他莫昔芬体外促进HepG2细胞脂肪变性观察

目的：研究他莫昔芬（TAM）对体外培养的HepG2细胞脂肪变性以及脂类代谢调控关键因子表达的影响。方法应用油酸（50μmol/L）处理HepG2细胞，诱导细胞脂肪变性体外模型，同时给予不同浓度的TAM （5～20μmol/L）干预72 h；采用油红O染色和甘油三酯含量测定检测HepG2细胞内脂质聚集情况；应用蛋白印迹法检测固醇调节元件结合蛋白-1c（SREBP-1c）、脂肪酸合成酶（FAS）、硬脂酰辅酶A去饱和酶（SCD）、肉酯软脂酰基转移酶（CPT1）和微粒体甘油三酯转移蛋白（MTP）的表达；采用细胞活性检测试剂盒测定细胞活性。结果在干预72 h后，模型组细胞内甘油三酯含量为（16.53＆#177;0.17） mg/100 mg蛋白质，在5μmol/L TAM处理细胞内甘油三酯含量为（17.77＆#177;0.05） mg/100mg蛋白质，与模型组无显著性差异，但在10μmol/L和20μmol/L TAM处理组较模型组分别增加了31%（21.57＆#177;0.16） mg/100 mg蛋白质]和44%（23.82＆#177;0.44） mg/100 mg蛋白质]，（P＆lt;0.05）；TAM上调细胞内SREBP-1c、FAS、SCD和MTP蛋白表达，但并不改变CPT1蛋白表达；TAM在5～20μmol/L范围内不影响HepG2细胞活性。结论 TAM可促进油酸诱导的HepG2细胞脂肪变性，其主要机制可能是通过上调SREBP-1c及其下游基因，如FAS和SCD的表达而增加了脂肪酸的合成。

Tamoxifen promotes lipid accumulation in HepG2 cells in vitro

Objective To investigate the effect of tamoxifen（TAM） on steatosis in HepG2 cells in vitro and on the expression of key regulators involved in lipid metabolism in the cells. Methods A cell model of steatosis was induced in HepG2 cells in vitro with oleic acid （OA） at 50 μmol/L;HepG2 cells were then subjected to dif-ferent concentrations of TAM （5 to 20 μmol/L） at the presence of OA for 72 h;Intracellular lipid accumulation was assessed by oil red O staining and measurement of triglyceride;The expression of sterol regulatory element-binding protein-1c（SREBP-1c）,fatty acid synthase（FAS）,steroyl-CoA desaturase（SCD）,carnitine palmitoyltrans-ferase 1（CPT1）and mitochondrial trifunctional protein（MTP）was determined by Western blot;Cell viability was de-tected by cell counting Kit-8 assay. Results After incubation for 72 h,the intracellular triglyceride in control group was （16.53±0.17） mg/100 mg protein,similar to that of cells treated with 5μmol/L TAM,however,the intra-cellular triglyceride was increased by 31%（21.57±0.16） mg/100 mg protein] and 44%（23.82±0.44） mg/100 mg protein] in cells treated with 10 μmol/L and 20 μmol/L of TAM,respectively（P〈±0.05）;TAM treatment（5 to 10 μmol/L） significantly increased the expression of SREBP-1c,FAS,SCD and MTP without affecting the expression of carni-tine palmitoyltransferase 1 （CPT1） in HepG2 cells;TAM did not affect HepG2 viability. Conclusions TAM pro-motes OA-induced cell steatosis,probably by up-regulation of SREBP-1c,FAS and SCD,thus increases fatty acid synthesis in the cells.