| Objective: Preliminary studies showed Bcl-2mediated skeletal muscleremote post-processing of the protective effect on the heart and Bcl-2-mediated cardioprotective effect by mKATPand mPTP regulation, mKATPandmPTP in the same reaction chain, mPTP migh be at mKATPdownstream.Thisstudy wanted to observe whether Bcl-2mediate protective effect of necroticmyocardium from rat ischemic post conditioning (PostC), whether thisprotective effect from PostC is mediated by mKATP, how the relative positionof Bcl-2with mKATPis, and whether this protective effect is regulated byneural.Method: Thirty healthy SD rats were randomly divided into5groups(n=6). After intraperitoneal injection of3%sodium pentobarbital (30mg/kg), after anesthesia open the thorax, the heart was removed quickly andimmersed0~4℃KH solution, gently extruding congestion, aortic intubation,and quickly hoisted the heart, the heart hanging on in vitro perfusion system,retrograde perfusion via the aorta (the whole process requires2mincompletion).After30minutes of balance perfusion, stopping irrigation for30minutes, and then2hours reperfusion produced ischemia-reperfusion model.Randomization as follows: Ischemia-reperfusion group (I/R), ischemicpostconditioning group (PostC) HA14-1+ischemia reperfusion group(HA14-1+I/R), HA14-1+ischemia group (HA14-1+PostC), HA14-1+5HD+ischemic postconditioning group (HA14-1+5HD+PostC). Which, HA14-1(2mg/Kg) is a selective inhibitor of Bcl-2; the5HD (5mg/Kg),5-hydroxytryptamine Jikui formate, a mitochondrial ATP-sensitive potassiumchannel blocker. Then detection range of infarcted myocardium by TTC. Usephysiological signal recording and analyzing system records the entireperfusion process center rate (HR), dynamic changes of left ventricular developed pressure (LVDP) and the maximal rate of rise of left ventricularpressure (dp/dtmax). Collection of coronary effluent, recording capacity ofcoronary effluent at the end of the equilibrated for30minutes, reperfusion for1minute,3minutes,5minutes,10minutes,20minutes,30minutes,1hour,2hours. And each time point within the coronary effluent CK and LDH’sactivity were measured.Results:1Observation of cardiac function and myocardial oxygen in the rat:1.1The change of HRAt the end of balanced perfusion for30minutes，that was the time beforeischemia: There was no significant difference between HR,(P>0.05).During ischemia for30min: the HR was decreased to disappear.At the end of reperfusion for2hours: compared with that before,ischemiathere was no significant difference between HR (P>0.05).1.2The change of HR×LVDPAt the end of balanced perfusion for30minutes，that was time beforeischemia: There was no significant difference between HR×LVDP,(P>0.05).During ischemia for30min: the HR×LVDP was decreased to disappear.At the end of reperfusion for2h: compared with perfusion of30min, eachHR x LVDP had a reducing trend, but this difference was not statisticallysignificant (P>0.05). There was no significant differences between groups ofcardiac work (P>0.05).1.3At the end of reperfusion for2h, recovery rate of dp/dtmax was comparedbetween groupsCompared with the I/R group, dp/dtmax recovery rate of PostC groupincreased significantly,47.10±7.26%vs27.77±12.76%, this trend wasstatistically significant (P＜0.05).Compared with the I/R group, dp/dtmax recovery rate of HA14-1+I/Rgroup has no significant differences,17.71±3.96%vs27.77±12.76%, P>0.05.Compared with the PostC group, dp/dtmax recovery rate ofHA14-1+PostC group was obviously reduced (28.79±2.62%vs47.10±7.26%, P＜0.05).Compared with the I/R group, dp/dtmax recovery rate of HA14-1+5HD+PostC group has no significant differences,24.09±4.98%vs27.77±12.76%,P>0.05.Compared with the PostC group, dp/dtmax recovery rate ofHA14-1+5HD+PostC group was obviously reduced (24.09±4.98%vs47.10±7.26%, P＜0.05).Compared with the HA14-1+PostC group, dp/dtmax recovery rate ofHA14-1+5HD+PostC group had a decreasing trend,24.09±4.98%vs28.79±2.62%, but this trend was not statistically significant (P>0.05).1.4At the end of reperfusion for2h, recovery rate of LVDP was comparedbetween every two groupsCompared with the I/R group, LVDP recovery rate of PostC group wasincreased,30.95±12.59%vs23.51±8.74%, but this trend was not statisticallysignificant (P>0.05).Compared with the I/R group, LVDP recovery rate of HA14-1+I/R grouphas no significant differences,17.33±4.91%vs23.51±8.74%, P>0.05.Compared with the PostC group, LVDP response rate of HA14-1+PostCgroup and HA14-1+5HD+PostC group was reduced,27.33±11.17%vs30.95±12.59%,20.67±12.17%vs30.95±12.59%, but this trend was nosignificant difference (P>0.05).Compared with the I/R group, LVDP recovery rate of HA14-1+5HD+PostC group has no significant differences,20.67±12.17%vs23.51±8.74%,P>0.05.1The arrhythmias observedDuring the balance perfusion in each group were not any arrhythmia.During reperfusion, the main arrhythmia ventricular premature beats,occurred before reperfusion within20min, not given any intervention, amongthe groups the incidence of arrhythmias was not significant different (P>0.05).2Determination of the degree of myocardial infarction This studyshowed that the myocardial infarction of I/R group, PostCgroup, HA14-1+I/R group, HA14-1+PostC group and HA14-1+5HD+PostCgroup respectively are41.98±3.16%,16.96±1.79%,25.25±4.59%,40.25±2.30%,40.78±10.20%.Compared with the I/R group,myocardial infarction of PostC group wassignificantly reduced (16.96±1.79%vs41.98±3.16%, P＜0.05).Compared with the I/R group, HA14-1+I/R group’s myocardialinfarction was not significant different,(40.25±2.30%vs41.98±3.16%, P＞0.05).Compared with the PostC group, myocardial infarction of HA14-1+PostC group significantly increased (25.25±4.59%vs16.96±1.79%，P＜0.05).Compared with the I/R group, HA14-1+5HD+postC’s myocardialinfarction was not significant different,(40.78±10.20%vs41.98±3.16%，P＞0.05).Compared with the PostC group, myocardial infarction ofHA14-1+5HD+PostC group was significantly increased (40.78±10.20%vs16.96±1.79%, P＜0.05).Compared with the HA14-1+PostC group,myocardial infarction ofHA14-1+5HD+PostC group was significantly increased (40.78±10.20%vs25.25±4.59%, P＜0.05).1Creatine kinase (CK) and Lactate Dehydrogenase (LDH) observationDynamic dynamic changes were observed between the different groupsduring ischemia and reperfusion myocardial enzyme LDH, CK release overtime in this trial.Before ischemia, LDH and CK levels had no significant differences (P＞0.05).LDH and CK activity in the coronary effluent during ischemia andreperfusion showed different levels, a significant difference compared withthe groups before ischemia (P＜0.05), gradually declined after reaching apeak within3-5min.On the first1min during reperfusion, compared with the I/R group, the CK activity of PostC group was significantly reduced,(38.44±5.43IU/mL vs79.98±28.32IU/mL, P＜0.05).On the first3min during reperfusion, compared with the I/R group, theCK activity of PostC group was significantly reduced,(71.62±15.38IU/mL vs120.82±35.52IU/mL, P＜0.05); compared with the PostC group, the LDHactivity of HA14-1+5HD+PostC group was significantly increased,(107.84±44.68IU/mL vs71.62±15.38IU/mL, P＜0.05).On the first5min during reperfusion, the activity of LDH in coronaryeffluent of the PostC group is significantly lower than the I/R group, the gaphave statistical significance（186.12±29.89IU/mL vs103.42±38.13IU/mL, P＜0.05）, compared with PostC group, the activity of LDH of HA14-1+PostC and HA14-1+5HD+PostC group has increased significantly（169.50±17.22IU/mL vs103.42±38.13IU/mL,182.60±10.47IU/mL vs103.42±38.13IU/mL, P＜0.05）.On the first10min during reperfusion, the activity of LDH of the PostCgroup is significantly lower than the I/R group,(86.47±37.80IU/mL vs173.86±35.79IU/mL, P＜0.05); compared with PostC group, the activity ofLDH of HA14-1+5HD+PostC group has increased significantly(174.80±15.79IU/mL vs86.47±37.80IU/mL, P＜0.05).On the first20min during reperfusion，the activity of LDH in coronaryeffluent of the PostC group is significantly lower than the I/R group,(64.46±14.07IU/mL vs150.41±22.98IU/mL, P＜0.05); compared withPostC group, the activity of CK of HA14-1+PostC group was increasedsignificantly,(65.2±11.95IU/mL vs38.94±14.81IU/mL, P＜0.05); comparedwith PostC group, the activity of CK of HA14-1+5HD+PostC group hasincreased significantly,(153.51±7.93IU/mL vs64.64±14.07IU/mL, P＜0.05).On the first30min during reperfusion, the activity of CK in coronaryeffluent of the PostC group is significantly lower than the I/Rgroup,(27.24±9.96IU/mL vs58.18±16.86IU/mL, P＜0.05);compared withPostC group，the activity of CK of HA14-1+PostC group has increased significantly, the gap have statistical significance (50.72±6.10IU/mL vs27.24±9.96IU/mL, P＜0.05), the activity of CK of HA14-1+5HD+PostCgroup has increased significantly,(61.38±26.06IU/mL vs27.24±9.96IU/mL,P＜0.05).Conclusions:1Bcl-2partially mediated the protective effect of the isolated heartduring ischemic post condition, this protective effect was not regulated byneural.2Bcl-2and mKATPmay located in the same reaction chain.3mKATPmay be located downstream of the Bcl-2. |
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