| Objective: To observe the effects of aqueous extract and flavonoids of persimmon leaf on the myocardial contractility in isolated rat heart, as well as to observe their effects on the inotropic action of norepinephrine (NE) and isoprenaline (ISO). Methods: First, isolated rat hearts were prepared using Langendorff-perfusion. Then, the effects of aqueous extract and flavonoids of persimmon leaf on myocardial contractility were observed by MS 4000U bio-signal analytical system. The next step was to observe their effects on the myocardial contractility after the administration of NE and ISO. Results: Aqueous extract and flavonoids of persimmon leaf could significantly decrease the myocardial contractility (P<0.05 or P<0.01) of isolated rat hearts; however, they didn't affect the inotropic action of NE and ISO. Conclusion:Aqueous extract and flavonoids of persimmon leaf have the negative inotropic action, but have no correlation withα- orβ- receptor. Objective: To observe the effects of aqueous extract and flavonoids of persimmon leaf on the hemodynamics of normal isolated rat hearts. Methods: First, isolated rat hearts were set up by using Langendorff-perfusion. Then, the effects of aqueous extract and flavonoids of persimmon leaf on the cardiac hemodynamics including HR, AP, LVSP, LVEDP, +dp/dtmax and-dp/dtmax in normal isolated rat hearts were investigated by MPA-cardiac function acquisition and analytical system (MPA-CFS). Results: Compared with NC group, high-, medium-dose PLA groups and high-, medium-dose PLF groups were found to slow HR and reduce AP, LVSP, and±dp/dtmax significantly (P<0.01 or P<0.05); however, there was no remarkable effect on LVEDP observed (P<0.05). Conclusion: The persimmon leaf extracts have the effects of negative myodynamia and negative frequency. Objective:To study the protective effects of aqueous extract and flavonoids of persimmon leaf on myocardial ischemia-reperfusion (I/R) injury in rats. Methods: The isolated rat hearts were set up by Langendorff-perfusion system. Myocardial ischemia-reperfusion injury was then induced by a 30-minute global ischemia followed by another 30-minute reperfusion. The following biochemical and physiological properties including HR, CF, LVSP, LVEDP, +dp/dtmax and -dp/dtmax were investigated by the MPA-cardiac function acquisition and analysis system (MPA-CFS). In addition, the activities of superoxide dismutase (SOD), Na+-K+-ATPase and Ca2+-ATPase, glutathione peroxidase(GSH-Px), and the content of malondialdehyde (MDA) in myocardial tissues were determined. Meanwhile, the activities of aspartic transaminase(AST), creatine kinase (CK), creatine kinase isoenzyme MB(CK-MB), lactate dehydrogenase (LDH) and lactic dehydrogenase-1(LDH-1) in coronary perfusion flow were also measured to assess the injury of the myocardial cells as well as the protective effects. Additionally, the pathology of myocardium and the expression of apoptosis associated proteins including Bcl-2 and Bax were analyzed. Results: High dose of aqueous extract and flavonoids were found to significantly decrease HR,CF,LVSP,±dp/dtmax and reduce LVEDP (P<0.01 or P<0.05). In addition, high dose of aqueous extract and flavonoids were found to significantly reduce the releases of AST, CK, CK-MB, LDH, LDH-1 from I/R rat hearts, increase the activities of SOD, Na+-K+-ATPase, Ca2+-ATPase and GSH-Px, and decrease the MDA product significantly (P<0.01 or P<0.05). Moreover, the histopathological examination confirmed that the degree of the myocardial injury in high dose of aqueous extract and flavonoids was obviously lessened when compared with I/R group, which also indicated that aqueous extract and flavonoids could down-regulate the expression of Bax (P<0.01) and significantly increase the ratio of Bcl-2/Bax(P<0.01). Conclusion:Aqueous extract and flavonoids of persimmon leaf have the myocardial protective effects against I/R injury, which may be related to attenuating the free radicals.
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