Abstract: OBJECTIVE: To investigate the efficacy of the Danlou Fang(DL) Traditional Chinese Medicine formula on microvascular obstruction(no-reflow) through the endothelial/inducible nitric oxide synthase(eNOS/iNOS) pathway in a rat model.METHODS: Sprague-Dawley rats were subjected to 60 min of coronary artery occlusion(or sham procedure) followed by 2 h of reperfusion and were then divided into treatment groups: sham, model, DL(500 mg/kg), DL(500 mg/kg) + eNOS inhibitor L-nitroarginine(L-NNA; 7.5 mg/kg), and sodium nitroprusside(SNP; 0.5 mg/kg). There were 16 per group. Areas of no-reflow were determined by thioflavin S staining of heart tissue. Cardiac function was assessed by echocardiography. Myocardial enzymes and antioxidants in serum were measured and analyzed. The relative protein expression levels of eNOS and iNOS were determined by western blotting.RESULTS: DL had a myocardial protective effect on myocardial reperfusion and reduced the area of no-reflow. The serum levels of creatine kinase(CK),myocardial CK isoenzyme CK-MB, and lactate dehydrogenase were significantly lower in the DL group than in the model(P < 0.05). DL treatment also decreased the serum content of malondialdehyde and reactive oxygen species(ROS), increased the activity of superoxide dismutase and nitric oxide,and promoted eNOS expression(P < 0.05) while lowering iNOS expression.CONCLUSION: DL reduced the area of no-reflow and had a myocardial protective effect that may be associated with the eNOS/iNOS pathway.

Key words: no-reflow phenomenon;;nitric oxide synthase;;creatine kinase;;nitroarginine;;reactive oxygen species;;Danlou Fang