| ObjectiveTo study the myocardial protection and mechanism of taurine in vivo.MethodsHealthy male wistar rats were randomly divided into five groups:(1) the sham group:threading under the left anterior descending branch (LAD) of coronary artery, putting aside.(2) the control group:oral saline10mL/kg, once daily for7days, and implementing30min ischemia/120min reperfusion on LAD.(3) the taurine low dosage group:oral taurine200mg/kg, once daily, for7days, and implementing30min ischemia/120min reperfusion on LAD.(4) the taurine middle dosage group: oral taurine400mg/kg, once daily, for7days, and implementing30min ischemia/120min reperfusion on LAD.(5) the taurine high dosage group:oral taurine800mg/kg, once daily, for7days, and implementing30min ischemia/120min reperfusion on LAD. Monitoring the Ⅱ lead ECG continuously, observeing the blood pressure,the heart rate,the onset time and duration of arrhythmias and the area of myocardial infarction after myocardial ischemia-reperfusion in rats; Serum vascular endothelial growth factor (VEGF), hypoxia-inducible factor-α (HIF-α), platelet-endothelial cell adhesion molecule (CD34) and myocardial tissue VEGF content was determined respectively. The Western blotting method was used to detect the expression of protein AKT, p-AKT and VEGF. Also the effects of taurine on the migration capacity of induced endothelial cell was measured by using the wWound-healing experiments and invasion experiment.Results1.The effects of taurine on cardiac physiology after I/R injury in ratsDuring the ischemia period, the onset time of VPc in ischemia-reperfusion model group (I/R) was (5.8±2.9) min and the duration was (13.3±5.6) min. Compared with the IR group, the onset time of VPc in the taurine low dosage group, middle dosage group and high dosage group was delayed by65.4%,71.9%and93.7%, respectively (P<0.01), meanwhile the durations reduced by34.8%、49.5%、55.6% respectively (P<0.01). In addition, there was no significant difference among the taurine-treated groups.. The incidence of VT and VF in the IR group were65.7%and42.3%respectively. Compared with the IR group, the incidence of VT and VF in the each of taurine-treated group decreased significantly (P<0.05), and there was no significant difference among the taurine-treated groups. During the period of reperfusion, VPC happened in the IR group, however, the frequency of occurrence was obviously less than ischemia period and VPC happened in the different dosage group of taurine occasionally. In addition, VT only happened in the IR group occasionally and there was no occurrence in taurine-treated groups, so we did not do statistics with ventricular arrhythmia during reperfusion.2. The effects of taurine on the morphology and size of the myocardial infarction of rats after I/R injuryThere was no significant difference in four groups about AAR. However, compared with the IR group, the ratio of IS to AAR decreased significantly in different dosage taurine groups. Observed under the light microscope, muscle fiber was complete and rrgular. There were no renascent capillaries in the mesenchyme of the IR group. New capillaries were not seen in the mesenchyme of the taurine low dosage group; little renascent capillaries were visible in the mesenchyme of the taurine middle dosage group; and more renascent capillaries were visible in the mesenchyme of the taurine high dosage group.3. The effects of taurine on serum enzymology of rats after I/R injuryCompared with the IR group, serum VEGF levels increased significantly in the each of taurine-treated group (P<0.01), and the effect is dosage-dependent manner.Compared with the IR group, serum HIF-a levels increased significantly in the each of taurine-treated group (P<0.01), and the effect is dosage-dependent manner.Compared with the IR group, serum CD34levels increased significantly in the each of taurine-treated group (P<0.01), and the effect is dosage-dependent manner.Compared with the IR group, myocardium VEGF levels increased significantly in the each of taurine-treated group (P<0.01), and the effect is dosage-dependent manner.4. The effects of taurine on the expression of protein AKT, p-AKT and VEGF in rats after myocardial ischemia/reperfusion injuryCompared with the sham group, the expression of AKT, p-AKT and VEGF increased significantly (P<0.01) in the IR group. Compared with the IR group, taurine significantly increased VEGF,AKT and p-AKT expression (P<0.01) with dosage-dependent manner. VEGF, AKT and p-AKT expression in the only taurine high-dose group were increased (P<0.01)。5. The migration effect of taurine on cultivating endothelial cells in vitroThe results of wound-healing experiment showed that about the endothelial cells increased by different concentration of taurine, the migration area of cells in medicine treatment groups to the center of scratch were significantly increased (P<0.01) compared with the control group, and the migration area of cells gradually increased with the increase of taurine concentration. The results of invasion experiment showed that the numbers of transmembrane cells in taurine groups were higher than which in the control group (P<0.01) after the medicine treatment; and the numbers of transmembrane cells gradually increased with the increase of taurine concentration.ConclusionIn vivo myocardial ischemia-reperfusion injury, Taurine treatment can significantly influence the heart physiology, reduce the myocardial infarct area induced by I/R injury, and improve the morphological changes of damaged myocardial cell. Meanwhile, Taurine treatment can stimulate the generation of VEGF factors, facilitate the expression of HIF-a, and increase the content of Serum CD34to promote angiogenesis and reduce the rate of myocardial ischemic necrosis. Moreover, they can enhance the expression of VEGF、AKT、p-AKT. The mechanism of protective action for taurine may be involved in the myocardium angiogenesis. |
PDF Full Text Request