Ultrastructural change of isolated rat hearts after hypothermic preservation by St.Thomas II solutions containing H_2S

AIM To investigate the ultrastructural changes of isolated rat hearts after hypothermic preservation by St.Thomas Ⅱ solutions containing H2S for different periods of time and reperfusion for 30 minutes.METHODS Thirty-two isolated rat hearts were randomly divided into four groups(n=8 each) and the hearts were arrested with St.Thomas Ⅱ plus hydrogen sulfide solution and preserved at 4℃ hypothermically in the same solution for 4 h,6 h,8 h and 10 h.The isolated hearts were perfused on the Langendorff perfusion apparatus for functional evaluation before and after preservation.Myocardial enzyme leakage and cardiac ultrastructure were measured after reperfusion.RESULTS The recovery of myocardial function decreased with the extension of preservation time and myocardial enzyme leakage increased gradually.Cardiac ultrastructure presented a minor injury after the hearts were preserved for 4 h and 6h and presented secondary injury after 8 h and 10 h.After reperfusion,the difference of the recovery of myocardial function was significant between 8 h group and 10h group.CONCLUSION When isolated hearts are preserved in St.Thomas Ⅱ solutions containing H2S,the hearts could be well preserved within 8 h preservation.Secondary injury of myocardium tissue would appear after 8 h and 10h preservation and the function of the heart would be seriously impaired after 10h preservation.