Background: Hypothermic ischemia-reperfusion arrhythmia remains the main factor affecting cardiac resuscitation under cardiopulmonary bypass. Existing research shows that certain miRNAs exhibit significantly different expressions and effects in arrhythmias, however, the effect of miRNAs on the progression of hypothermic ischemic-reperfusion arrhythmias (RA) and its potential mechanism remain to be further explored.
Methods: Sprague-Dawley (SD) rats were randomly divided into two groups (n = 8): a normal control group (Group C) and a hypothermic ischemia-reperfusion group (Group IR), which were used to establish a Langendorff isolated cardiac perfusion model. According to the arrhythmia scoring system, rats in group IR were divided into a high-risk group (IR-H) and a low-risk group (IR-L). miRNAs expression profiles of ventricular myocardium with global hypothermic ischemia-reperfusion and those of ventricular myocardium with hypothermic ischemia-RA were established through high-throughput sequencing. Furthermore, the aberrantly expressed miRNAs in myocardium with and without hypothermic ischemia-RA were screened and verified. The target genes of these aberrantly expressed miRNAs were predicted using RNAhybrid and MiRanda software. Based on Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, we determined the mRNA targets associated with these miRNAs and studied the miRNA-mRNA interaction during the cardiovascular disease progression. The aberrantly expressed miRNAs related to hypothermic ischemia-RA were validated by Real-time Quantitative polymerase chain reaction (RT-qPCR).
Results: Eight significantly aberrantly expressed miRNAs (rno-miR-122-5p, rno-miR-429, novel_miR-1, novel_miR-16, novel_miR-17, novel_miR-19, novel_miR-30, and novel_miR-43) were identified, among which six were up-regulated and two were down-regulated. Moreover, target genes and signaling pathways associated with these aberrantly expressed miRNAs were predicted and analyzed. The miRNA-mRNA interaction network graph showed that GJA1 gene was considered as the target of novel_miR-17.
Conclusions: Aberrantly expressed miRNAs were possibly associated with the formation mechanism of hypothermic ischemia-RA. Specific miRNAs, such as novel_miR-17 and rno-miR-429 are probably new potential targets for further functional studies of hypothermic ischemia-RA.
Keywords: Bioinformatics; Reperfusion arrhythmias; mRNA; microRNAs.