阿托伐他汀抑制Perilipin5表达降低肝脏脂质储积的病理学分析

Atorvastatin decreases liver lipid accumulation via inhibiting the expression of Perilipin 5: a pathological study

目的探讨阿托伐他汀(atorvastatin,ATR)对肝脏脂质代谢的影响及脂滴蛋白Perilipin5(Plin5)在其中的关键机制。方法采用高脂喂养野生型和Plin5敲除小鼠,利用生理盐水和每天ATR 20 mg/kg灌胃小鼠10天。取小鼠肝脏组织HE染色和油红O染色观察肝脏组织结构和脂质变化,并进行脂质定量分析。实时定量PCR和Western blot法检测肝脏组织脂滴相关蛋白表达水平。分离培养野生型小鼠原代肝细胞,使用Plin5过表达的腺病毒进行感染,Bodipy 493/503染色观察脂滴形态和数量,定量试剂盒测定原代肝细胞各脂质含量,Western blot分析脂质合成相关蛋白的表达水平。结果高脂喂养小鼠肝脏脂质储积明显增加,且ATR可以显著降低肝脏脂滴数量和大小,下调肝脏甘油三酯含量和胆固醇含量。同时,ATR能够下调脂滴蛋白Plin5的mRNA和蛋白水平。但是,ATR对Plin5缺失小鼠肝脏的脂肪含量无明显影响。原代肝细胞中过表达Plin5可显著增加肝细胞中脂滴数量和大小,提高肝细胞中甘油三酯含量。Plin5过表达增加乙酰辅酶A羧化酶(acetyl-Co A carboxylase 1,ACC1)和脂肪酸合成酶(fatty acid synthetase,FAS)等脂质合成相关酶的表达。结论 ATR能够降低肝细胞Plin5表达,抑制脂质合成,减少肝脏脂质储积。

Purpose To explicit the influence of atorvastatin treatment upon lipid metabolism in liver and to figure out the specific molecular roles of Perilipin 5（Plin5）,a LD-binding protein,in the lipid-lowering effects of atorvastatin. Methods The wild-type and Plin5 knockout mice fed with high-fat diet（HFD） were administrated with saline and 20 mg/kg/day atorvastatin（ATR） by gavage for 10 days,and then the alterations of hepatic morphology and lipid contents in liver were examined by hematoxylin-eosin（HE） and oil red O staining,and the triglyceride（TG） and cholesterol were quantitatively analyzed. LD associated proteins were determined by real-time quantitative PCR and Western blotting. The primary hepatocytes from wild-type mice were isolated and cultured,Plin5 was overexpressed by adenovirus infection,and the LDs were stained by Bodipy 493/503 and the total lipids quantified by commercial kits. Results The results indicated that HFD-treated mice showed the hepatic steatosis,and atorvastatin significantly decreased the amounts and sizes of LDs,and reduced TG and cholesterol contents in liver. Simultaneously,atorvastatin down-regulated the protein and mRNA levels of Plin5,but did not change the TG contents in Plin5 knockout mice. Moreover,the overexpression of Plin5 in primary hepatocytes increased the amounts and sizes of LDs,as well as the TG contents,by stimulating the enzymes involved in lipid biosynthesis, including acetyl-Co A carboxylase 1（ACC1） and fatty acid synthetase（FAS）. Conclusion Atorvastatin can reduce the expression of Plin5 in liver cells,and suppresses lipid biosynthesis,and reduces liver TG content.