The Influence And Function Mechanism Of Hyperbaric Oxygen Pretreatment On Myocardial Ischemia Reperfusion(MIR) Injury In Rats

In recent years,coronary atherosclerotic heart disease has become the major disease which is harmful to human health with a rising the trend of incidence.The World Health Organization (WHO) predicted that by 2020 cardiovascular disease would become the primary cause of death in the world and Acute myocardial infarction as the most serious coronary heart disease type would become a culprit undoubtedly.Openning occlusion blood vessels early could effectively restore myocardial blood reperfusion and save myocardial ischemic heart muscle effectively,but ischemic reperfusion injury caused by reperfusion may lead to further myocardial cell death and cardiac function obstacle.Hyperbaric oxygen has been widely used in clinical,and played a good effect in the treatment of many diseases.Objective:Observe and discusse the influence and function mechanism of Hyperbaric Oxygen Pretreatment on Myocardial Ischemia Reperfusion (MIR) Injury in Rats.Methods:A total of 45 male Wistar rats weighing 250-300 g were used,and rats were divided into three groups randomly:Control(con group),IR(IR group),HBOpre+IR(HBOpre group).Rats of HBOpre group were intermittently exposed to 100% 02 at 2.0ATA (where ATA is absolute atmosphere) for 1 h daily for7 d.The rats received intraperitoneal injection of 20% Urethane,hearts were excised and immediately connected to an aortic cannula,and then perfused at a constant pressure in a non-circulating Langendorff mode with Krebs-Henseleit buffer solution.we recorded the datas of HR,LVSP,±dp/dtmax for different periods by BL-420 Biological function system.After each experiment,we determined the activity of SOD and the quality of MDA,calculated myocardial infarction size with TTC dyeing,and observed the change of myocardial ultrastructure with HE dyeing.Last,we detected the expression of caspase-3,Bc1-2 and Bax in myocardial cells with immunohist-ochemical,and apoptosis index with TUNEL.Results:I.Before ischemia,HR of HBOPre group was a litter lower comp-ared with Control group and IR group with no difference(P>0.05);During reperfusion,HR of HBOPre group was much lower compared with Control group and IR group with significant difference(P<0.05);After 5min of reperf-usion,LVSP,±dp/dt of IR group and HBOPre group increased gradually with significant difference(P<0.05)2.Compared with IR group,the activity of SOD increased and the quality of MDA decreased in HBOpre group with significant difference(P<0.05).3.Compared with IR group, myocardium infraction size of HBOpre group reduced with significant difference(P<0.05).4.Light microsco-py:in Contro group, Cardiac structure was complete,clear,myocyte aligned loose,accidentally saw slightly inflammatory cell;in IR group, Myocardial cells were arranged irregular,cell cytoplasm swelling visible myocardial eosinophilic and enhance and there were lots of inflammatory cells; in HBOpre group,Myocardial cell lineaged more rules,cell slightly swollen visible myocardial cell cytoplasmic eosinophilic enhancement,with a little inflammatory cell.5.Compared with Control group,AI of IR group increased obviously(P<0.05); Compared with IR group,AI of HBOPre group decreased significantly(P<0.05).6.Immunihist-ochemical Results:Compared with Control group,the expression and apoptosis index of caspase-3 and Bax were significantly higher,the expression of Bcl-2 was reduced in IR group with significant difference(P<0.05); Compared with IR group,the expression and apoptosis index of caspase-3 and Bax were decreased,the expression of Bcl-2 was increased in HBOPre group with significant difference(P<0.05).Conclusions:1.Hyperbaric Oxygen Pretreatment played a role in the improvement of heart function by enhancing the ability of antioxidation,reduci-ng infarct size and inflammatory reaction.2.Hyperbaric Oxygen Pretreatment reduced cardiomyocyte apoptosis and MIRI by downer gulating the expression of caspase-3 and Bax and upregulating the expression of Bcl-2.