An autoradiography study of myogenic cell movement in avian limb buds following heterospecific and homospecific transplantation

Summary Species specificity and the use of quail cells as a marker in the study of myogenic cell movement in the developing avian limb was investigated. In order to establish whether or not observed myogenic cell movement in quail/chick limb transplantation experiments might be an artefact produced by cellular interaction between these cell types a series of homospecific and heterospecific transplantations was performed. Chick wing fragments (staged 20–25 H.H.) were labelled with tritiated thymidine and inserted into unlabelled chick wing bud (homospecific) in ovo. In addition, quail wing fragments were also labelled with tritiated thymidine and transplanted in the same manner into chick (heterospecific), so that the effectiveness of tritium as a marker could be assessed. After 4 days post-incubation, myogenic cell movement was detected in eight out of the ten homospecific transplantions performed. Myogenic cell movement in avian limbs is therefore not produced by interaction between chick and quail cells, as migration was also detected in the chick/chick transplants. Nonetheless, heterospecific transplantation results revealed that autoradiographic methods failed to reveal completely the true extent to which myogenic cell movement occurred, because tritiated thymidine was subject to dilution.     

消肿止痛膏对腓肠肌损伤大鼠MyoD mRNA与蛋白表达的影响

目的基于微小RNA表达机制,探讨消肿止痛膏对大鼠骨骼肌损伤后重塑和修复的影响。方法通过钝挫伤模型的方法建立大鼠腓肠肌损伤模型,观察消肿止痛膏对大鼠损伤后4、7、14、21天定量PCR检测腓肠肌MyoD mRNA与蛋白表达水平,探讨消肿止痛膏对大鼠腓肠肌钝挫伤模型的肌肉重塑与修复的作用机制。结果治疗组MyoD mRNA表达与蛋白表达水平在造模后14天、21天均显著高于空白组与模型组(P<0.05),进一步证实消肿止痛膏在骨骼肌重塑及修复过程中所起的重要作用。MyoD在损伤后7天上升,其后表达一直维持在较高水平,至损伤后21天仍可以表达出较高水平。与模型组相比较,其表达的高峰期在14天左右,其后则基本回归到一般状态。结论大鼠腓肠肌损伤后,在自然修复过程中,生肌调节因子的表达水平呈现上升-回落的趋势,其中损伤后7～14天,为其表达的高峰期。MyoD的表达水平呈现上升趋势,即使至损伤后21天,其表达仍未见明显下降趋势,可见消肿止痛软膏可以促进MyoD的表达。消肿止痛软膏可以促进MyoD的表达,可以调节骨骼肌的再生修复,提示消肿止痛膏可以通过基因调控,发挥对骨骼肌损伤后的再生修复作用。     

Studies on the effects of felodipine on the vascular resistance and reactivity in pentobarbital anesthetized dogs

Summary Bilateral perfused hindlimb preparations in pentobarbital anesthetized dogs were utilized in the present study to evaluate vasodilator effects of felodipine, in the presence and in the absence of sympathetic neurogenic tone. Vascular resistance was evaluated by establishing pressure-flow characteristics. A lower dose of this agent (0.01 mol/kg i.v.) produced significant reductions in the systemic arterial blood pressure and vascular resistance only in the innervated but not in the denervated limb. This effect was shown to be due to interference with noradrenaline induced vasoconstriction. However, a tenfold higher dose of felodipine (0.1 mol/kg i.v.) was indeed effective in attenuating resistance in the denervated vascular bed; this ability of the higher dose (0.1 mol/kg) to inhibit vascular resistance may be due to an additional intracellular action of this drug affecting myogenic tone and/or due to inhibition of the vascular effects of the endogenous renin-angiotensin system. In the present experimental model, felodipine, a dihydropyridine calcium antagonist, was equally effective in inhibiting either alpha₁- or alpha₂-mediated vasoconstriction. These data suggest that the ability of felodipine to interfere with sympathetic vasoconstrictor mechanisms primarily contributes to its hypotensive effects in the barbiturate-anesthetized dogs.     

脐血间质干细胞经肌源性诱导后细胞内游离钙的变化

目的研究3种不同的肌源性诱导方法对脐血间质干细胞（mesenchymal stem cells,MSCs）进行诱导后细胞内Ca2＋调控系统分化的影响。方法 2007年1月至2010年4月上海交通大学医学院附属新华医院采用5-氮杂胞嘧啶核苷（5-azacytidine,5-aza）、心肌裂解液和心肌诱导液分别诱导犬脐血MSCs。采用激光共聚焦显微镜检测5-aza、心肌裂解液和心肌诱导液诱导的细胞、心肌细胞和MSCs内Ca2＋荧光探针Fluo-3/AM结合的Ca2＋,每份细胞选取2~5个视野,每一种细胞观察记录30个视野,取每1 min摄得的10张图象的平均荧光强度值,以光密度值（OD）反映细胞内游离Ca2＋浓度;并连续监测细胞内游离Ca2＋浓度的变化。结果经3种方法诱导后细胞内游离Ca2＋浓度均高于心肌细胞内游离Ca2＋浓度（F=59.400,P=0.000）。5-aza、心肌裂解液和心肌诱导液诱导的细胞内游离Ca2＋浓度差异有统计学意义（F=18.988,P=0.000）。5-aza诱导的细胞内游离Ca2＋浓度与心肌裂解液诱导的细胞比较差异无统计学意义（OD 1 076.88±44.65 vs.1 040.90±37.48,P=0.186）,但其浓度高于心肌诱导液诱导的细胞（OD 1 076.88±44.65 vs.973.91±46.49,P=0.001）,心肌裂解液诱导的细胞内游离Ca2＋浓度高于心肌诱导液诱导的细胞（OD 1 040.90±37.48 vs.973.91±46.49,P=0.001）。3种诱导方法诱导后的细胞内游离Ca2＋呈自发性波动,与心肌细胞相似,但其频率和幅度有明显差异。5-aza、心肌裂解液诱导后的MSCs在KCl刺激下能使细胞内Ca2＋瞬时释放,心肌诱导液诱导后的MSCs对KCl也有反应,但不能诱发Ca2＋释放,而是使Ca2＋释放时间延长。结论 5-aza诱导、心肌裂解液和心肌诱导液诱导对MSCs的Ca2＋调控系统有分化作用,3种方法的效果不同,其产生差异的原因和效果的优劣需进一步实验阐明。     

不同生肌药治愈感染性伤口的时间比较

目的 探讨不同生肌药治疗感染性伤口的愈合时间.方法 2009年1月～2010年12月,北京市顺义区第二医院外科分别应用湿润烧伤膏、京万红软膏各治疗15例感染性伤口患者,将两组患者伤口愈合时间进行比较.结果湿润烧伤膏组患者伤口愈合时间明显短于京万红软膏组,差异有统计学意义.结论湿润烧伤膏治疗感染性伤口,伤口愈合更快.     

利用基因芯片技术阐述中药解毒生肌膏对大鼠糖尿病足溃疡作用的分子机制

目的 采用基因芯片技术探讨中药解毒生肌膏对大鼠糖尿病足溃疡的作用机制.方法 腹腔注射链脲佐菌素复制糖尿病大鼠模型,喂养到6个月时结扎腘动脉下端并切断,7个月时造成足底部皮肤深Ⅱ度烫伤复制大鼠糖尿病足溃疡模型.将模型大鼠按随机数字表法分为中药组、表皮生长因子组、模型对照组,每组15只.烫伤后分别给予中药解毒生肌膏、重组人表皮生长因子、生理盐水局部外用,每2d换药1次,治疗30 d后观察大鼠治疗前后溃疡面积及愈合情况.提取各组溃疡区组织总RNA,应用大鼠细胞因子芯片进行组间基因比较.结果 与模型对照组比较,表皮生长因子组有25个基因发生改变,其中上调23个,下调2个;中药组有30个基因发生改变,其中上调29个,下调1个.与表皮生长因子组比较,中药组有16个基因发生改变,其中上调11个,下调5个.这些基因涉及神经营养因子、趋化因子.结论 中药解毒生肌膏和表皮生长因子能够通过影响各种炎症反应过程中的细胞因子平衡,促进糖尿病足溃疡的愈合,其中以中药解毒生肌膏的效果更好.     

成肌调节因子Myf-5在失神经骨骼肌萎缩不同时段的表达

背景：成肌调节因子Myf-5是参与肌肉发生过程分子调控、启动和维持骨骼肌细胞生长发育的重要基因,可能与失神经骨骼肌萎缩的发生有关。 目的：观察不同部位、不同时段骨骼肌失神经支配后成肌调节因子Myf-5基因的表达情况。 设计、时间及地点：随机对照动物实验,于2008-03/04在山西医科大学完成。 材料：选择健康8周龄雄性SD大鼠24只,随机分成4组,即假手术组(有神经支配)、去神经2 d组、去神经7 d组、去神经28 d组,每组6只。 方法：假手术组不切断坐骨神经,仅做假手术。去神经组右下肢后部中段切断坐骨神经1 cm以上,分别于去神经第2,7,28天用脊椎脱臼法处死大鼠,分离出右小腿的胫骨前肌、比目鱼肌、腓肠肌、跖肌标本。 主要观察指标：用反转录-聚合酶链反应技术检测各组肌肉Myf5 mRNA表达情况,抗Myf-5 多克隆抗体免疫组织化学染色(ABC 法),测量灰度值。 结果：去神经骨骼肌早期,Myf-5的mRNA在去神经支配后第2,7,28天均表达上调(P < 0.05)。Myf-5 抗体阳性染色细胞核数在SD大鼠骨骼肌失神经28 d时的肌卫星细胞中最多。 结论：Myf-5在大鼠失神经骨骼肌萎缩早期不同肌肉表达均为上调。大鼠骨骼肌失神经支配后早期肌卫星细胞中Myf-5表达上调。     

转化生长因子-茁1在人横纹肌肉瘤肌源性分化中的作用

目的:探讨转化生长因子-茁1(TGF-茁1)在横纹肌肉瘤肌源性分化中的作用。方法:采用细胞培养、逆转录多聚酶链式反应(RT-PCR)及免疫荧光染色观察TGF-茁1对横纹肌肉瘤细胞系RD肌源性分化相关指标的影响,并用免疫组化SP法,检测49例横纹肌肉瘤组织中TGF-茁1表达与肌球蛋白重链(MyHC)之间的相关性。结果:TGF-茁1可明显抑制RD细胞肌球蛋白重链mRNA和蛋白的表达。用TGF-茁1处理RD细胞后,肌球蛋白重链和肌节肌动蛋白(Sarcomeric-Actin)阳性着色细胞数明显下降(P<0.05)。MyoD1的表达在处理前后未见明显差异。横纹肌肉瘤组织中TGF-茁1表达与肌球蛋白重链呈明显负相关(P<0.05)。结论:TGF-茁1可抑制RD细胞的肌源性分化,这一作用可能不依赖于MyoD1的调节。TGF-茁1信号传导通路可能与横纹肌肉瘤的肌源性分化受阻有关。     

Cellular and molecular mechanisms underlying age-related skeletal muscle wasting and weakness

Some of the most serious consequences of ageing are its effects on skeletal muscle. The term 'sarcopenia' describes the slow but progressive loss of muscle mass with advancing age and is characterised by a deterioration of muscle quantity and quality leading to a gradual slowing of movement and a decline in strength. The loss of muscle mass and strength is thought to be attributed to the progressive atrophy and loss of individual muscle fibres associated with the loss of motor units, and a concomitant reduction in muscle 'quality' due to the infiltration of fat and other non-contractile material. These age-related changes in skeletal muscle can be largely attributed to the complex interaction of factors affecting neuromuscular transmission, muscle architecture, fibre composition, excitation-contraction coupling, and metabolism. Given the magnitude of the growing public health problems associated with sarcopenia, there is considerable interest in the development and evaluation of therapeutic strategies to attenuate, prevent, or ultimately reverse age-related muscle wasting and weakness. The aim is to review our current understanding of some of the cellular and molecular mechanisms responsible for age-related changes in skeletal muscle.