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目的:微小RNA(microRNAs,miRNAs)在胆固醇的合成,代谢和转运中起着重要作用,而mi RNAs在胆固醇代谢物胆酸的代谢和转运中的作用尚不清楚。Dicer基因是miRNAs生成过程的关键酶。本课题使用肝脏特异的Dicer1基因敲除小鼠,考察肝脏Dicer1基因敲除对C57BL/6小鼠肝脏胆酸代谢和转运的影响。方法:使用白蛋白启动子驱动的Cre重组酶和Loxp系统(Alb-Cre/Loxp)在小鼠肝脏中特异的敲除Dicer1基因;分别收集3~12周龄的小鼠血液和肝脏组织,使用Cobas生化仪检测小鼠血液和肝脏中总胆酸含量;利用实时定量PCR的方法分析肝脏中胆汁酸代谢转运相关基因的表达。结果:实验发现,肝脏Dicer基因敲除后,胆酸在血液和肝脏中明显蓄积,弥漫性肝细胞轻微空泡化,偶见单个肝细胞坏死。检测胆酸代谢和转运相关基因的表达发现,胆酸合成相关基因的表达有轻度升高,但缺乏统计学差异;在肝脏细胞血管侧的胆酸摄取转运体中,Oatp1a1在Dicer1敲除小鼠肝脏中明显下调,Ntcp和Oatp1b2则无明显改变;而肝细胞血管侧胆酸外排转运体的表达均有显著升高,胆管侧的外排转运体中Abcb11表达有明显增加。结论:Dicer基因敲除后,胆酸在血液和肝脏中明显蓄积,肝脏和血液中胆酸总量显著增加。血液中胆酸的蓄积可能与肝脏细胞血管侧摄取转运体的低表达和血管侧外排转运体的高表达有关;而肝脏中胆酸的蓄积可能部分来自于轻度升高的胆酸合成酶,胆酸在肝细胞内运输途径的紊乱可能与肝脏和血液中胆酸总量的显著增加相关。
AIM: MicroRNAs (miRNAs) play an important role in the synthesis, metabolism and transport of cholesterol, and the role of miRNAs in the metabolism and transport of cholesterol metabolites, bile acids, remains unclear. The Dicer gene is a key enzyme in miRNAs production. In this study, liver-specific Dicer1 knockout mice were used to investigate the effect of hepatic Dicer1 knockout on hepatic bile acid metabolism and transport in C57BL / 6 mice. Methods: The Dicer1 gene was specifically knocked out in mouse liver by Cre recombinase driven by albumin promoter and Loxp system (Alb-Cre / Loxp). The blood and liver tissues of mice aged 3 ~ 12 weeks were collected, Cobas biochemical analyzer was used to detect the content of total cholic acid in blood and liver of mice. The expression of bile acid metabolism and transport related genes in liver was analyzed by real-time quantitative PCR. Results: The experiment found that after Dicer gene knockout, the bile acids accumulated obviously in the blood and the liver, the diffuse hepatocytes were slightly vacuolized, and occasionally a single liver cell necrosis. Detection of bile acid metabolism and transport-related gene expression found that the expression of bile acid synthesis-related genes slightly increased, but the lack of statistical differences; in the hepatic vascular blood side of the bile acid uptake transporter, Oatp1a1 Dicer1 knockout small While the expression of Ntcp and Oatp1b2 did not change significantly. However, the expression of hepatic cholinergic efflux transporter was significantly increased, and Abcb11 expression was significantly increased in the ductal efflux transporter. CONCLUSION: After Dicer gene knockout, cholic acid accumulates significantly in blood and liver, and the total amount of cholic acid in liver and blood is significantly increased. The accumulation of cholic acid in the blood may be related to the low expression of the hepatic vascular compartment transporter and the high expression of the vasomotor efflux transporter whereas the accumulation of cholic acid in the liver may be partly due to the slightly elevated cholic acid synthase The disorder of cholic acid transport in hepatocytes may be associated with a significant increase in the total amount of cholic acid in the liver and blood.