1,QDPTP Protects The Heart From Injury Induced By Ischemia/ Reperfusion In Isolated Rat Hearts: Effect And Mechanism Study 2,The Effects Of 3,5,4'-trihydroxy-trans-stilbene And 3,5,4'-trime-Thoxy-trans-stilbene On I_Na In Guinea Pig Vent

Part I QDPTP protects the heart from injury induced by ischemia/ reperfusion in isolated rat hearts: effect and mechanism studyQidan extractive (QDPTP) is a traditional Chinese drug according to traditional Chinese medicine theory. Astragali is the principal drug,danshen, chuanxiong and safflower are the ministerial drugs,ginkgo leaf, Panax pseudo-ginseng and integripetal rhodiola herb are the adjuvant and messenger drugs in the recipe. The purpose of this study is to investigate the protection effect of QDPTP on heart injuried by ischemia-reperfusion (I/R). We adopt isolated rat heart Langendorff nonrecirculating perfusion model, in order to exclude the interference of other neurohormones.1. The effect of QDPTP on left ventricular developed pressure(LVDP), coronary flow(CF) and the incidence of malignant arrhythmia after ischemia-reperfusion In this experiment, the isolated rat hearts were submitted to 30 min of global no-flow ischemia, then followed by 30 min of reperfusion. The hearts were divided randomly to 4 groups: normal control group, ischemia-reperfusion group, 450mg/kg QDPTP group, 900mg/kg QDPTP group. We took the electrocardiogram continuous and analysed its arrhythmia, CF and LVDP were measured according to time point to analyse their recovery rate. Result: high dosage QDPTP could significantly antagonize the decrease of LVDP and CF induced by I/R. Malignant arrhythmia incidence in QDPTP group was lower than in I/R group. Conclusion: QDPTP can protect myocardium from I/R injury.2. The effect of QDPTP on SOD activity and MDA content in myocardial homogenateThe model and group are the same as above. Taking about 150mg of left ventricular myocardial at the end of the experiment and making it into homogenate, and the activity of SOD and content of MDA were tested respectively. Result: In high and low dosage QDPTP, the activity of SOD were obviously higher and content of MDA were obviously lower (P<0.01), but there is no dose-dependence relationship between these two groups. Conclusion: the possible mechanism of QDPTP are protecting endogenous antioxidase, eliminating free radical, inhibiting membrane lipid peroxidation.3. The influence of QDPTP on myocardial Bcl-2/Bax proteins expression and apoptosis in the heart tissue.By immunohistochemistry means, cadiocytes apoptosis and Bcl-2 and Bax protein expression in cardiocytes were detected. Result: QDPTP upregulated Bcl-2 expression and downregulated Bax expression dose-dependently and reduced myocytes apoptosis. Conclusion: QDPTP can protect the heart by inhibiting cadiocytes apoptosis.4. The effect of QDPTP on myocardial ultrastructure after reperfusionThe model and group are the same as above. Taking about 1mm3 of left ventricular myocardial at the end of the experiment and fixing it in glutaraldehyde. The ultrastructure of myocardial tissue was observed by the electron microscope. Result: high dosage QDPTP can attenuate ultrastructure injury of myocardial tissue compared to the I/R group. Conclusion: this also affirms the protection effect of QDPTP.Part II The effects of 3,5,4'-trihydroxy-trans-stilbene and 3,5,4'-trimethoxy-trans-stilbene on INa in guinea pig ventricular myocytesRES is a polyphenol compound, and its chemical name is 3, 5, 4'-trihydroxy-trans-stilbene. Lots of studies have proved that RES have strong protective effect on cardiovascular system, and the protective mechanisms involved antioxidize,inhibiting platelet aggregation, increasing the expression of eNOS and nNOS and elevating their activity, vasodilatation, inhibiting vascular smooth muscle cell proliferation and cadiocytes hypertrophy caused by AngII and endothelin. Some reported that RES have inhibitory effect on calcium current in guinea pig ventricular myocytes. 3, 5, 4'-trimethoxy- trans-stilbene (TMS) is the derivate of RES, and it have also pharmacological effect similar to RES, such as resisting angio-proliferation, anti-inflammatory and anti-anaphylaxis, anti-tumor and so on. Respecting that RES and TMS are similar in chemical constitution and pharmacologic action, we investigate if RES and TMS have similar effect on sodium current(INa) in guinea pig ventricular myocytes, and observe if they exert direct actions on the heart and thus potentially contribute to cardioprotection.1. Effects of RES on INa in guinea pig ventricular myocytesSingle cardiac myocytes were isolated by enzyme, and the effects were assessed by applying whole-cell patch clamp technique. RES(10,30,100μmol?L-1)was shown to inhibit INa of guinea pig ventricular myocytes in a concentration dependent manner, and the inhibition ratio of 30, 100μmol?L-1 was 14.5±1.5%(n=5,P<0.005)and 56.6±7.9%(n=5,P<0.001), respectively. The maximal activating voltage of INa was not changed. RES acted quickly (about 3 min) and its effects were reversible completely after a 10min washout. For activation, V1/2 and S were -40.4±4.4mV and -6.3±0.4mV for control and -41.8±4.1mV and -5.8±1.2mV in 100μmol?L-1 RES. For availability, V1/2 and S were -89.3±2.0mV and 5.2±0.5mV for control and -100.7±3.3mV (P<0.005) and 5.6±0.8mV in 100μmol?L-1 RES.2. Effects of TMS on INa in guinea pig ventricular myocytesThe method was as before. TMS(10μmol?L-1)was shown to inhibit INa of guinea pig ventricular myocytes and acted quickly (about 3 min), and the inhibition ratio was 36.8±5.6%(P<0.005)in 10 mins, and its effects were reversible completely after a 10min washout. 1, 3μmol?L-1 TMS didn't affect INa. The maximal activating voltage of INa was not changed. For activation, V1/2 and S were -38.9±1.4mV and -6.0±0.4mV for control and -47.3±1.3mV(P<0.001)and -5.2±0.7mV in 10μmol?L-1 TMS. For availability, V1/2 and S were -87.0±3.3mV and 4.9±0.3mV for control and -96.7±3.5mV(P<0.001)and 5.4±0.3mV(P<0.01)in 10μmol?L-1TMS .In conclusion:1. QDPTP can protect myocardium from I/R injury. The possible mechanism are protecting endogenous antioxidase, eliminating free radical, inhibiting membrane lipid peroxidation and resisting cell apoptosis2. RES and TMS can exhibit direct inhibitory effects on INa in guinea pig ventricular myocytes and act rapidly, and the effect of RES derivative TMS is stronger than RES.