ABSTRACT
Objective To investigate the correlations between miRNA and mRNA ( the regulatory effects of miRNA) in a rat model of trinitro-benzene-sulfonic acid (TNBS)/ethanol induced ulcerative colitis ( UC) .Methods TNBS and ethanol were used to induce the development of UC in rats .After the modeling procedure and oral administration of normal saline ( NS) for 14 days, rats from the control and model groups were dissected to collect the samples of colonic mucosa .General and histological evaluations were performed to validate the modeling of UC .The expression of miRNA was profiled using miRNA microarray .The target miRNAs that were closely related to the pathogenesis of UC were selected out according to the results of mi -croarray and related literatures .RT-PCR was performed to verify the differentially expressed miRNAs .The mirWalk database was used to predict the target genes of miRNAs .In order to verify whether the predicted results were in accordance with the actual results , the microarray technology was used for mRNA expression profiling .The genes that showed interactions with those miRNAs were screened out .The David database was used for gene annotation .An interaction net between miRNA and mRNA was formed .Results General and histological manifestation of colon tissue samples from the model group were in accordance with the features of UC.Sixty-eight miRNAs were identified to be differentially expressed in rats from the model group and the control group (fold change>2, P7).Six candidate miRNAs were selected as hav-ing close relations to the pathogenesis of UC referring to reported literatures , the expression of which was checked and verified by real-time polymerase chain reaction (PCR).Compared with the control group, 4 miRNAs (miR-146a-5p, miR-146b-5p, miR-126a-3p and miR-21-5p) were up-regulated (P<0.01, P<0.05) and 2 miRNAs (miR-200b-3p and miR-145-5p) were down-regulated (P<0.01) in rats with TNBS/ethanol induced UC.Four mRNAs (IL-6, Ccl5, Mapk3 and Smad7) that interacted with the 6 miRNAs were identified based on the results of target gene prediction of the above 6 miRNAs and gene expression pro-filing.The David database was used to annotate the interactions for elucidating their significance in the path -ogenesis of UC .Conclusion A miRNA can regulate many signaling pathways and a signaling pathway can also be regulated by many miRNAs .Therefore , simply inhibiting certain pathways may not radically stop the process of inflammation .Studying the functions of miRNAs and elucidating the correlations between miRNA and mRNA might fundamentally inhibit the development of UC .