| Background:In China,the morbidity of cardiovascular disease is consistently growing and the number of patients with end-stage heart failure is also expanding.Although heart transplantation is an effective therapy to cure end-stage heart diseases,the shortage of donor hearts limits the broad application of heart transplantation.Donation from circulation death(DCD)can expand the donor heart pool but the clinical outcome of heart transplantation is not perfect due to the severe warm ischemia reperfusion injury for DCD heart.Recent study has discovered that NLRP3 inflammasome plays an essential role in cardiac ischemia reperfusion injury(IRI).As a novel NLRP3 inflammasome inhibitor,mcc950 has been applied for some cardiovascular diseases such as atherosclerosis and myocardial infarction.Object:(1)To establish the model of donor heart suffered from warm ischemia injury,of normothermic machine perfusion for donor heart and of abdominal heart transplantation.(2)To verify NLRP3 inflammasome is involved in warm ischemia reperfusion injury in donor heart.(3)To verify mcc950 protects the donor heart from warm ischemia reperfusion injury by inhibiting the production of NLRP3 inflammasome.Methods:(1)To induce cardiac ischemia injury by 15 minutes of warm ischemia time.To establish normothermic machine perfusion and to mix blood from rats with crystal solution to be perfusate.After 90-minute perfusion,cardiac function was measured by balloon-catheter and pressure conduction system.To establish abdominal ectopic heart transplantation model and to perfuse the donor heart in vivo for 90 minutes then heart tissue was collected.(2)The donor rats were randomly divided into control group and warm ischemia reperfusion group.The hearts in control group were harvested directly without suffering from ischemia reperfusion injury.In warm ischemia reperfusion group,the hearts were suffering 15 minutes of warm ischemia.The differences on the protein expression of NLRP3 inflammasome,oxidative stress,inflammation and apoptosis between the two groups were compared by immunohistochemistry,immunofluorescence and western blotting.(3)There were three groups of donor rats,vehicle group,mcc950 applied in machine perfusion group(MP)and mcc950 applied in machine perfusion and after operation group(MP+PO).In MP group and MP+PO group,mcc950 was added in perfusate both.In MP+PO group,mcc950 was also injected through left jugular vein.Cardiac function was assessed 90 minutes after transplantation.The protein expression of NLRP3 inflammasome,oxidative stress,inflammation and apoptosis was also evaluated.Results:(1)The model of donor heart warm ischemia,normothermic machine perfusion and abdominal ectopic heart transplantation was successfully established and was used for verifying protective effect on donor heart.Totally 15 experiments of the model were carried out and the success ratio is 73.3%.The average transplantation time was 52±6 minutes and the average re-beating time of donor hearts in vivo was 93±31 seconds.The cardiac function was successfully assessed by balloon-catheter and pressure conduction system.(2)Compared with control group,the protein expression of NLRP3 inflammasome,oxidative stress,inflammation and apoptosis in warm ischemia reperfusion group was significantly increased.(3)In MP group and MP+PO group,treatment with mcc950 significantly improved cardiac function,including developed pressure,dP/dtmax and dP/dtmin,which was measured 90 minutes after transplantation.Compared to Vehicle group,the application of mcc950 both in perfusate and after transplantation can notably ameliorate NLRP3 inflammasome,oxidative stress,inflammation and apoptosis in donor hearts.Conclusion:Normothermic machine perfusion combined with mcc950 treatment can be a promising and novel DCD heart preservation strategy,which can alleviate myocardial IRI via inhibiting NLRP3 inflammasome. |
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