氨基酸对未成熟心肌保护作用的实验研究

Experimental Study of Protective Effects of Amino Acid Enriched Blood Cardioplegia on Immature Rabbit Heart

研究天门冬氨酸或（和）谷氨酸强化血停搏液对未成熟心肌的保护效果。将２４只出生３～４周新西兰幼兔随机均分成４组：Ｉ组为冷血停搏液组，Ｉ组天门冬氨酸（２０ｍｍｏｌ／Ｌ）强化组，ＩＩ组谷氨酸（２０ｍｍｏｌ／Ｌ）强化组，ＩＶ组谷氨酸加天门冬氨酸（各２０ｍｍｏｌ／Ｌ）强化组。结果表明，心功能指标心输出量（ＣＯ）恢复百分率ＩＶ组、Ｉ组明显少于Ｉ组（Ｐ＜０．０１）；左室收缩压（ＬＶＳＰ）恢复百分率Ｉ、ＩＩ、ＩＶ组明显少于Ｉ组（Ｐ＜０．０１）；左室舒张压（ＬＶＤＰ）及左室压力微分（ｄｐ／ｄｔ）恢复百分率Ｉ、ＩＩ、ＩＶ组优于Ｉ组（Ｐ＜０．０５）。乳酸脱氢酶（ＬＤＨ）和磷酸肌酶（ＣＫ）漏出量（Ｕ／Ｌ）中，ＬＤＨ漏出量Ｉ组优于Ｉ组（Ｐ＜０．０５），ＩＩ、ＩＶ组明显优于Ｉ组（Ｐ＜０．０１）；ＣＫ漏出量ＩＩ、ＩＶ组明显优于Ｉ组（Ｐ＜０．０１）。Ｉ、ＩＩ、ＩＶ组心肌含水量（％）明显优于Ｉ组（Ｐ＜０．０１）。Ｉ、ＩＩ、ＩＶ组心肌结构保护明显优于Ｉ组。结论：谷氨酸或（和）天门冬氨酸强化血停搏液能明显增强对未成熟心肌的保护作用。

Aim:This study was designed to evaluate the protective effects of amino acid enriched blood cardioplegia on immature rabbit heart.Material and method:Twenty four New Zealand rabbits(3 to 4 weeks old)were randomly divided into four groups(n=6 each group).Isolated working rabbit model was subjected to this study.Group I received cold blood cardioplegic solution.Group II received same cardioplegic solution as group I with addition of aspartate(20mmol/L).Group III with addition of glutamate(20mmol/L)and group IV receive cardioplegic solution with both aspartate and glutamate(20mmol/L each).The left ventricular function including left ventricular systolic pressure(LVSP),left ventricular diastolic pressure(LVDP),cardiac output(CO) and dp/dt max were recorded.The levels of creatine phosphokinase(CK),Lactic dehydrogenase(LDH)in coronary sinus venous blood and cardiac water content and ultrastructural changes of myocardium were measured.Result:Before myocardial ischemia,there were no significant differences in all above mentioned parameters in four groups.Percentage of recovery of CO in group IV and group II were much better than in group I(P<0.01).The LVDP,LVSP and dt/dp max showed markddly better recovery in group IV,III and II than in group I.The release of LDH was significantly increased in group I than in group II,III and IV(P<0.01).The release of CK increased markedly in group I than in group III and IV(P<0.01).Myocardial water content was significantly decreased in group II,III and IV in contrast to that of group I(P<0.01).There were significantly differences in myocardial water content between group II and group III,group II and group IV,group III and group IV.The myocardial ultrastructural changes was milder in group II,III and IV,the worst was in group I.Conclusion:Blood cardioplegia with aspartate or glutamate or both aspartate and glutamate provides better myocardial function recovery for immature myocardium,no differences in myocardial protection was shown between these two.Further studies are needed.