Protective effect of glycyrrhizin on inflammatory reactions in myocardial I/R injury rats. Protective effect of glycyrrhizin on plasma (A) NF-κB-p65, (B) TNF-α, (C) IL-1β and (D) IL-6 levels in rats with myocardial I/R injury. Data are presented as the mean ± standard deviation. **P<0.01 vs. Sham; ##P<0.01 vs. NS. I/R, ischemia/reperfusion; NF-κB-p65, nuclear factor kappa-light-chain-enhancer of activated B cells-p65; TNF-α, tumor necrosis factor-α; IL-1β, interleukin-1β; IL-6, interleukin-6; 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.