Circular RNA ciRs-126 promotes hypoxia/reoxygenation cardiac injury possibly through miR-21

BACKGROUND: This study aimed to analyze the role of circular RNA ciRs-126 in hypoxia/reoxygenation cardiac injury (H/R). METHODS: Expression of ciRs-126 and miR-21 in plasma samples from patients with H/R and healthy controls was determined by RT-qPCR. Correlations were analyzed by linear regression. Overexpression of ciRs-126 and miR-21 was achieved in cardiomyocytes to explore their crosstalk. The roles of ciRs-126 and miR-21 in H/R-induced apoptosis of cardiomyocytes were analyzed using cell apoptosis assay. RESULTS: CiRs-126 was upregulated and miR-21 was downregulated in H/R patients. They were inversely correlated across plasma samples from H/R patients. In H/R cardiomyocytes, ciRs-126 was upregulated and miR-21 was downregulated. In cardiomyocytes, ciRs-126 overexpression decreased miR-21 level and reduced the inhibitory effects of miR-21 overexpression on H/R-induced cell apoptosis. CONCLUSIONS: Circular RNA ciRs-126 may suppress miR-21 expression to promote H/R cardiac injury. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12959-021-00355-x.