The Study Of Cardioprotective Effects Of Reperfusion Initial Period Increasing Perfusion Pressure On Isolated Rat Heart Suffering From Ischemia And Reperfusion

BacgroundMyocadrial ischemia reperfusion injury(MIRI) is one kind widespread and the complex pathology physiological process。At the right moment reperfusion can save the cardiac muscle ischemia the damage,But ischemia the cardiac muscle blood stream to restore uninterruptedly suddenly actually aggravates the ischemia damage namely reperfusion injury。In the mid-1980s,Murry and so on proposed the cardiac muscle after undergoing the short ischemia reperfusion many times,Can retard and reduce the cardiac muscle damage in afterward long time ischemia,Namely Ischemia Preconditioning(IPC)。Although IPC is prevents IRI one endogenous modus operandi,But because it needs to enforce before the ischemia,On the clinical majority cardiac muscle ischemia event unpredictable as well as ischemia the ischemic preconditioning implementation process itself to have creates the nature,Therefore the IPC clinical practice in fact is restricted。In 2003,Discoveries and so on after before Zhao fall the dog heart's left coronary artery,to tie up 1h,,is redundant clears 30s,to tie up 30s again,The so continual 3 circulations,restore the coronary artery blood stream afterward,May cause the cardiac arrest scope to compare the control group to reduce approximately 44%,After this he proposed for the first time "Ischemia Postconditioning"(IPO) concept。Because ischemia postconditioning,adapts the simplicity of operator,the opportunity easy to grasp,and may apply in the known cardiac muscle ischemia event,therefore has the more direct clinical practice value。This was also one of recent years cardiac muscle protection area research hot spots。And some research indicated when after the heart stops wrestles,reperfusion,the early perfusion pressure and the current capacity to the coronary artery bast function's influence are really big,the excessively high perfusion pressure will press and the oversized perfusion discharge will possibly damage the coronary artery bast or the influence cardiac muscle protection effect。Ischemic postconditioning,adapts is an additional ischemia intervention after all, whether to ischemia cardiac muscle existence latent threat,at present still did not have the conclusion,therefore,after ischemia postconditioning carries on the improvement, causes it more to be safe,easily by the clinical worker receive is very important。This experiment through establishes the isolated rat heart Langendorff ischemia postconditioning the perfusion model,the observation ischemia postconditioning to the rat isolated MIRI heart function,the coronary flow,the cardiac muscle injury and the ultrastructure influence,confirms IPO the endogenous mechanism;Verifies one kind of postconditioning the improvement method,we called "slow processing",after namely cardiac muscle ischemia and reperfusion,the control pours into when early the reperfusion pressure either the perfusion current capacity,cause to pour into the pressure or the current capacity again slow achieve the normal perfusion to press the level gradually,Is for the purpose of through this experiment,after discussing this kind of cardiac muscle ischemia reperfusion "slow processing" whether to have with the standard cardiac muscle ischemia postconditioning same cardiac muscle protection uses as well as its clinical practice latent possibility。Materials and Methods52 SD rats were randomly divided into 4 groups:normal control group(NC),ischemia reperfusion group(IR),ischemic postconditioning group(IPO),L-ischemic preconditioning group(L-IPC).Ischemia reperfusion injury was induced by 40 min of global ischemis and 120 min of reperfusion in isolated rat hearts.The cardiac functions,coronary flow(CF),cardiac troponin I(cTnI)content in coronary effluent,the heart stem area,the myocardial ultrastructure and the expression of P-Akt were studied.ResultsIn IPO and L-IPO group,the cardiac functions improved signifycantly,the contents of cTnI in coronary effluent were lower than that in IR group(p＜0.01),the heart stem area were small(p＜0.01),but CF were higher(p＜0.01),the activity of P-Akt increased(p＜0.01),.Meantime,myocardial ultrastructure damage alleviated significantly.The difference between L-IPO and IPO group was not significant(p＞0.05).Conclusion1.The results showed that L-IPO had well protective effects on the MIRI of the isolated rat heart.2.PI3K/Akt/GSK-3βthe circuit possibly is L-IPO to one of isolated rat heart MIRI protective function signal conduction circuits,and it is the same or similar toIPO mechanism.