Detection of microRNAs and their target genes in heart of streptozotocin-induced diabetic mice

Objective To investigate the expression of microRNAs(miRNAs)in myocardial tissues of diabetic mice and to find the potential target genes controled by the miRNAs.Methods C57BL/6 mice were randomly divided into normal control and diabetes model group.The mice in diabetes model group were injected in peritoneal cavity with streptozocin(150 mg/kg).At the end of six weeks,the body weight and content of blood sugar were detected.The morphology of the heart tissue was detected using hematoxylin-eosin staining.The miRNA expressions in myocardial tissue of the mice were determined by using reverse transcription miRNA PCR array.The targets of the altered miRNAs were predicted using the database(Target Scan,miRarnada and PicTar). Then the target genes(Anp,Myh7,Hadc1,Col1a1,Ccnd1,and Vcam1)related to cardiac hypertrophy or myocardial fibrosis were analyzed with quantitative real-time PCR(qRT-PCR).Results Histological analysis of heart tissues exhibited cardiac hypertrophy and extensive interstitial fibrosis and the heart weight/body weight(HW/BW)ratio was significantly higher in diabetic group. Up-regulated miR-19a,miR-19b,miR-22,and miR-503 and down-regulated miR-1,miR-29a,miR-30a,miR-96,miR-101a,miR-142-3p,miR-199-5p,and miR-374 miRNAs were identified in diabetic mice with cardiomyopathy. Target genes were approved with bioinformatics analysis. Among the targets,the mRNA expressions of Anp,Myh7 and Ccnd1 were increased,while Hadc1,COL1A1 and Vcam1 were decreased in diabetic mice with cardiomyopathy.Conclusion The results demonstrate that miRNAs play an important role in the process of diabetic cardiomyopathy,which may mediate cardiac hypertrophy and/or myocardial fibrosis in diabetic cardiomyopathy.