The Application Of Supercooling Technique In Mouse Heart Preservation Study

Background.Heart transplantation is considered the only optimal therapy for the treatment of various end-stage heart diseases.The short heart preservation time is a major limitation to the clinical application of heart transplantation.Currently,conventional 4 ? low temperature,static storage in UW solution is the gold standard for the preservation of donor organs in a variety of clinical organ transplantation.Supercooling preservation techniques store a donor organ below 0 °C without freezing.This has great advantages in inhibiting organ metabolism in comparison to conventional preservation at 4 °C,and theoretically has a longer preservation time and better preservation effect.We developed a novel supercooling technique,using a liquid cooling apparatus and novel preservation and perfusion solutions,which yielded a stable-8 °C supercooling preservation state.The purpose of this study was to evaluate the maximal preservation time and preservation effect of our supercooling preservation technique in a mouse heart transplantation model.Methods.Syngeneic heterotopic heart transplantation was performed in three groups of mice:(1)the non-preservation group,in which the cardiac grafts were transplanted immediately after harvesting;(2)the conventional UW group,in which the cardiac grafts were stored in UW solution at 4°C for different periods of time;and(3)the supercooling group,in which the cardiac grafts were stored in a novel supercooling preservation solution at-8°C for different periods of time.The maximal preservation time was investigated.Twenty-four-hour sample data were collected and analyzed to compare the heart graft protection effect of supercooling to conventional UW preservation at 4°C.Results.Our technique yielded a stable-8 °C supercooling preservation state,and cardiac graft revival was successfully achieved after preservation for 144 h,long-term survival was observed after preservation for 96 h.However,in the conventional UW group,cardiac graft revival was achieved after preservation for up to 48 h,long-term survival was observed after preservation for up to 24 h.The preservation outcomes,including rebeating time,ATP level,myocardial enzyme release,inflammation,neutrophil infiltration,myocardial ultrastructure,myocardial edema,ischemiareperfusion injury,oxidative stress and myocardial apoptosis,were also improved in the supercooling group.Conclusions.Supercooling heart preservation at-8 °C greatly prolonged the preservation time and improved the post-transplant outcomes in comparison to conventional 4°C UW preservation.Our study shows that supercooling preservation is a promising technique for organ preservation,but further technical improvement and research are still needed.