不同浓度胆固醇对NEFA诱导的肝脂沉积的影响

Effects of different concentrations of cholesterol on NEFA-induced liver lipid deposition

旨在明确不同浓度胆固醇(CHO)对高非酯化脂肪酸(NEFA)所致的肝细胞脂质蓄积的影响特征。BRL-3A大鼠肝细胞添加1.2 mmol/L NEFA处理30 min后,再添加10、30、60、100、150μmol/L MβCD-CHO溶液刺激12 h,测定细胞总胆固醇(TC)、甘油三酯(TG)和培养液极低密度脂蛋白(VLDL)含量,同时检测细胞SREBP-1c、ACC1、SREBP-2c mRNA的表达水平和脂滴表达。结果显示,NEFA组细胞TC的含量低于对照组;NEFA+10μmol/L CHO组TC含量与对照组无显著差异,SREBP-1c、ACC1表达水平、TG和脂滴含量均显著低于NEFA组,SREBP-2c表达水平和VLDL含量显著高于NEFA组(P<0.05);而NEFA+150μmol/L CHO组细胞内TC、TG含量和脂滴生成量显著高于对照组和NEFA组,SREBP-1c、ACC1表达水平均极显著高于对照组和NEFA组(P<0.01),SREBP-2表达水平和VLDL含量极显著低于NEFA组(P<0.01)。结果表明,NEFA介导的肝脂蓄积过程中存在CHO合成代谢障碍,10μmol/L CHO添加能有效降低NEFA介导的肝脂蓄积,150μmol/L高胆固醇添加造成细胞受损和脂质毒性继而加重肝脂蓄积。

To clarify the effect of different concentrations of cholesterol(CHO) on the lipid accumulation of hepatocytes caused by high non-esterified fatty acids(NEFA). Rat hepatocytes(BRL-3 A) were treated with 1.2 mmol/L NEFA for 30 min, and then stimulated with 10, 30, 60, 100 and 150 μmol/L MβCD-CHO solution for 12 h. Total cell cholesterol(TC) and triglycerides(TG) and very low density lipoprotein(VLDL) content in the culture medium were measured, while the expression levels of SREBP-1 c, ACC1, SREBP-2 c mRNA and lipid droplet production in cells were detected. The results showed that the TC content of the NEFA group was lower than that of the control group. The TC content of the NEFA + 10 μmol/L CHO group was not significantly different from that of the control group,and the expression levels of SREBP-1 c,ACC1,TG and lipid droplets were significantly lower than those of the NEFA group.SREBP-2 cexpression level and VLDL content were significantly higher than those of the NEFA group(P<0.05);while the TC,TG content and lipid droplet production of the NEFA+150μmol/L CHO group were significantly higher than those of the control and NEFA groups.The expression level of ACC1 was significantly higher than that of the control and NEFA groups(P<0.01),and the expression level of SREBP-2 and the content of VLDL were significantly lower than those of the NEFA group(P<0.01).The results indicate that there is an obstacle to cholesterol anabolic metabolism during NEFA-mediated liver lipid accumulation.Addition of 10μmol/L cholesterol can effectively reduce NEFA-mediated liver lipid accumulation.Addition of 150μmol/L high cholesterol causes cell damage and lipid toxicity,which in turn increases liver fat accumulation.