The Research Of Extracellular Histone Damage To Heart And Brain And The Intervention

Objective:Study the role of extracellular histone in cerebral ischemic reperfusion as well as its mechanism and the cell toxicity effect of histone on myocardial.Heparin is used to study the protective effect against cytotoxicity of extracellular histone.To review the clinical use of Centrifugal Ventricular Assist Device（VAD）and Extracorporeal Membrane Oxygenation（ECMO）in Shanghai Children’s Medical Center.Methods:Part one:Twenty male Sprague Dawley（SD）rats were used to establish transient middle cerebral occlusion（t MCAO）model,and rats were divided into 2groups randomly named group A and group B,then saline and heparin were injected respectively.The brain tissue was taken after the test of behavioral score 24 hours later,and the infarction area was calculated after the dyeing.Six male SD rats were divided into 3 groups randomly and one group was established the t MCAO while another group was shame group and the last group was the control.Cardiac perfusion was operated after 24 hours and brain tissue was taken,followed with histone antibody and microglia specific antibody fluorescence staining.SD fetal rat cortical neurons were cultured,and calf thymus histone was added to cell wells and the viability of neurons was tested after 1 hour,followed with electron microscope scanning.The cultured neurons were taken into 2%O₂ incubator and takeout after 24hours or 48 hours,followed by histone antibody fluorescence staining.Part two:Fifteen C57BL/6 mouse were divided into 3 groups randomly named A、B、C.Group A was no injection as control and group B was injected with 60mg/kg histone while group C was injected with 60mg/kg histone together with 50mg/kg heparin,heart function of all mouse were tested 4 hours later.Newborn C57BL/6mouse cardiomyocytes were cultured,followed by different dose of histone（50-1000μg/m L）added and the viability of cell was tested.Five cell wells were selected and added 200μg/m L histone,and different dose of heparin were added,then the change of cell viability was tested.Part three:From January 2005 to December 2015,60 cases supported by centrifugal pump ventricular assist（VAD）or extracorporeal membrane oxygenation（ECMO）in Shanghai children’s medical center were retrospectively analyzed.Results:Part one:In t MCAO model,the brain infarction area of group B was decreased significantly than group A（p<0.001）,and behavioral score of group B was increased than that of group A.H₃ was increased in cerebral infarction and microglia cell was activated in t MCAO model.The cell viability of neurons that added CTH was decreased significantly（p<0.001）and scanning electron microscope showed the cell membrane of control group was smooth while the CTH group was shrinking and death.In histone antibody staining showed that histone was distributed out the nuclear when cultured in hypoxic box 24 hours,and 48 hours,suggesting that H₃ was released by neurons when O₂ was not enough.Part two:The left ventricular ejection fraction（LVEF）of group B was decreased significantly than that of group A（p<0.001）while LVEF of group C was increased than that of group B（p<0.01）.the cell viability was decreased when CTH added to cultured cell.And the viability of cardiomyocytes was no different significantly than control when added heparin to cell wells.Part three:The duration for VAD was from 3 to 458 hours.Twenty-two cases were weaned from the devices and 20 were successfully discharged.The duration for ECMO was from 26 to 498 hours.Sixteen cases were weaned from the devices and 14were successfully discharged.None was survived in VAD-ECMO group.The ALCAPA cases had the biggest ratio in VAD group,and the survival rate was 81.82%.Conclusions:The histone is the key factor in brain injury/reperfusion,and is released by neurons during hypoxic-ischemic.Heparin may be the appropriate antagonist to histone.The histone has direct toxic to cardiomyocytes and decreased the heart function.Heparin may attenuate the toxic effect of histone.Pediatric patients with cardiac failure are suitable to be supported by VAD and ECMO.The cardiac function,respiratory function,age,complications and costs should be considered when choosing these two methods.