Role of miRNA-214 in myocardial injury in septic mice

Objective To evaluate the role of miRNA-214 in myocardial injury in septic mice. Methods Sixty-six healthy male Kunming mice, weighing 25–30 g, were randomLy (random number) divided into 4 groups: sham operation group (Sham group, n=18) , cecal ligation and puncture group (CLP group, n=18) , CLP+ miRNA-214 precursor treated group (pre-miR-214 group, n=12) , CLP+ miRNA-214 inhibitor treated (anti-miR-214 group, n=12) , and the rest six mice were treated with miRNA-214 precursor or inhibitor intravenously. Sepsis was induced by CLP, pre-miR-214 group and anti-miR-214 group were respectively treated with miRNA-214 precursor or miRNA-214 inhibitor before the CLP, Sham group were exposed to the cecum only. Mice were sacrificed and hearts were removed for determination of miRNA-214 expression by RT-PCR in Sham and CLP group at 6 h, 12 h, and 24 h. Blood samples were collected from inferior vena cava at 12 h and 24 h after CLP for determination of the B-type natriuretic peptide (BNP) and cardiac troponin-I (cTnI) concentration by ELISA, then the mice were sacrificed and hearts were removed for determination of the inflammatory factor concentration by ELISA, cardiac myocyte apoptosis rate by flow cytometry and histopathological changes by microscopic examination. Statistical analysis was carried out with SPSS 13.0 software for One-way ANOVA. Results (1) The miRNA-214 expression was higher in CLP group than that in Sham group at 6 h, 12 h and 24 h; (2) Compared with CLP group, the miRNA-214 expression in pre-miR-214 group was increased, but decreased in anti-miR-214 group at 12 h; (3) Compared with CLP group, the concentrations of the serum BNP, cTNI, tumor necrosis factor-alpha (TNF-α) and the interleukin-6 (IL-6) were lower than those in pre-miR-214 group, whereas the interleukin-10 (IL-10) was increased. However, the levels of these variables changed just in opposite direction in anti-miR-214 group at 12 h, 24 h; (4) Compared with CLP group, the myocardial cell apoptosis rate was decreased in pre-miR-214 group, but increased in anti-miR-214 group at 24 h; (5) The microscopic examination showed that myocardial injury was attenuated in pre-miR-214 group compared with CLP group. Conclusions The miRNA-214 expression was increased in myocardial injury in CLP mice, suggesting miRNA-214 expression relating to myocardial protection in sepsis. Key words: MicroRNA; Sepsis; Myocardial injury; Inflammatory factor; Mycardial enzyme; Apoptosis