce liver steatosis and liver cell injury in rats,and accompanied by liver cell ER stress.Oxymatrine treatment can improve high-fructose-feeding-induced fatty liver and liver cell injury,in which the underlying mechanism might be associated with the alleviation of ER stress through oxymatrine intervention.