亮氨酸对增龄小鼠腓肠肌蛋白质合成的影响  

Effect of Dietary Leucine Supplementation on Protein Synthesis of Gastrocnemius Muscle in Aging Mice

作　　者：夏志[1] 赵艳[2] 尚画雨 叶菊菲 杨力源[4] 熊伟平[5] 苏全生[4] 

机构地区：[1]井冈山大学体育学院,江西吉安343009 [2]武汉体育学院研究生院,湖北武汉430079 [3]北京体育大学,北京100084 [4]成都体育学院,成都610041 [5]保山学院体育学院,云南保山678000

出　　处：《北京体育大学学报》2014年第11期79-85,共7页Journal of Beijing Sport University

基　　金：江西省科技厅自然科学基金青年科学基金项目(No.20142BAB215048);江西省教育厅科学技术研究一般项目(No.GJJ13550)

摘　　要：目的:观察膳食补充亮氨酸对增龄小鼠骨骼肌蛋白质合成的影响并初步探讨其可能性机制。方法:13月龄雄性ICR小鼠据体重随机分为补充亮氨酸、补充丙氨酸以及空白对照组,补充亮氨酸和补充丙氨酸组分别在饲料中给予亮氨酸(5%)和丙氨酸(3.4%)添加8周,空白对照组则进食普通维持饲料。末次给食后禁食17 h并处死小鼠,用血糖仪检测血糖;ELISA检测血清胰岛素;HE染色观察腓肠白肌肌纤维适应性变化;Western blotting检测PI3K III(m VPS34)与MHCⅡ蛋白表达及m TOR、p70S6K、4E-BP1磷酸化率。结果:添加亮氨酸并未显著影响小鼠体重与采食量,且未致胰岛素与血糖水平变化不显著。腓肠白肌湿重、湿重/体重比值、肌纤维横截面积与直径表现出增大的趋势,但变化并不显著。但肌肉蛋白总量、m VPS34与MHCⅡ的蛋白表达及m TOR、p70S6K、4E-BP1磷酸化率均显著增加。结论:5%比例亮氨酸具有促进骨骼肌蛋白质合成并减缓老年前期小鼠肌肉的萎缩的潜力,其机制可能涉及肌细胞内PI3K III(m VPS34)/m TOR/p70S6K信号通路的活化。Objective: This study investigated the effect of leucine supplementation on protein synthesis of skeletal muscles in aging mice and detected its possible mechanism. Methods: Thirteen-month-old male ICR mice were randomly divided into dietary leucine supplementation,alanine supplementation and normal control groups according to body weight. Mice in leucine and alanine supplementation groups were fed with normal chow diet supplemented with 5% leucine and 3. 4% alanine respectively for 8 weeks,while normal control group were fed with normal diet. Mice were killed 17 h after the last feeding. Blood glucose was measured by a blood glucose meter,serum insulin concentration was tested by ELISA,skeletal muscle morphology was observed after HE staining,protein expression of PI3 K III( m VPS34) and MHC Ⅱ as well as the phosphorylation rate of m TOR,p70S6 K and4E-BP1 were detected by Western blotting. Results: Leucine supplementation did not change body weight,food intake,blood glucose,and serum insulin level. The wet weight of white gastrocnemius muscle,ratio of wet white gastrocnemius muscle and body weight,cross-sectional area and diameter of fibers showed a tendency to increase after leucine supplementation,but all are not significant. Total protein content,the protein expression of PI3 K Ⅲ and MHC Ⅱ,the phosphorylation rate of mTOR,p70S6 K and 4E-BP1 in white gastrocnemius muscle were significantly increased after leucine supplementation. Conclusion: Leucine supplementation can promote protein synthesis and attenuate muscle atrophy in pre-senile mice, and its mechanism refers to activation of PI3 K Ⅲ( mVPS34) / mTOR/ p70S6 K signal pathway.

关 键 词：亮氨酸 蛋白质合成 肌肉萎缩 Ⅲ型磷脂酰肌醇(-3)激酶 哺乳动物雷帕霉素靶蛋白 

分 类 号：G804.2[文化科学—运动人体科学]