支链氨基酸提高大鼠游泳耐力作用探讨

目的 :　探讨支链氨基酸 (BCAA)对提高大鼠运动耐力的作用。方法 :　取雄性Wistar大鼠 2 1只 ,随机分为三组 :正常组、游泳对照组及游泳补充 5% BCAA饲料组。两个游泳组每天游泳训练 1 h,1 0 d后 ,游泳 6h,观察游泳大鼠的存活率 ,测定血乳酸和尿素氮水平 ,血清和骨骼肌乳酸脱氢酶 (LDH)活力 ,线粒体脂质过氧化物 (LPO)水平和线粒体膜的粘度系数。另取昆明种小鼠 ,随机分为三组 ,用实验一相同的饲料喂养 ,两周后 ,于每只小鼠尾静脉注射 15N-甘氨酸 (15N-Gly) 1 .0 mg,注射后 和 组立即游泳 ,分别于注射后的 1、2、3及 4h,测定各组骨骼肌蛋白质中15N-甘氨酸 (15N- Gly)的丰度。结果 :　BCAA可明显提高大鼠游泳存活率 ,抑制游泳运动后大鼠的血乳酸浓度、LDH活力、骨骼肌 LPO的升高幅度 ,抑制骨骼肌 LDH活力和膜流动性下降的趋势。并且 BCAA还可增加 15N- Gly在骨骼肌蛋白质中的滞留时间。结论 :　BCAA可改善运动后骨骼肌线粒体功能 ,改善运动性疲劳 ,提高大鼠的运动耐力

EFFECT OF BRANCHED-CHAIN AMINO ACIDS ON EXERCISE CAPABILITY IN SWIMMING RATS

Objective:The effect of branched chain amino acids (BCAA) on exercise capability were investigated. [WT5HZ]Methods In experiment Ⅰ, 21 male Wistar rats were randomly divided into three groups: control group, swimming training group and swimming training+BCAA group in which the rats were fed with fodder containing BCAA supplement. The rats in the two swimming training groups were forced to swim for one hour everyday. After ten days training, the rats were forced to swim for 6 hrs. The survival rate of rats, the contents of lactic acid in serum, blood urea nitrogen (BUN), and the activity of lactate dehydrogenase (LDH) in serum and skeletal muscle, and the mitochondrial level of lipid peroxidation and membrane fluidity in skeletal muscle were observed. In experiment Ⅱ, 75 mice were randomly divided into three groups and fed the same diet as expeiment Ⅰ. After two weeks, the mice were administered 1.0 mg 15 N Gly and forced to swim. The percentage of 15 N Gly in skeletal muscle protein were determined at 1,2,3,4 h after administration respectivley. [WT5HZ]Results: [WT5BZ]It was found that BCAA increased survival rate in swimming rats, decreased serum lactic acid and LDH activity, decreased the mitochondrial LPO in skeletal muscle after swimming, and increased LDH activity and the mitochondrial membrane fluidity in skeletal muscle. BCAA also increased the retention time of 15 N Gly in skeletal muscle protein in mice. [WT5HZ]Conclusion:[WT5BZ] BCAA can improve mitochondrial function in skeletal muscle and prevent the onset of fatigue and increase exercise capability.