Differential Expression of MicroRNAs in the Kidneys of Rats Following Sustained Swimming Exercise

Swimming exercise is reported to have protective effects on kidney function. Previous studies have indicated that microRNAs (miRNAs) are important for normal development, physiology, and pathophysiology of the kidney. Previous publications reported that swimming could modify miRNA expression profiles in the heart and brain. We studied the differential expression of miRNA in the kidneys of rats following sustained swimming exercise twice a day for 6 consecutive weeks. Small RNA libraries were made from the kidneys of sedentary control (SC) and sustained swimming exercised (SE) animals to identify the expression of miRNAs using high-throughput (deep) sequencing technology. We identified 521 and 516 known miRNAs and revealed 328 and 312 novel miRNA candidates with a total of 849 and 828 miRNAs in the kidneys of rats from the SC and SE libraries, respectively. Seventeen miRNAs were differentially expressed, of which 10 miRNAs were increased and 7 miRNAs were decreased in response to swimming exercise. The results showed that sustained swimming exercise could modulate renal miRNAs in rats. These differentially modified miRNA-s were investigated employing Gene Ontology (GO) terminologies and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. The results implied that these swimming-responsive miRNAs may interact with many types of target genes to regulate renal functions. Analysis of KEGG pathways found that the significantly enriched target genes of the modified miRNAs were involved in the thyroid signaling (ko04919) and Hippo signaling pathways (ko04390). Our study data suggest that sustained swimming exercise could induce deferential expression of renal miRNAs, which might modulate an adaptive response of the kidney.