Analysis Of MicroRNAs Expression Pattern In Congestive Heart Failure Model Of Canine And The Impact Of Intravenous Heparin On MicroRNAs

Background and Aim: Congestive heart failure (CHF) is terminal state ofcardiovascular diseases. MicroRNAs (miRNAs) are21~25-nucleotide-long,endogenous, evolutionarily conserved, non-coding RNAs. Different expressions ofmiRNAs in tissues and blood have been described in various diseases, but thealterations of circulating miRNAs in heart failure were not studied. The purpose of thestudy was to eveluate expression of several miRNAs in left ventricular, and plasma in acanine model of heart failure induced by right ventricular tachypacing, and to assessthat if the levels of circulating miRNAs might reflect their levels in heart tissue.Methods: The pacing electrode was inserted in the canine’s apex of the right ventricle,and ventricular pacing at240~260bpm was maintained. According to the stimulationtime, twelve canines were divided into two groups: control group and ventriculartachypacing2-week-group. We collect plasma on1day,1week, and2weeks. At theend of2weeks, we measured the left ventricular end-diastolic pressure. Then, leftventricular tissues samples were obtained. The expressions of miRNA-21,miRNA-133a, miRNA-328, miRNA-423and miRNA-499in plasma, and leftventricular tissues samples were analyzed by real-time reverse-transcriptionpolymerase chain reaction.Results: In the left ventricular tissues, miR-499and miR-328were found to bedecreased significantly (P<0.05). In plasma, after rapid ventricular pacing for1day,miR-21、 miR-133a、 miR-423a、 miR-499were found to be increasedsignificantly(P<0.05). However,2weeks later, there are no significantly differencesbetween control group and ventricular tachypacing2-week-group in miR-423a andmiRNA-499. At the meanwhile after rapid ventricular pacing for1day, miR-328wasfound to be decreased significantly (P<0.05), and did not alternate with tachypacingtime.Conclusion: miR-328was downregulated in plasma and myocardial tissuessimultaneously, its circulating relative levels could show the relative levels inmyocardial tissues. MiR-21、 miR-133a、 miR-423a、 miR-499may become thebiomarkers. And miR-328may become to be the potential therapeutic targets of HF inthis model. Background and Aim: With the high development of interventional therapy, heparinhas become an increasingly popular durg in heart diseases. In this article, we aim tostudy the impact of intravenous heparin on the amplification efficiency of PCR onmicroRNAs in plasma and tissues.Methods: Nine dogs were randomly divided into control group(n=5) and intravenousheparin group(n=4). In the intravenous heparin group, we give1ml6000U heparin and2ml heparin-Nacl water intrathecal injiection.10mins later we collected venous blood10ml through the sheathing canal. Abandon the first10ml venous blood. Using newinjection syringe collect6ml venous blood to the EDTA-anticoagulant tube. Executeddogs by losing blood and then collected tissues of left ventricle in intravenous heparingroup, so as the control group expect injected heparin. Analyse microRNAs in plasmaand tissues by RT-qPCR.Results: Compared with control group, the intravenous heparin group Ct values ofmiRNA in plasma increased significantly（P＜0.01）.At the meanwhile there was nostatistically significance in tissues.Conclusion: Heparin has a significant influence on the amplification efficiency ofPCR on microRNAs in plasma and has no obvious effect on that in tissues.