Altered Expression of microRNAs in Serum Extracellular Vesicles in Rats with Severe Burns during Shock Stage

Background: The shock stage of severe burns is a critical determinant of prognosis and the induction of systemic inflammatory response syndrome and multiple organ failure. Extracellular vesicles (EVs) containing abundant miRNAs are known to participate in various biological processes. Due to the lack of research on alternations of miRNAs in severe burns, our study analyzed the miRNA profiles of EVs in severe burns during the shock stage. Methods: EVs were extracted from the serum of rats with severe burns (30% of total body surface area, III°), and the expression of miRNAs in serum EVs was determined by next-generation sequencing. Functional analysis of target genes of miRNAs that were significantly differentially expressed (DE) was performed using GO Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Results: Thirty-four DE miRNAs were identified at the early stage of severe burn shock and 63 at the late stage of severe burn shock. In addition, miRNA-339-5p, miRNA-1, miRNA-382-5p, miRNA134-5p, miRNA-133a-5p, and miRNA-365a-5p were DE throughout the entire shock stage, based on P < 0.01 and |log2 (foldchange)| ≥ 1 criteria. GO and KEGG analysis revealed that the target genes of DE miRNAs mainly enriched the metabolic process, immune system processes, and signal pathways. Conclusion: To our best knowledge, this is the first study demonstrating the miRNA expression profiles of EVs isolated from serum with severe burns during the shock stage. There are significant differences between downregulation and upregulation. Thus, miRNAs have the potential for novel biomarkers for the complication of severe burns.