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目的探讨大气PM2.5对人肝肿瘤细胞株Hep G2细胞脂质堆积的影响及可能的作用机制。方法采集广州城区大气PM2.5,以6.25、12.5、25、50和100μg/ml PM2.5分别染毒Hep G2细胞,采用细胞活性检测试剂盒(CCK-8法)测定细胞存活率,确定PM2.5实验浓度。6.25、12.5、25μg/ml PM2.5染毒细胞36 h后,采用油红O染色观察肝细胞内脂滴变化,测定细胞内甘油三酯和总胆固醇含量,并采用实时荧光定量PCR法检测细胞肝X受体α(liver X receptor alpha,LXRα)和固醇调节元件结合蛋白-1c(sterol regulatory element binding protein-1c,SREBP-1c)的表达情况。结果油红O染色显示,染毒组Hep G2细胞内可见大量红色脂滴,并伴有脂滴融合现象。PM2.5染毒细胞36 h后,各染毒组Hep G2细胞总胆固醇含量高于对照组,但差异无统计学意义(P>0.05);甘油三酯含量高于对照组,且随着PM2.5浓度的增加而升高,差异均有统计学意义(P<0.05或P<0.01)。PM2.5染毒细胞24 h和36 h后,染毒组Hep G2细胞LXRα和SREBP-1c的m RNA表达均高于对照组,差异均有统计学意义(P<0.05或P<0.01)。结论 PM2.5可促进肝细胞脂质堆积,该过程可能与其上调LXRα和SREBP-1c的表达有关。
Objective To investigate the effects of atmospheric PM2.5 on lipid accumulation in human hepatocellular carcinoma cell line Hep G2 and its possible mechanism. Methods PM2.5 in Guangzhou urban area was collected and Hep G2 cells were exposed to 6.25, 12.5, 25, 50 and 100μg / ml PM2.5 respectively. Cell viability was measured by CCK-8 assay and PM2 .5 experimental concentration. After exposure to 6.25, 12.5 and 25μg / ml PM2.5 for 36 h, the changes of lipid droplets in hepatocytes were observed by oil red O staining. The levels of triglyceride and total cholesterol in cells were determined. The cells were detected by real-time fluorescence quantitative PCR The expression of liver X receptor alpha (LXRα) and sterol regulatory element binding protein-1c (SREBP-1c) were detected. Results Oil red O staining showed that a large number of red lipid droplets were observed in Hep G2 cells in the infected group, accompanied by lipid droplet fusion. After exposure to PM2.5 for 36 h, the total cholesterol content of Hep G2 cells in each exposure group was higher than that of the control group, but the difference was not statistically significant (P> 0.05). The triglyceride content was higher than that of the control group .5 concentration increased and increased, the difference was statistically significant (P <0.05 or P <0.01). The mRNA expression of LXRα and SREBP-1c in Hep G2 cells exposed to PM2.5 for 24 h and 36 h were significantly higher than that of the control group (P <0.05 or P <0.01). Conclusion PM2.5 can promote lipid accumulation in hepatocytes, which may be related to its up-regulation of LXRα and SREBP-1c expression.