Protective Effect Of TFR Pharmacological Preconditioning On Rat Myocardial Ischemia And Reperfusion Injury And Its Mechanism

Total flavones of Rhododendra(TFR) was extracted from the flower of Cuckoo. The essential components of TFR are quercetin, hyperin and other flavonoids. It has been preliminary assessed to be of protection against myocardial ischemia given via intragastric or ranine vein administration. The protective effect of TFR pharmacological preconditioning(TFR-PP) on myocardial ischemia and reperfusion injury and its mechanism were studied in this paper, the main results are following:1, On the model of myocardial ischemia and reperfusion in rat, all animals were subjected to 30 minutes occlusion of the left anterior descending coronary artery(LAD) and 60 minutes of reperfusion. TFR-PP animals received 3 cycles of 5 minutes intravenous perfusion of TFR 10, 20, 40 mg/kg interspersed with drug-free periods 24 hours before ischemia and reperfusion(I/R). 10, 20, 40 mg/kg TFR-PP could markedly inhibit the raise of S-T segment in ECG, the increase of serum CK and LDH activities and serum MDA contents, and the reductions of serum NO contents and serum NOS and SOD activities. TFR-PP(20, 40mg/kg) could markedly decrease IS/AAR, and TFR-PP(40 mg/kg) could significantly increase the expression of inducible nitricoxide synthase (iNOS) mRNA.2,The isolated perfused rat heart set up by Langendorff system was subject to 30 min ischemia followed by 40 min reperfusion, TFR-PP group hearts were subject to three cycles of 5 min perfusion of TFR periods interspersed with TFR-free periods. 12.5, 25, 50 and 100mg/L TFR-PP markedly inhibited the reduction of coronary flow, the increase of MDA content and the reductions of NO content and NOS activity in...