The Protective Effects Of Hydrogen Sulfide On Isolated Rat Hearts During Hypothermic Preservation

The effect of donor heart protection is of one of the main factors which affect heart transplantation success or not. To improve the effect of donor heart preservation is always an important topic in the heart transplantation. Hyperpolarized myocardial preservation solution is also a hot research topic. But because of the specificity of heart transplantation, up to now, the time latitude of hypothermic preservation of donor heart is still limited in 4 to 6 hours. With the development of heart transplantation in the word, shortage of donor heart and its short preservation time limit restricts the development of heart transplantation seriously. Enhancing protective effect including prolonging time limit and increasing preservative quality of donor heart is very important to heart transplantation. Researches in recent years indicate that endogenous hydrogen sulfide likes nitrogen monoxidum and carbon monoxide is a internal gas signaling molecule, and also a kind of ATP-sensitive potassium channel opener. Eric's experiments indicate that exogenous hydrogen sulfide can induce a suspended animation-like state in mice in which a decrease in metabolic rate (MR) is followed by a reduction in core body temperature (CBT). This research is a preliminary exploration about hydrogen sulfide's protective effect in isolated heart preservation by adding sodium hydrosulfide (a donator of hydrogen sulfide). Langendorff perfusion apparatus was used in the experiment for myocardial functional evaluation before and after preservation. Myocardial enzyme (CK, LDH) leakage,wet weights in myocardium, cardiac light microscope and ultrastructure were measured after reperfusion.1. Contrast research of protective effects of hydrogen sulfide on isolated rat hearts during hypothermic preservationObjective To observe the protective effects of hydrogen sulfide on isolated rat hearts. Methods Forty-eight SD rats were randomly assigned to two groups : Control group(ST group) , the hearts were arrested with St.Thomasâ…¡solution and preserved in the same solution ( n = 24) ; HST group ,the hearts were arrested with St.Thomasâ…¡plus hydrogen sulfide (H₂S) solution and preserved in the same solution (n = 24). All rat hearts were preserved for 4, 6 and 8 h with 4℃hypothetmia, and underwent 30 min reperfusion (37℃).The isolated hearts were perfused on the Langendorff perfusion apparatus for functional evaluation before and after preservation. Myocardial enzyme (CK, LDH) leakage,wet weights in myocardium and cardiac ultrastructure were measured after reperfusion. Results After the hearts were preserved for 4 h and 6 h, the differences of the recovery of myocardial function and wet weights in myocardium were insignificant but the differences of creatine kinase(CK) and lactic dehydrogenase (LDH) were significant between HST and ST group. After the hearts were preserved for 8 h, the differences of all target measured were significant between HST and ST group. Conclusions Addition of H₂S into the St.Thomasâ…¡solution could enhance the myocardial protective effects to the isolated rat hearts.2. Result research of protective effects of hydrogen sulfide on isolated rat hearts during hypothermic preservationObjective To investigate the protective effects of St. Thomasâ…¡solution containing H₂S on isolated rat hearts. Methods Thirty-two isolated rat hearts were randomly divided into four groups (n=8 each) and the hearts were arrested with St.Thomasâ…¡plus hydrogen sulfide solution and preserved in the same solution for 4, 6, 8 and 10 h with 4℃hypothermic. 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 Along with the extension of preservation time , the recovery of myocardial function had got lower and myocardial enzyme leakage upper gradually.Cardiac ultrastructure presented a minor injury after the hearts were preserved for 4 and 6 h and present a secondary injury after 8 and 10 h. But after reperfusion ,the difference of the recovery of myocardial function was significant between 8 h group and 10 h group. Conclusions The myocardium tissue would appear secondary injury after the isolated hearts were preserved in St.Thomasâ…¡solutions containing H₂S for 8 h and 10 h. The function of the heart would be serious impaired afer preserved for 10 h, but the whole preservative effect would be in 8 h.Our results indicates that addition of H₂S into the St.Thomasâ…¡solution combined with hypothermic preservation could enhance the myocardial protective effects to the isolated rat hearts. High potassium and low temperature can make the heart be arrested quickly, reduce the consumption of the myocardial energy, be advantageous to the protection of the myocardial, and limit its adverse effects. This can prolong the time of heart preservation, thus enhance the myocardial protective effects. As for the best effective density of H₂S still need further experimental investigation.