Expression profiles and bioinformatic analysis of circRNAs in cardiac fibrosis of db/db mice

To identify the differential expression of circRNAs in cardiac fibrosis of db/db mice, db/db mice cardiac apex tissues were detected through microarray analysis at the age of 21 weeks. Compared with normal control mice, 77 circRNAs were up-regulated and 135 circRNAs were down-regulated in the chromosomes of db/db mice (fold changes ≥1.5, p-values ≤ 0.05). Moreover, Real-time qPCR was performed to validate the expression of circRNAs. In db/db mice, the top four up-regulated circRNAs, mmu_circRNA_28667, mmu_circRNA_32303, mmu_circRNA_20674, mmu_circRNA_25425 were verified. In db/db mice, the top four down-regulated circRNAs which were indexed by circBase database were verified. They were mmu_circRNA_014302, mmu_circRNA_001535, mmu_circRNA_005522 and mmu_circRNA_013422. Cardiac tissue samples were collected from db/db (n = 3) and C57BL/6 (n = 3) mice at age of 21 weeks. Three independent experiments were performed at the age of 21 weeks using different donors for each experiment.