The Effect Of Persimmon Leaf Extract Against Myocardial Injury Induced By Ischemia Reperfusion Injury In Rats

Objective: To study the protective effect of water extract of persimmon leaf and persimmon leaf flavonoid on myocardial ischemia reperfusion injury in rats and its related mechanisms.Methods: SD rats with normal ECG were picked out and randomly divided into 9 groups with 10 rats (half male and half female) in each group: sham operation (SHAM) group, myocardial ischemia reperfusion (MIR) group, WPL low dose (WPLL) group, WPL medium dose (WPLM) group, WPL high dose (WPLH) group, PLF low dose (PLFL) group, PLF medium dose (PLFM) group, PLF high dose (PLFH) group, and positive drug (Ver) group. Different doses of drug were administered into duodenum 30 min before ligation of the left anterior descending coronary artery (LAD) for 30 min and followed with reperfusion for 60 min to establish MIRI model. The following indexes were determined at the end of reperfusion for 60 min. 1. MS 4000 was used to record HR, LVSP, LVDP, LVDEP, + dp/dtmax and -dp/dtmax. 2. The blood was collected via the abdominal aorta, centrifuged, and the upper serum was taken for detecting activities of AST, CK, CK-MB, LDH, LDH1, SOD and GSH-Px, and content of MDA in each rat. The myocardial ischemic tissues were taken for determining the activity of ATPase. 3. The blood was taken via the abdominal aorta, and centrifuged. The upper serum was collected for detecting the activity of nitric oxide synthase (NOS), and myocardial infarct size was assessed by TTC staining in each rat. 4. Myocardial ischemic tissues were taken to make histological section for observing the changes of histopathology of myocardium under optical microscope, and taking the pictures with camera simultaneously, and the Bcl-2 and Bax protein expressions were determined by immunohistochemical method.Results: Compared with MIR group, at 30min after reperfusion, HR in WPLM, WPLH, PLFM, PLFH and Ver group increased significantly (P<0.05), while the LVDP decreased significantly (P<0.05). At 60min after reperfusion, HR, LVSP and +dp/dtmax in WPLM, WPLH, PLFM, PLFH and Ver group increased significantly (P<0.05), while the LVDP, LVDEP and -dp/dtmax decreased significantly (P<0.05). 2. Compared with MIR group, persimmon leaf extracts could decrease the myocardial enzyme activity and the content of MDA in the serum significantly (P<0.01 or P<0.05), and increase the activities of SOD and GSH-Px in the serum significantly and the activity of ATPase in the myocardial ischemic tissues (P<0.01 or P<0.05). 3. Compared with MIR group, the myocardial infarct sizes were significantly smaller in WPLM, WPLH and PLFH group (P<0.01 or P<0.05). The content of NO and the activities of tNOS and cNOS in the serum in WPLM, WPLH, PLFM and PLFH group increased significantly (P<0.01 or P<0.05), while the activities of iNOS decreased significantly (P<0.01 or P<0.05). 4. Histopathological examination confirmed that, all the group of persimmon leaf extracts could lessen the degree of myocardial injury obviously compared with MIR group. Compared with the MIR group, the expression of Bc1-2 protein increased significantly in WPLM, WPLH, PLFM and PLFH group (P<0.01 or P<0.05), the expresion of Bax protein and the ratio of Bax protein to Bc1-2 decreased significantly (P<0.01 or P<0.05).Conclusion: Persimmon leaf extracts have the protective effects on myocardial ischemical reperfusion injury in rats, and show a certain dose-effect relationship. The mechanism may be related to anti-oxidation, protecting the activity of ATPase, increasing the activity of cNOS, decreasing the activity of iNOS, improving hemodynamics of heart, and inhibiting the cardiocyte apoptosis.