MSTN基因的研究进展

肌肉生长抑制素(MSTN)又称GDF-8,属TGF-β超家族,是1997年发现的一种骨骼肌生长发育的负调控因子。其活性的丧失或降低,会引起动物肌肉的过度发育,表现为双肌性状。本文综述了MSTN基因的发现、同源性分析、特点、作用机制及其在常见家畜的研究进展及应用前景。     

TGF-β/肌肉生长抑制素信号通路对骨骼肌作用的研究进展

转化生长因子β(TGF-β)及其超家族成员肌肉生长抑制素(myostatin,MSTN)在哺乳动物骨骼肌的胚胎期及生长发育过程中发挥着重要的作用.本文综述了TGF-β/myostatin信号通路在骨骼肌中的作用尤其是在骨骼肌生长发育、生理学和病理学中作用的最新研究进展,并展望了该信号通路在骨骼肌发育和疾病等方面的应用前...     

力竭运动及恢复期间大鼠骨骼肌及心肌MSTN、TGF-β、PDGF含量的变化

目的:研究力竭运动及恢复期间大鼠骨骼肌及心肌肌肉生长抑制素(MSTN)、转化生长因子β(TGF-β)和血小板生长因子(PDGF)的变化。方法:Wistar雄性大鼠24只,随机分为4组,每组6只。E0组、E24组、E48组均进行一次性跑台力竭运动,并分别于力竭即刻、24小时后、48小时后处死;对照组(C组)不进行运动干预,随运动组后处死。取心肌与左侧腓肠肌,ELISA检测组织中MSTN、TGF-β和PDGF。结果:一次力竭运动后,与C组相比,E0组、E24组、E48组骨骼肌和心肌中MSTN、TGF-β的含量均显著性下降(P<0.05,P<0.01),PDGF含量则显著性升高(P<0.01);E0、E24、E48组间无显著性差异。结论:MSTN、TGF-β可能在骨骼肌、心肌修复及肌卫星细胞激活中起负调节作用,PDGF可能在骨骼肌、心肌修复中起正调节作用。     

siRNA真核表达载体构建及对细胞MSTN基因抑制的研究

肌肉生长抑制素是肌肉生长的负调控因子。本研究为了得到有效抑制绵羊MSTN基因的siRNA分子,设计8对siRNA寡聚核苷酸引物,经退火与pSilencerTM4.1-CMV neo连接构建siRNA真核表达载体,转染C2C12细胞后,利用RT-PCR及real time PCR检测干扰效果。结果显示,8条siRNA分子中有3条对MSTN基因有显著的抑制作用,其中psi-mstn-717和psi-mstn-986分子对MSTN mRNA抑制效率分别达到61%和53%。本研究证实载体表达siRNA能有效抑制细胞MSTN mRNA的表达,下一步筛选的siRNA将用于体内实验。     

运动性心肌肥大大鼠心肌肌肉生长抑制素表达的变化

目的:观察运动性心肌肥大大鼠心肌组织肌肉生长抑制素(myostatin,MSTN)表达的变化。方法:16周龄雄性SD大鼠随机分为对照组和运动组,每组10只。运动组进行持续8周跑台训练,每周5次,每次60分钟,跑速26米/分钟。测定两组大鼠心重并计算心系数,HE染色观察心肌细胞横截面积,分别采用real-time PCR技术和western blot方法测定心肌MSTN mRNA和蛋白表达,放免法测定血浆MSTN水平。结果:运动组大鼠心脏重量和心系数显著高于对照组(P<0.05),心肌细胞横截面积增大。运动组大鼠血浆MSTN水平、心肌MSTN mRNA和蛋白表达显著低于对照组(P<0.05)。结论:运动性心肌肥大时,大鼠心肌MSTN mRNA和蛋白表达被抑制,可能通过解除其对心肌生长的负调控作用,促进心肌细胞对运动产生适应性肥大。     

骨骼肌的内分泌功能与运动代谢适应

运动适应惠及机体多个系统和器官,运动器官骨骼肌在运动代谢适应中的作用日益突出,这个传统上神经和体液调控的效应器官近些年来其内分泌功能备受关注。骨骼肌能合成、分泌调节肽、生长因子等多种生物活性分子。这些生物活性分子统称为"肌肉因子"(myokine),其中,部分以旁分泌方式调控骨骼肌生长发育和糖、脂代谢,如肌肉抑制素(myostatin)、白细胞介素6(IL-6)、IL-15和脑源性神经营养因子(BDNF)等;部分还能以激素方式发挥内分泌功能,如肌脂素(myonectin),成纤维细胞生长因子21(FGF-21)和PGC-1α依赖性肌肉因子鸢尾素(Irisin)、β羟基异丁酸(BAIBA),成为介导骨骼肌与肝脏、脂肪、脑等器官或组织之间的"cross-talk"的重要信使分子。运动是促进代谢适应,防治缺乏运动引起的多种慢性代谢病,如肥胖、胰岛素抵抗、慢性炎症、2型糖尿病(T2DM)的有效手段,肌肉因子的发现为运动防控慢性病机制提供了崭新的视角,因为绝大部分肌肉因子的合成和分泌依赖于骨骼肌收缩。     

基本空战动作“检查6点钟”姿势腰背训练方案的表面肌电图特征研究

目的针对飞行员基本空战"检查6点钟"动作设计体能训练方法并进行评价,探讨改进飞行员体能训练的方法。方法针对"检查6点钟"动作设计左右方向腰背肌肉训练方法,8名受试者每周3次力量训练,并配合HP动作,训练周期为3个月。训练前对受试者进行力量素质、HP呼吸配合情况及负荷下肌肉运动表面肌电基线指标的测量,腰背肌肉表面肌电测量选取左右冈下肌、左右背阔肌及左右竖脊肌,训练效果指标为训练前后"检查6点钟"动作腰背肌肉力量及表面肌电值。结果训练后腰背肌肉力量显著增加(P0.001)。表面肌电图(sEMG)显示训练后拉力增加,肌肉等长收缩时积分肌电值(iEMG)显著增加(P0.05),等张运动时除左侧冈下肌iEMG增加(P0.05)外,其余iEMG呈下降趋势,两种运动方式均以背阔肌和冈下肌变化最为显著。训练后肌肉在同样iEMG值时力量输出更大。疲劳分析结果显示,除右背阔肌(左上旋时)和右竖脊肌(右上旋时)中值频率(MF)值略有降低(P0.05),其余肌肉MF值无明显降低,频率曲线无明显左移,双侧冈下肌频率曲线反而右移,MF值增加(P0.05),结果表明肌肉抗疲劳能力增加。此外,训练后深层冈下肌肌肉贡献率较训练前增加,竖脊肌和背阔肌放电则降低或变化不大。结论专项设计方案训练效果显著,训练后受试者腰背肌肉力量显著增加,抗疲劳能力增加,深层小肌肉激发,脊柱运动更加稳定,对飞行员腰背保护更加有力。     

地塞米松对小鼠体成分的影响

 目的 探讨地塞米松对两种不同年龄小鼠体成分的影响,筛选出较为理想的肌肉衰减综合征模型。方法 C57BL/6雄性小鼠,8~10周龄随机分为2组,对照组(NA)和实验组(DA),6~7月龄随机分为2组,对照组(NM)和实验组(DM)。每组8只,对照组注射生理盐水,实验组注射5 mg/kg 地塞米松,皮下注射19 d。每3 d测量小鼠体成分,最后一次给药24 h后,利用Echo MRITM检测小鼠体成分。结果 干预后,DA组与NA组相比,体重降低5.97%(P<0.05),肌肉量降低14.33%(P<0.01),脂肪量增加32.94%(P<0.05)。DM组和NM组相比,体重增加13.67%(P<0.05),肌肉量降低6.06%(P<0.05),脂肪量增加43.77%(P<0.01)。6~7月龄和8~10周龄小鼠相比,地塞米松对肌肉的干预效果无统计学差异(P=0.148),地塞米松对脂肪的干预效果具有统计学差异(P<0.05),6~7月龄小鼠脂肪的增加高于8~10周龄小鼠。结论 本实验的干预条件下,6~7月龄小鼠较8~10周龄小鼠更适于做长期研究的肌肉衰减综合征模型。     

脂联素对肝星状细胞抗肝纤维化及抑制细胞增殖的机制研究

目的 检测脂联素对肝星状细胞HSC-T6的抗纤维化作用,以及一氧化氮(NO)在其中的作用.方法 将HSC-T6细胞分为对照组、脂联素组(终浓度5μg/ml)、脂联素+L-NAME组(脂联素终浓度5μg/ml,L-NAME终浓度5mmol/L),分别于治疗24h后收集HSC-T6细胞,提取RNA和蛋白质行基因和蛋白表达的检测.另外,为检测脂联素与不同浓度L-NAME共同作用下iNOS基因的表达情况,将脂联素+L-NAME组根据L-NAME的浓度分为0.25、0.5、1.0、2.5、5.0和10.0mmol/L亚组,以上各组中脂联素均为5μg/ml.采用实时荧光定量PCR检测HSC内诱导型一氧化氮合成酶(iNOS)、α-平滑肌肌动蛋白(α-SMA)、I型胶原蛋白(chollagen I)和转化生长因子-β(TGF-β)基因的表达;western blotting法检测iNOS蛋白的表达;采用ELISA法检测HSC-T6培养基中NO代谢产物(硝酸盐、亚硝酸盐)的浓度;采用BrdU法检测HSC-T6细胞的增殖情况.结果 与对照组比较,脂联素作用下HSC-T6细胞内iNOS基因的表达显著升高(P<0.01),α-SMA、Chollagen I、TGF-β等基因的表达均显著下调(P<0.01),iNOS蛋白表达水平显著上调(P<0.05),细胞培养基中硝酸盐、亚硝酸盐的水平显著升高(P<0.05),细胞增殖显著受抑(P<0.01),上述对细胞增殖的抑制作用在NOS抑制剂L-NAME的作用下发生逆转.结论 脂联素可下调HSC-T6细胞内纤维化指标的表达,抑制细胞增殖,这种作用至少部分由NO介导.     

两种肌肉调理方法对新学员5km越野后肌疲劳干预效果的比较

 目的 观察本体感觉神经肌肉促进法(proprioceptive neuromuscular facilitation,PNF)与心理肌肉放松法对新学员5 km越野训练肌疲劳的影响,以得出最佳运动后疲劳的恢复方式.方法 选择南京某院校2006-09入学的144名新学员作为研究对象,随机分为A组(PNF干预组)、B组(心理肌肉放松干预组)和C组(对照组),在训练前、训练后第3天、第5天分别评定肌疲劳度并行相关血液生化指标检查.结果 PNF干预组训练后第3天、第5天的肌疲劳程度及血液生化指标增幅较心理肌肉放松干预组及对照组低,心理肌肉放松干预组训练后第3天、第5天的肌疲劳程度及血液生化指标增幅仅较对照组低.3组新学员肌疲劳变化程度差异和相关血液生化指标平均增幅差异均有统计学意义(P<0.05),其中PNF干预组<心理肌肉放松干预组<对照组.结论 PNF法与心理肌肉放松训练法均能有效降低参训人员运动后疲劳,其中PNF法作用更显著.     

Knee injury and Osteoarthritis Outcome Score (KOOS) - validation of a Swedish version

The Knee injury and Osteoarthritis Outcome Score (KOOS) is a self-administered instrument measuring outcome after knee injury at impairment, disability, and handicap level in five subscales. Reliability, validity, and responsiveness of a Swedish version was assessed in 142 patients who underwent arthroscopy because of injury to the menisci, anterior cruciate ligament, or cartilage of the knee. The clinimetric properties were found to be good and comparable to the American version of the KOOS. Comparison to the Short Form-36 and the Lysholm knee scoring scale revealed expected correlations and construct validity. Item by item, symptoms and functional limitations were compared between diagnostic groups. High responsiveness was found three months after arthroscopic partial meniscectomy for all subscales but Activities of Daily Living.     

Endovascular management of carotid-cavernous fistulas

Objective To investigate endovascular treatment of traumatic direct carotid-cavernous fistulas （CCF） and their complications such as pseudoaneurysms. Methods： Over a five-year period, 22 patients with traumatic direct CCFs were treated endovascularly in our institution. Thirteen patients were treated once with the result of CCF occluded, 8 twice and 1 three times. Treatment modalities included balloon occlusion of the CCF, sacrifice of the ipsilateral internal carotid artery with detachable balloon, coll embolization of the cavernous sinus and secondary pseudoaneurysms, and covered-stem management of the pseudoaneurysms. Results All the direct CCFs were successfully managed endovascularly. Four patients developed a pseudoaneurysm after the occlusion of the CCF with an incidence of pseudoaneurysm formation of 18.2% （4/22）. A total number of 8 patients experienced permanent occlusion of the ICA with a rate of ICA occlusion reaching 36.4% （8/22）. Followed up through telephone consultation from 6 months to 5 years, all did well with no recurrence of CCF symptoms and signs. Conclusion Traumatic direct CCFs can be successfully managed with endovascular means. The pseudoaneurysms secondary to the occlusion of the CCFs can be occluded with stent-assisted coiling and implantation of covered stents.     

The acutely limping child

Acute limping may be the result of multiple pathologies in children. The differential diagnosis varies based on the age of the child. Irrespective of age, the initial imaging work-up includes AP and frog leg radiographs of the pelvis and ultrasound; MRI may sometimes be helpful. In children less than 3 years, infections and trauma are most frequent. MRI is the imaging modality of choice when osteomyelitis is clinically suspected. Between the ages of 3 and 10 years, transient synovitis of the hip and Legg-Calvé-Perthes disease are main considerations but infection, inflammation and focal bony lesions are also considered. In children over 10 years, slipped capital femoral epiphysis also is considered.     

Do Balance Board Training Programs Reduce the Risk of Ankle Sprains in Athletes?

Introduction Ankle sprains are the most common musculo-skeletal injury that occurs in athletes,particularly in sports that require jumping and landing on one foot such as soccer,and basketball(1-4).These injuries often result in significant time loss from participation,long-term disability,and have a major impact on health care costs and resources(5-8).     

High Intensity Interval Training:New Insights

KEY POINTS ·High-intensity interval training(HIT)is characterized by repeated sessions of relatively brief，intermittent exercise.often performed with an“a11 out”effort or at an intensity close to that which elicits peak oxygen uptake(i.e.，≥90%of VO2 peak).     

Developmental validation of the PowerPlex(®) ESI 16 and PowerPlex(®) ESI 17 Systems: STR multiplexes for the new European standard

In response to the ENFSI and EDNAP groups’ call for new STR multiplexes for Europe, Promega^® developed a suite of four new DNA profiling kits. This paper describes the developmental validation study performed on the PowerPlex^® ESI 16 (European Standard Investigator 16) and the PowerPlex^® ESI 17 Systems. The PowerPlex^® ESI 16 System combines the 11 loci compatible with the UK National DNA Database^®, contained within the AmpFlSTR^® SGM Plus^® PCR Amplification Kit, with five additional loci: D2S441, D10S1248, D22S1045, D1S1656 and D12S391. The multiplex was designed to reduce the amplicon size of the loci found in the AmpFlSTR^® SGM Plus^® kit. This design facilitates increased robustness and amplification success for the loci used in the national DNA databases created in many countries, when analyzing degraded DNA samples. The PowerPlex^® ESI 17 System amplifies the same loci as the PowerPlex^® ESI 16 System, but with the addition of a primer pair for the SE33 locus. Tests were designed to address the developmental validation guidelines issued by the Scientific Working Group on DNA Analysis Methods (SWGDAM), and those of the DNA Advisory Board (DAB). Samples processed include DNA mixtures, PCR reactions spiked with inhibitors, a sensitivity series, and 306 United Kingdom donor samples to determine concordance with data generated with the AmpFlSTR^® SGM Plus^® kit. Allele frequencies from 242 white Caucasian samples collected in the United Kingdom are also presented. The PowerPlex^® ESI 16 and ESI 17 Systems are robust and sensitive tools, suitable for the analysis of forensic DNA samples. Full profiles were routinely observed with 62.5 pg of a fully heterozygous single source DNA template. This high level of sensitivity was found to impact on mixture analyses, where 54–86% of unique minor contributor alleles were routinely observed in a 1:19 mixture ratio. Improved sensitivity combined with the robustness afforded by smaller amplicons has substantially improved the quantity of data obtained from degraded samples, and the improved chemistry confers exceptional tolerance to high levels of laboratory prepared inhibitors.