Expression of microRNA-221 and its related mechanisms in rats with acute myocardial infarction

Abstract

Objective To explore expression of microRNA (miRNA, miR)-221 and its related mechanisms in rats with acute myocardial infarction (AMI). Methods AMI model was established by ligation of left anterior descending branch of coronary artery. Thirty-six AMI rats successfully established were randomly divided into AMI group, control group and inhibition group with 12 rats in each group. The control group and inhibition group was injected with green fluorescent protein (GFP) lentiviral vector miR-221 negative control (NC) and miR-221 inhibitor by local injection of myocardial tissue transfection, respectively. AMI group and sham operation group were given normal saline. The expression of miR-221, Apoptosis index (AI) in myocardium, The activity of aspartic proteinase (Caspase)-3 and Caspase-9, the expression of B lymphocytes -2 (bcl-2), bcl-2 associated X protein (bax), cyclin dependent protein kinase phosphatase signaling pathway activation was detected. Results Compared with AMI group and control group, AI (t=5.874, P<0.01), the activity of Caspase-3 (t=6.219, P<0.01), Caspase-9 (t=5.942, P<0.01) and the expression of bax (t=8.512, P<0.01), p27 (t=5.878, P<0.01), p57 (t=11.244, P<0.01), phosphatase and tensin homolog deleted on chromosome ten (PTEN, t=6.063, P<0.01) was decreased, the expression of bcl-2 (t=5.971, P<0.01) and p-Akt (t=9.140, P<0.01) was increased in inhibition group (P<0.01). Conclusion Down-expression of miR-221 could significantly inhibit AMI rat’ myocardial injury, which related to regulation of PTEN/Akt signal pathway. Key words: MicroRNA-221; Acute myocardial infarction; Rats; Myocardial injury