补充小麦肽对模拟高原训练大鼠骨骼肌蛋白质的影响及IGF-1的调节作用

目的:探讨补充小麦肽对模拟高原训练大鼠骨骼肌蛋白质代谢的影响及其机制。方法:雄性SD大鼠60只随机分成正常对照组(C组,n=10)、低氧对照组(HC组,n=10)、运动训练组(E组,n=10)、运动训练+小麦肽补充组(EW组,n=10)、低氧+运动训练组(HE组,n=10)和低氧+运动训练+小麦肽组(HEW组,n=10)6组。低氧条件为模拟海拔3000 m,氧浓度为14.2%。运动训练采用90min无负重游泳,每周6天。EW组和HEW组每次训练后按照500 mg/kg体重剂量灌服小麦肽溶液。9周后检测各组大鼠血清IGF-1含量及骨骼肌总蛋白(Pro)、肌球蛋白(Myo)和胰岛素样生长因子-1(IGF-1)含量。结果:①与C组相比,HC组大鼠骨骼肌Pro和Myo含量显著降低(P<0.01);同时,HC组大鼠血清和骨骼肌IGF-1含量均显著下降(P<0.05)。②与C组相比,E组大鼠骨骼肌Pro含量无显著性差异(P>0.05),Myo含量显著降低(P<0.05),血清和骨骼肌IGF-1含量均显著下降(P<0.05)。③通过双因素方差分析,长期模拟高原训练显著降低大鼠骨骼肌Pro和Myo含量(P=0.05),虽可降低大鼠血清和骨骼肌IGF-1含量,但差异无统计学意义(P>0.05)。④双因素方差分析发现,补充小麦肽显著提高运动训练大鼠骨骼肌Pro和Myo水平(P<0.01),也显著提高运动训练大鼠血清和骨骼肌IGF-1含量(P<0.05,P<0.01)。⑤双因素方差分析发现,低氧和补充小麦肽对提高大负荷训练大鼠骨骼肌Pro、IGF-1及血清IGF-1含量有显著性交互作用(P<0.05),但对提高大负荷训练大鼠骨骼肌Myo含量无显著性交互作用(P>0.05)。结论:①长期低氧暴露或高原训练抑制IGF-1分泌,抑制骨骼肌蛋白质合成。②补充小麦肽有效促进大负荷运动训练或高原训练大鼠IGF-1分泌,对减缓大负荷运动训练或高原训练引起的大鼠骨骼肌蛋白质含量降低有重要作用。

Supplementation of Wheat Peptides Increases Skeletal Muscle Protein level of Rats during Simulated Altitude Training

Objective To explore the effect of wheat peptide supplementation on skeletal muscle protein metabolism in rats during altitude training.Methods 60 SD rats were randomly divided into normal control group(C,n = 10),hypoxic exposure control group(HC,n = 10),exercise group(E,n = 10),exercise + wheat peptides supplementation group(EW,n = 10),hypoxic exposure + exercise group(HE,n = 10) and exposure + exercise + wheat peptide supplementation group(HEW,n = 10).Hypoxic condition was simulated at altitude of 3000m with oxygen concentration of 14.2%.90-minute unload swimming was used for rats in exercise groups,6 days a week.Intragastric administration of wheat peptide solution was applied to the rats in groups EW and HEW after each training session with the dose of 500 mg/kg·BW.After 9 weeks of experiment,serum insulin growth factor-l(IGF-1),skeletal muscle protein(Pro) and myosin(Myo) were measured.Results ① Compared with group C,skeletal muscle Pro and Myo contents reduced significantly(P < 0.01),and IGF-1 content of serum and skeletal muscle decreased significantly(P < 0.05) in group HC.② Compared with group C,skeletal muscle Pro changed insignificantly(P > 0.05),Myo content reduced significantly(P < 0.05),and IGF-1 content of serum and skeletal muscle decreased significantly in group E(P< 0.05).③ Skeletal muscle Pro and Myo contents increased significantly(P < 0.01),and IGF-1 content of serum and skeletal muscle increased significantly(P < 0.05 and P < 0.01,respectively) in group EW.④ Muscle Pro and IGF-1,and serum IGF-1 increased significantly in group HEW(P < 0.05) with insignificant change in muscle Myo content(P > 0.05).Conclusions ① Long-term hypoxic exposure or altitude training could inhibit the synthesis of skeletal muscle protein through restraining the IGF-1 secretion.② Supplementation of wheat peptides could effectively improve the secretion of IGF-1 in rats during altitude training,and slow down the decrease in skeletal muscle protein induced by altitude training.