| Background: Incidence rate of coronary atherosclerotic heart disease(CHD) is about 58.36%. About 1/3~1/2 death are resulted from CHD and in 50%~75% dead patients which were caused by heart diseases, CDH is involved. The cardioprotection of delayed preconditioning is effective to prevent heart from I/R injury and it is helpful to find a medicine to replace the ischemic preconditioning and become a new and effective therapeutic mathods.Purpose: To search an effective traditional Chinese medicine to mimic delayed preconditioning and research for the delayed myocardioprotection of allitridi pretreatment and the mechanisms of cell signal trasduction.Methods: Experiments on conscious animals: Thirty-two conscious New Zealand white rabbits underwent the following protocol. On day 1, rabbits were randomly divided into four experimental groups(n=8/group): I/R group(saline, iv), IPC group(four 5 min coronary artery occlusion/5 min reperfusion cycles), APC1 group(allitridi 1mg/kg, iv) and APC2 group(allitridi 0.5mg/kg,iv).On day 2, rabbits were subjected to 30 min of global ischemia followed by 120 min reperfusion. The percentage of the weight at risk and at infarction was determined by triphenyltetrazolium chloride staining. Hemodynamic values (HR, LVEDP, LVPSP, CF, ±dp/dt max) were registered by RM6004 multichannel recording and analyzing system, myocardial morphological changes were observed by electron microscope and LDH, CK, MDA, MnSOD were measured.Experiments on cultured cells: Cell viability , LDH, MDA were measured to decide the severity of Hypoxia/Reoxygenation(H/R) injury on Neonatal Rat Myocardiocytes. ①Study on the dose-response relation: Observe the effects of allitridi(5, 10, 20μg/ml) preconditioning on 2 h H/2 h R injury. ②Study on the time-response relation: Observe the improved effects of allitridi pretreatment 12 h, 24 h, 36 h before 2 h H/2 h R. ③Study on the effects of inhibitors of signal transduction: Observe the effects of inhibitor of PKC H-7 and inhibitor of MAPK PD98059 on delayed myocardioprotection of allitridi(20μg/ml), furthermore, study on the mechanisms of signal transduction of allitridi: measure the expression of PKC-ε, HSP70 and NF-κB by western immunoblotting 24 h after preconditioning by allitridi, with or without H-7 and PD98059.Results: experiments on conscious animals:①The infarct-to -risk ratio were significantly limited in allitridi(1mg/kg) treated rabbits from 52.9±6.5% in I/R group to 36.7±5.5%(P<0.05). ②Allitridi preconditioning (0.5,1mg/kg) could decrease the LVEDP at the end of reperfusion 32.34% and 56.56% respectively(P<0.05 or P<0.01), increase LVPSP 61.58% and 94.33% respectively(P<0.05), increase +dp/dt max 19.94%, 49.84% respectively (P<0.05), and -dp/dt max 24.17%, 51.33% respectively(P<0.05 or P<0.01). But HR and CF were not significantly different between groups during the experiments. ③The cell and mitochondria tended to swell as well as the endothelia cells , and the structures of cardial fibin were unclear in the I/R rabbits which were greatly improved in allitridi-treated rabbits. ④Plasma LDH activity in allitridi preconditioning(0.5,1mg/kg) hearts were 30.51%,34.96% less respectively, compared with I/R group(P<0.05) and homogenate MDA were 23.74% ,21.72% less respectively(P<0.01).Experiments on cultured cells: ①Compared with the cardiomyocytes unconditioned, the cell viability treated by 5, 10, 20μg/ml allitridi (86.01%, 87.45%, 94.42% VS 76.65%, P<0.01) were greatly increased, but in 50μg/ml allitridi group(38.34%) was significantly less than I/R group. ②Cell viability was greatly increased at 12 h and 24 h(70.03%, 77.14% VS 65.16%) compared with I/R group(P<0.05 or P<0.01). ③cardiopretection which was induced by allitridi(20μg/ml) was abolished by H-7 and PD98059 respectively. ④Western immunoblotting revealed up-regulation of PKC-εand HSP70 synthase protein 24 h after allitridi administration which also suppressed by H-7 and PD98059. There are no changes in NF-κB protein levels.Conclusion: allitridi ca...
|
PDF Full Text Request