MicroRNAs and Their Predicted TargetMessenger RNAs are Deregulated by Exposure to a Carcinogenic Dose of Comfrey in Rat Liver. Rattus norvegicus

MicroRNAs (miRNAs) are small non-coding RNAs that function as regulators of gene expression to control cell growth and differentiation. MiRNA levels are substantially altered in various types of tumors and have been used as biomarkers in defining malignant status. However, studies on responses of miRNA expression to carcinogen insults in their target tissues are rare. In this study, we analyzed miRNA expression in the livers of rats treated with carcinogenic dose of comfrey (Symphytum officinale), a rat botanical carcinogen. Overall design: Groups of 6 Big Blue Fisher 344 rats were fed a normal diet or a diet containing 8% comfrey root for 12 weeks. The animals were sacrificed one day after the last treatment and the livers were isolated from the control and treated rats for miRNA expression analysis. The miRNA expressions were determined using miRNA microarrays for human, mouse and rat (LC Sciences). Data were normalized using cyclic method and statistically analyzed using Ttest.

微小RNA（MicroRNAs，miRNAs）是一类小型非编码RNA，可作为基因表达调控因子，参与细胞生长与分化的调控过程。多种肿瘤组织中的miRNA水平会发生显著改变，因此miRNA可作为判定恶性肿瘤状态的生物标志物。然而，目前针对靶组织中miRNA表达对致癌物暴露的应答反应的研究仍较为匮乏。本研究针对经致癌剂量的聚合草（Symphytum officinale，一种大鼠源植物性致癌物）处理的大鼠肝脏组织中的miRNA表达水平进行了分析。
实验设计：将6只一组的Big Blue转基因Fisher 344大鼠分为两组，分别饲喂正常饲料与添加8%聚合草根的饲料，持续干预12周。末次处理后次日处死所有实验动物，分别从对照组与处理组大鼠体内分离肝脏组织，用于miRNA表达分析。本研究采用LC Sciences公司提供的人、小鼠及大鼠通用miRNA微阵列芯片进行miRNA表达水平检测。数据采用循环法进行归一化处理，并通过t检验完成统计学分析。