支链氨基酸对运动大鼠心肌能源物质代谢的影响

EFFECT OF BRANCHED CHAIN AMINO ACID SUPPLEMENTATION ON ENERGY SUBSTRATE METABOLISM IN EXERCISED RAT MYOCARDIUM

目的：探讨在运动状态下，支链氨基酸（ＢＣＡＡ）对心肌能源物质代谢的影响，为进一步研究ＢＣＡＡ对心脏功能的作用提供依据。方法：采用Ｗｉｓｔａｒ大鼠游泳运动模型，观察运动期间补充支链氨基酸（ＢＣＡＡ）对心肌中氨基酸、游离脂肪酸和糖原代谢的影响。结果：游泳运动使心肌中Ａｓｐ、Ａｌａ、Ｃｙｓ、Ｖａｌ显著增加，Ｇｌｎ、Ｇｌｕ降低，除Ａｌａ外，血浆中许多氨基酸都有不同程度的升高，其中Ｔａｕ、Ｇｌｎ、Ｃｙｓ、Ｉｌｅ、Ｐｈｅ达到了显著性；硬脂酸（Ｃ１８０）升高，花生四烯酸（Ｃ２０４）降低。心肌糖原升高，骨骼肌和肝脏糖原含量降低。补充ＢＣＡＡ后，心肌和血浆中的ＢＣＡＡ显著增加，同时心肌中Ａｓｐ、Ｇｌｎ、Ａｌａ显著高于运动对照组，血清中与糖原异生有关的氨基酸Ｇｌｎ、Ｇｌｕ、Ａｌａ显著降低；肌糖原升高；Ｃ１８０降低。结论：运动条件下，增加ＢＣＡＡ的氧化，使心肌中的一些重要的氨基酸含量增加；促进了糖原异生或节约了肌糖原，可能有利于脂肪的氧化。

Objective:This study was carried out to investigate the effect of branched chain amino acids(BCAA)supplementation on energy substrate metabolism in myocardium,and collect data about the effect of BCAA metabolism on the cardiac function for further study.Method:The effect of BCAA supplementation on amino acid,free fatty acid and glycogen metabolism in myocardium was investigated in trained Wistar rats during swimming.Results:The Asp,Ala,Cys,Val contents in myocardium were increased,the Gln,Glu contents were decreased by exercise;Meanwhile,some serum amino acids such as Tau,Gln,Cys,Ile,Phe except Ala were significantly increased.The levels of stearic acid(C 18∶0 )and glycogen were increased,while arachidonic acid(C 20∶4 )was decreased in myocardium during swimming.After BCAA supplementation,the BCAA,Asp,Gln,Ala contents in myocardium were increased.However,some glycogenic amino acids in serum,such as Gln,Glu,Ala were decreased.Both significantly higher glycogen content in myocardium and skeletal muscle and lower C 18∶0 content in myocardium were also observed.Conclusion:The data suggested that enhanced BCAA availability increased some important amino acid contents in myocardium,stimulated glycogenesis or spared glycogen,and fat oxidation could be facilitated.