Protective effect of glycyrrhizin on iNOS in myocardial I/R injury rats. To investigate whether the role of the protective effect of glycyrrhizin towards myocardial I/R injury occurs via iNOS production, iNOS miRNA expression levels in rats with myocardial I/R injury were determined. Data are presented as the mean ± standard deviation. **P<0.01 vs. Sham; ##P<0.01 vs. NS. I/R, ischemia/reperfusion; iNOS, inducible nitric oxide synthase; Sham, sham-treated group; NS, myocardial I/R injury + non-treated group; 2 mg/kg, myocardial I/R injury + pre-treatment with 2 mg/kg glycyrrhizin group; 4 mg/kg, myocardial I/R injury + pre-treatment with 4 mg/kg glycyrrhizin group; 10 mg/kg, myocardial I/R injury + pre-treatment with 10 mg/kg glycyrrhizin group.