ObjectiveTo study the changes of levels of α subunits of stimulatory (Gsα) and inhibitory guanine nucleotide binding protein (Giα) in newborn guinea pig (0 2 days old) myocardium undergoing global ischemic reperfusion, and influences on the changes by St.Thomas Ⅱ and cold blood cardioplegic solution.MethodsThirty newborn guinea pigs were randomly assigned to three groups. GroupⅠ ( n = 10): the newborn hearts suffered by hypothermic global ischemia; group Ⅱ( n =10): the newborn hearts arrested by St. Thomas Ⅱ , and group Ⅲ ( n = 10): the newborn hearts arrested by cold blood cardioplegic solution. Levels of Gsα and Giα were investigated with Western blot analysis.ResultsNo differences of levels of Gsα and Giα were found in three groups before ischemia ( P gt;0.05). The level of Gsα after ischemia was significantly decreased than before ischemia in groupⅠand group Ⅱ ( P lt; 0 01), whereas no pronounced changes in group Ⅲ ( P gt;0.05) were noted after ischemia. The level of Gsα in group Ⅲ was not significantly changed after reperfusion compared with before ischemia( P gt;0 05), and it was much higher than those in groupⅠand group Ⅱ ( P lt; 0 01). Level of Giα was found not markedly changed in group Ⅲ after reperfusion compared with that before ischemia, but was notable higher in groupⅠand group Ⅱ( P lt;0.01). ConclusionsSignificant decrease of level of Gsα, whereas marked increase of level of Giα are found in myocardium of newborn guinea pig undergoing hypothermic (20℃) ischemic reperfusion. No impact of St. Thomas Ⅱ on these changes is verified, but recovery to the level of Gsα and Giα before ischemia is achieved by cold blood cardioplegic solution after ischemia and reperfusion. Unbalance between Gsα and Giα is the one of the mechanisms of ischemic reperfusion injury for immature myocardium.
Objective To investigate the effect of polyethylene glycolbovine hemoglobin (PEG-bHb), which was used as an oxygen carrier in cardioplegic solution, on the protection of isolated rat hearts. Methods The hearts of 32 male SD rats were harvested and transferred to Langendorff circuit. They were divided into 4 groups according to cardiocplegia: St.Thomas group (group A), 1∶2 PEG-bHb group (group B), 1∶4 PEG-bHb group (group C) and 1∶8 PEG-bHb group (group D). After 20min balance period, hearts were perfused with cold (4℃) cardioplegic solutions, and preserved at 30℃ for 60min, then reperfused. Levels of cardiac troponin I (cTn I) and adenosine triphosphate(ATP) contant in coronary effuent were detected, and ultrastructures of myocardium were observed. Results After reperfusion, cTn I contant of group A were higher (F=52.955,Plt;0.05) and ATP contant were lower (F=68.757,Plt;0.05) than those in group B, group C and group D. Myocardial water contant were lower in group B and group C(F=3.048,Plt;0.05). Conclusion PEG-bHb in cardioplegic solutions can provide better myocardial protection during ischemia.
Objective To investigate the protective effects of cardioplegic solution with creatine phosphate on donor heart preservation in rats, and the possibility of prolonging outofbody heart preservation in lack of blood supply to improve on transplantation quality. Methods Twenty Wistar rats were randomly divided into two groups, control group (n=10): pure St.ThomasⅡ cardioplegic solution was perfused to protect donor hearts; experimental group (n=10): St.ThomasⅡ cardioplegic solution with 2.5g/L sodium creatine phosphate was perfused to protect donor hearts. After 4 hours of refrigerated preservation, myocardial tissues were tested for adenosinetriphosphate(ATP) level and super oxide dismutase (SOD) activity. Cardiac ultrastructure and mitochondria swelling condition were monitored with light and electron microscopes. Results After the 4hour low temperature preservation of donor hearts, ATP content in experimental group cardiac tissue was significantly higher than that in control group (2.75±0.99μmol/mg vs. 1.77±0.86μmol/mg, Plt;0.05); SOD in experimental group cardiac tissue was significantly higher than that in control group（49.6±2.52 U/mg vs. 45.27±2.21 U/mg，Plt;0.05）. Electron microscopic inspection demonstrates that in the control group, chromatin condensed and dissolved inside the nuclear membrane; mitochondria ridge gap disappeared; myocardial cell pyknosis and mesenchymal vascular endothelia necrosis appeared. In contrast, myocardial cell nuclei remained in the center; sarcomere band structure was distinct; sarcoplasmic reticulum expanded and intercalated disk band structure was clear in experimental group. Conclusion Cardioplegic solution with creatine phosphate is able to enhance donor heart myocardial protection significantly.
Objective\ In order to assess and evaluate the clinical results of cold blood cardioplegia and intermittent cross clamping as myocardial preservation in coronary artery bypass grafting(CABG).\ Methods\ According to the management methods, 2 013 cases for elective, isolated CABG were divided into two groups at St.George’s Hospital, London.Cold blood cardioplegia group: 596 patients treated with cold blood cardioplegia, and hypothermic ventricular fibrillation group: 1 417 patients treated with intermitt...