负重爬梯训练对大鼠腓肠肌IGF-Ⅰ、IGF-IEa、MGF和MSTN基因表达的影响

目的:研究负重爬梯训练对大鼠腓肠肌IGF-I,IGF-I Ea,MGF和MSTN基因表达的影响。方法:12只8周龄SD雄性大鼠随机分为实验组(TG,training group)和对照组(CG,control group)。TG组采用尾部负重(负荷从体重的30%逐周增加至200%)爬梯训练模式,训练10周(3times/set,2sets/day,3days/week),采用免疫组化和RT-PCR方法分析大鼠腓肠肌IGF-I多肽、IGF-I Ea、MGF和MSTNmRNA基因表达。结果:10周训练后,相对CG组,IGF-I多肽和MGF mRNA在TG组腓肠肌的表达量上调(P<0.05),IGF-I Ea mRNA的表达量没有变化(P>0.05),MSTN mRNA的表达量下调(P<0.05)。结论:负重爬梯抗阻训练可以通过上调IGF-I多肽、MGF mRNA和下调MSTN mRNA引起大鼠腓肠肌肌肉肥大,IGF-IEa mRNA对这一过程可能没有影响。     

胰岛素样生长因子- I 对骨骼肌生长和修复研究进展

生长激素（GH）／胰岛素样生长因子-I（IGF-I）轴是肌肉生长的重要调节因子之一。虽然许多组织都能表达IGF-I，但它们各自的功能不同。骨骼肌是IGF—I的靶器官，同时也分泌IGF—I。骨骼肌组织表达的IGF—I对骨骼肌损伤后的再生、修复非常重要，也是通过适当干预保持肌肉质量的重要调节因素。主要讨论GH／IGF—I在促进骨骼肌再生和修复中的作用，并讨论其在运动康复中的应用前景。     

耐力运动对大鼠IGF-I基因表达及卫星细胞增殖的影响

采用半定量RT-PCR法和透射电镜法,观察大鼠不同运动强度游泳运动后骨骼肌IGF-IEa mRNA和MGF mRNA表达水平的变化以及骨骼肌卫星细胞的形态变化,阐述运动使骨骼肌增生肥大和损伤再修复的机制。     

胰岛素样生长因子促进骨骼肌损伤修复

胰岛素样生长因子I和II(IGF I和II)通过两种主要的细胞表面受体 (I型和II型 )和许多结合蛋白 (IGFBP)发挥生物学作用。骨骼肌不仅是IGF作用的靶细胞 ,而且也是IGF的制造者。骨骼肌损伤后再生过程中 ,IGF I或IGF II的表达水平升高。在成肌细胞增生过程中 ,IGF I的表达一直升高直至复制高峰阶段达到最高水平 ,而后下降。在整个增生过程中 ,IGF II一直呈低水平表达 ,在分化阶段升高到巅峰状态。如果外源给予IGF I,可能可以延缓肌萎缩进展 ,延缓衰老。     

衰老性肌肉丢失与机械生长因子相关研究的进展

衰老性肌肉丢失是由衰老引起肌肉质量下降和肌肉力量减弱.在机械刺激和组织损伤的情况下,机械生长因子MGF出现表达,具有增加肌肉质量的能力,另外还可能受到生长激素的影响.衰老进程中,骨骼肌MGF表达下降,激活有限的卫星细胞,不能完全修复受损细胞.而运动影响衰老骨骼肌MGF表达,进而减缓衰老性肌肉丢失的发生.     

运动对RBP4诱导的胰岛素抵抗鼠骨骼肌PTP1B表达的影响

目的研究运动对RBP4诱导的胰岛素抵抗大鼠骨骼肌PTP1B表达的影响,探讨运动影响RBP4诱导的胰岛素抵抗机制。方法 8周龄雄性SD大鼠给予重组RBP4腹腔注射,建立胰岛素抵抗鼠模型。设RBP4+运动组(RE)、RBP4+安静组(RQ)和正常安静对照组(C),RE组予3周游泳训练。ELISA、液闪计、免疫组化法、免疫印记法和RT-PCR法分别检测血清RBP4,胰岛素敏感指数QUICK I、葡萄糖摄取率和骨骼肌PTP1B、GLUT4 mRNA表达。结果 RE和RQ组血清RBP4和PTP1B表达显著高于C组,葡萄糖摄取率、QUICK I和GLUT4 mRNA表达显著低于C组;3周游泳训练后,RE组血清RBP4和骨骼肌PTP1B表达显著低于RQ组,葡萄糖摄取率、QUICK I和GLUT4 mRNA表达显著高于RQ组。结论 3周游泳运动能够显著降低RBP4诱导的胰岛素抵抗大鼠骨骼肌PTP1B表达,增加GLUT4 mRNA表达,促进葡萄糖摄取,改善胰岛素抵抗。     

Age-specific response of skeletal muscle extracellular matrix to acute resistance exercise: A pilot study

The extracellular matrix (ECM) plays an essential role in the development, growth and repair of skeletal muscles and serves to transmit contractile force. However, its regulation is poorly understood. This study investigates the age-specificity of the effects of acute resistance exercise on ECM gene expression. To this purpose, five young (YM, 23.8?±?2.2 yrs.) and 5 elderly (EM, 66.8?±?4.1 yrs.) men performed one session of unilateral leg press and leg extension exercises. Six hours post-exercise, biopsies were taken from the vastus lateralis muscles of both legs. A PCR array was used to profile the expression of 84 ECM-related genes, of which 6 were validated by qPCR. The PCR array found 9 and 4 ECM-associated genes to be selectively altered (>1.5-fold change) in YM or EM only. Four further genes were upregulated in YM but downregulated in EM. Of the 6 genes validated on individual samples MMP9 expression increased in YM (9.7-fold) and decreased (0.2-fold) in EM. MMP15 was downregulated in EM only (0.6-fold). A significant correlation between leg extension 1 RM and changes in COL7A1 expression (ρ?=?0.71) suggests a potential influence of fitness levels. In conclusion, acute resistance exercise affects ECM gene expression at least partly in an age-specific manner. The altered expression of genes encoding matrix metalloproteinases (MMP3, MMP9, MMP15) highlights the role of remodelling processes in the response to an acute bout of resistance exercise. Larger studies are required to verify the age-associated differences in gene expression profiles and establish their functional implications.     

IGFs对骨骼肌的作用及运动对其影响

对胰岛素样生长因子系统(IGFs,主要是IGF-I)在骨骼肌的生长发育、适应性肥大、微损伤修复过程中起的作用及运动对其影响进行了综述。分析表明:IGF-I不仅可以通过与特异性IGF受体结合,来调节骨骼肌的生长发育;还可以通过局部调节蛋白质的代谢、刺激卫星细胞的增殖等方式来影响骨骼肌的生长发育、促进微损伤修复。至于运动对血清IGF-I影响的结论还不一致,但比较肯定的是运动可以提高局部组织的IGF-I水平。     

机械生长因子(MGF)与运动

机械生长因子MGF（Mechano Growth Factor）起源于胰岛素生长因子1（IGF-1），是IGF-1基因经过不同剪切而衍生的。MGF的表达主要受机械刺激和组织损伤的影响，且比肝型IGF-1具有潜在的增加肌肉质量的能力。为更好认识MGF在肌肉生长中的作用，对MGF的生物学作用，以及运动、激素对MGF的影响进行综述。     

The acute angiogenic signalling response to low-load resistance exercise with blood flow restriction

This study investigated protein kinase activation and gene expression of angiogenic factors in response to low-load resistance exercise with or without blood flow restriction (BFR). In a repeated measures cross-over design, six males performed four sets of bilateral knee extension exercise at 20% 1RM (reps per set?=?30:15:15:continued to fatigue) with BFR (110?mmHg) and without (CON). Muscle biopsies were obtained from the vastus lateralis before, 2 and 4?h post-exercise. mRNA expression was determined using real-time RT–PCR. Protein phosphorylation/expression was determined using Western blot. p38MAPK phosphorylation was greater (p?=?0.05) at 2?h following BFR (1.3?±?0.8) compared to CON (0.4?±?0.3). AMPK phosphorylation remained unchanged. PGC-1α mRNA expression increased at 2?h (5.9?±?1.3 vs. 2.1?±?0.8; p?=?0.03) and 4?h (3.2?±?0.8 vs. 1.5?±?0.4; p?=?0.03) following BFR exercise with no change in CON. PGC-1α protein expression did not change following either exercise. BFR exercise enhanced mRNA expression of vascular endothelial growth factor (VEGF) at 2?h (5.2?±?2.8 vs 1.7?±?1.1; p?=?.02) and 4?h (6.8?±?4.9 vs. 2.5?±?2.7; p?=?.01) compared to CON. mRNA expression of VEGF-R2 and hypoxia-inducible factor 1α increased following BFR exercise but only eNOS were enhanced relative to CON. Matrix metalloproteinase-9 mRNA expression was not altered in response to either exercise. Acute low-load resistance exercise with BFR provides a targeted angiogenic response potentially mediated through enhanced ischaemic and shear stress stimuli.     

运动对大鼠骨骼肌形态和代谢机能的影响

以大鼠为实验对象, 观察研究运动训练对大鼠骨骼肌形态及代谢机能的影响。16只健康、成年SD大鼠随机分为2组, 安静组 (n=8), 运动组 (n=8)。运动方案为跑台训练, 持续 8 周。研究发现, 运动组骨骼肌形态无异常变化, 肌纤维横截面积稍减小, 变化不显著。运动训练后, 骨骼肌及血清 IGF-I水平明显升高。此外,运动组琥珀酸脱氢酶活性有所下降, 而腓肠肌ATP酶活性明显升高。结论　 (1) 运动训练有效调解了体内的蛋白质代谢平衡。(2) 运动训练可以改变骨骼肌及血清IGF-I水平, 并对其蛋白质代谢产生一定的作用。(3) 运动训练在一定程度上改变了骨骼肌代谢酶活性, 从而影响其代谢功能, 以满足不同类型运动的需要。     

The improvement in walking speed induced by resistance training is associated with increased muscular strength but not skeletal muscle mass in older women

Objective: The purpose of the present study was to analyze whether improvements in fast walking speed induced by resistance training (RT) are associated with changes in body composition, muscle quality, and muscular strength in older women. Methods: Twenty-three healthy older women (69.6?±?6.4 years, 64.95?±?12.9?kg, 1.55?±?0.07?m, 27.06?±?4.6?kg/m²) performed a RT program for 8 weeks consisting of 8 exercises for the whole body, 3 sets of 10–15 repetitions maximum, 3 times a week. Anthropometric, body composition (fat-free mass [FFM], skeletal muscle mass [SMM], legs lean soft tissue [LLST], fat mass), knee extension muscular strength (KE1RM), muscle quality index (MQI [KE1RM/LLST]), and 10-meter walking test (10-MWT) were performed before and after the intervention. Results: Significant (P?<?.05) changes were observed from pre- to post-training for FFM (+1.6%), MQI (+7.2%), SMM (+2.4%), LLST (+1.8%), KE1RM (+8.6%), fat mass (?1.4%), and time to perform 10-MWT (?3.7%). The percentage change in 10-MWT was significantly associated with percentage change in MQI (r?=??0.46, P?=?.04) and KE1RM (r?=??0.45, P?=?.04), however not associated percentage of changes in SMM (r?=?0.01, P?=?.97), LLST (r?=??0.22, P?=?.33), and body fat (r?=?0.10, P?=?.66). Conclusion: We conclude that the improvement in the 10-MWT after an 8-week RT program is associated with increases in lower limb muscular strength and muscle quality, but not with muscle mass or body fat changes in older women.     

跑台运动对大鼠骨骼肌mTOR mRNA 和蛋白表达的影响

目的:mTOR信号调控骨骼肌蛋白翻译过程,本研究旨在探讨耐力运动对骨骼肌mTOR蛋白表达的影响.方法:SD大鼠分为运动组和对照组.运动组大鼠进行跑台坡度5°,上坡跑,速度20m/min,60min/次的跑台运动后12 h,采用RT-PCR方法测定腓肠肌mTOR mRNA,westerm blot测定mTOR蛋白的表达.结果:1次急性运动后大鼠骨骼肌mTOR mRNA和蛋白表达显著上升(P<0.05),4周持续耐力运动后大鼠骨骼肌mTOR mRNA和蛋白表达显著上升(P<0.05).结论:耐力运动后骨骼肌mTOR表达上升,提示mTOR可能参与肌肉生长对运动适应的调控.     

6周递增负荷训练对大鼠骨骼肌IGF-I及血清GH、IGF-I水平影响的研究

生长激素(GH)、胰岛素样生长因子I(IGF-I)都是了解GH-IGF轴变化的主要指标.IGF不仅是内分泌因子,还能在组织局部起作用.通过对6周递增负荷跑台练习的大鼠进行研究,结果显示:运动后即刻,大鼠血清GH水平明显升高(P＜0.01);运动组与对照组相比,骨骼肌IGF-I水平有明显升高(P＜0.01),表明运动对骨骼肌组织内IGF的分泌有调节作用.     

Aerobic training but no resistance training increases SIRT3 in skeletal muscle of sedentary obese male adolescents

In recent years, prevalence of obesity in children and adolescents has increased. A strategy for prevention and management of obesity is aerobic training (AT) due to its effectiveness to decrease fat mass. AT increases the content of SIRT3, a mitochondrial protein that increases the expression of PGC-1α and NFR1, thereby enhances mitochondrial function and metabolic health. Resistance training (RT) provides metabolic benefits but its effect on SIRT3 content is unknown. To compare the effect of AT and RT on SIRT3, PGC-1α and NRF-1 protein levels in skeletal muscle of sedentary obese adolescents. Twenty-seven sedentary obese male adolescents (age: 16.7?±?0.9 years; BMI: 33.7?±?4.3?kg/m²) completed a 1-month control period prior to randomization to one of two supervised exercise protocols: AT (3 days/week, 40 min/day, 70–80% peak heart rate) or RT (3 days/week, 11 exercises, 2 sets/exercise, 12 repetitions/set) for 12 weeks. Biopsies were obtained from the vastus lateralis muscle before and after 12 weeks to analyse SIRT3, PGC-1α and NRF-1 proteins content. Peak oxygen consumption (VO_2peak) and anthropometric variables were evaluated before and after training. AT increased SIRT3 content, which was associated with improvements in PGC-1α content and body fat percentage. RT did not affect SIRT3 or PGC-1α. VO_2peak increased only in AT. The increase in muscle mitochondrial SIRT3 was observed only following AT. In contrast, RT increased muscle mass without improving SIRT3 in obese male adolescents.     

肌球蛋白重链可塑性和机械负荷状态对其影响

肌球蛋白重链(Mysion Heavy Chain,MHC)是横纹肌收缩蛋白的重要组成成分。已发现MHC有多种亚型，在不同的机械负荷下可相互转化，呈现出对外界机械信号的高度适应性。机械生长因子(Mechano Growth Factor，MGF)可能在机械负荷和MHC亚型转变间发挥化学桥梁的功能。     

Oral conjugated linoleic acid supplementation enhanced glycogen resynthesis in exercised human skeletal muscle

Present study examined the effects of conjugated linoleic acid (CLA) supplementation on glycogen resynthesis in exercised human skeletal muscle. Twelve male participants completed a cross-over trial with CLA (3.8 g/day for 8 week) or placebo supplements by separation of 8 weeks. CLA is a mixture of trans-10 cis-12 and cis-9 trans-11 isomers (50:50). On experiment day, all participants performed 60-min cycling exercise at 75% VO₂ max, then consumed a carbohydrate meal immediately after exercise and recovered for 3 h. Biopsied muscle samples from vastus lateralis were obtained immediately (0 h) and 3 h following exercise. Simultaneously, blood and gaseous samples were collected for every 30 min during 3-h recovery. Results showed significantly increased muscle glycogen content with CLA after a single bout of exercise (P < 0.05). Muscle glucose transporter type 4 expression was significantly elevated immediately after exercise, and this elevation was continued until 3 h after exercise in CLA trial. However, P-Akt/Akt ratio was not significantly altered, while glucose tolerance was impaired with CLA. Gaseous exchange data showed no beneficial effect of CLA on fat oxidation, instead lower non-esterified fatty acid and glycerol levels were found at 0 h. Our findings conclude that CLA supplementation can enhance the glycogen resynthesis rate in exercised human skeletal muscle.     

Effect of 8 weeks of concurrent plyometric and running training on spatiotemporal and physiological variables of novice runners

Concurrent plyometric and running training has the potential to improve running economy (RE) and performance through increasing muscle strength and power, but the possible effect on spatiotemporal parameters of running has not been studied yet. The aim of this study was to compare the effect of 8 weeks of concurrent plyometric and running training on spatiotemporal parameters and physiological variables of novice runners. Twenty-five male participants were randomly assigned into two training groups; running group (RG) (n?=?11) and running + plyometric group (RPG) (n?=?14). Both groups performed 8 weeks of running training programme, and only the RPG performed a concurrent plyometric training programme (two sessions per week). Anthropometric, physiological (VO_2max, heart rate and RE) and spatiotemporal variables (contact and flight times, step rate and length) were registered before and after the intervention. In comparison to RG, the RPG reduced step rate and increased flight times at the same running speeds (P?P?P?2max increased more in the RPG than in the RG. In conclusion, concurrent plyometric and running training entails a reduction in step rate, as well as increases in VT speed, RCT speed, peak speed and VO_2max. Athletes could benefit from plyometric training in order to improve their strength, which would contribute to them attaining higher running speeds.     

Improvement of cellular health indicators and muscle quality in older women with different resistance training volumes

ABSTRACT

The main purpose of this study was to compare the effects of resistance training (RT) performed with different training volumes on phase angle (PhA), body water components, and muscle quality (MQ) in untrained older adult women. A second purpose was to assess the relationship between PhA and MQ. Sixty-two older adult women (68.6 ± 5.0 years, 65.2 ± 13.3 kg, 156.1 ± 6.2 cm) were randomly assigned into one of the three groups: two training groups performed either 1 set (G1S) or 3 sets (G3S), or a control group (CG). Body water components and PhA were estimated by bioelectrical impedance (BIA). MQ was determined by dividing skeletal muscle mass estimated by dual-energy absorptiometry (DXA) by total muscle strength from three exercises. After the intervention period, both training groups demonstrated improvements (P < 0.05) when compared with CON for intracellular water, total body water, PhA, and MQ. These results suggest that RT can improve PhA, body water components, and MQ after 12 weeks of RT in untrained older women, regardless of training volume. Furthermore, changes in MQ were positively correlated with changes in PhA (r = 0.60, P < 0.01).