失神经肌肉的组织、细胞学改变的研究进展

骨骼肌是周围神经系统的靶器官,它的发生、功能和结构的维持都受到运动神经的支配和调节,一旦失去神经支配,骨骼肌将失去收缩功能,肌纤维会逐渐萎缩,同时肌细胞发生一系列的改变。本文就骨骼肌在失神经支配后,发生萎缩的组织、细胞学方面改变的研究进展作一综述。     

Sestrin2在运动防治骨骼肌萎缩中的作用研究进展

骨骼肌约占人体重量的40%，是人体内重要的运动和代谢器官，对于维持机体正常生命活动至关重要。长期卧床、骨骼肌去神经支配、营养不良、增龄等因素均会导致骨骼肌萎缩的发生。运动干预作为一种经济、有效的肌萎缩防治手段，目前已广泛应用于临床骨骼肌萎缩的治疗，但其机制尚未完全明了。研究发现，应激诱导蛋白Sestrins介导了运动调节机体代谢以延缓衰老的进程，且有氧运动显著增加骨骼肌Sestrin2的表达。本文总结近些年来国内外有关Sestrin2在运动防治骨骼肌萎缩中的作用研究进展，分析Sestrin2介导运动改善骨骼肌萎缩的可能机制，以期为运动干预防治肌萎缩提供新的理论依据。     

女性盆底功能障碍性疾病的研究进展

女性盆底功能障碍性疾病(pelvic floor dysfunction,PFD)主要包括女性压力型尿失禁(stress urinaryincontinence,SUI)和盆底脏器脱垂(pelvic organ prolapse,POP)。PFD严重影响妇女身体及心理健康,然而其发病机制尚不十分清楚,本文综述目前国内外有关PFD研究的新进展。1神经、肌肉生理学及形态学研究盆底骨骼肌的张力在维持盆底支持功能中发挥重要作用,而骨骼肌的活动均受神经末梢的支配。Snooks等[1]通过神经电生理研究发现,分娩造成盆底肌肉组织部分去神经支配和阴部神经障碍在POP及SUI患者尤为明显。神经障碍可导致局部肌肉萎缩…     

臂丛神经损伤后不同部位肌肉萎缩的检测和机制探讨

目的 研究臂丛神经损伤后不同部位的失神经骨骼肌的萎缩规律，并探讨细胞凋亡和肌卫星细胞的变化在失神经萎缩骨骼肌中发挥的作用。方法 臂丛神经损伤后手术治疗患者50例，术中切取不同部位的失神经骨骼肌80块，按肌肉部位分为A、B两组，A组为小指展肌34块，B组为肱二头肌46块，每块分别进行HE染色、Masson染色、失神经萎缩肌肉中凋亡细胞核的免疫组化染色和透射电镜观察。结果 （1）随时间的延长，肌细胞萎缩愈加明显，A、B组在各时间段比较，差异均无显著性意义。（2）失神经后骨骼肌中染成牟胶原纤维增多，早期增生并不明显，失神经支配1年以上的肌肉中胶原增生更为显著。不同时间组胶原纤维与骨骼肌细胞面积比较，差异有显著性意义（P＜0.05），同一时间段内A、B组比较，差异均无显著性意义。（3）正常的骨骼肌细胞鲜见凋亡细胞核，失神经后骨骼肌随时间延长，其凋亡细胞核的数量增加，而小指展肌中上升速度较肱二头肌快。（4）随着失神经时间的延长，肌卫星细胞含量迅速下降，小指展肌中肌卫星细胞下降速度较肱二头肌快。结论 不同部位的肌肉失神经支配后，萎缩的肌纤维截面积及胶原纤维的增生情况相似，胶原纤维的增生只在晚期才成为影响神经修复手术疗效的原因之一。细胞凋亡与失神经肌萎缩相关，小指展肌中凋亡细胞核数上升较肱二头肌快，提示细胞凋亡导致的肌细胞核数量减少可能是影响神经修复手术疗效的主要原因之一；肌卫得细胞含量的迅速下降可能也是造成其疗效欠佳的另一原因。     

臂丛及腰骶丛神经损伤及失神经支配骨骼肌的MRI表现

目的探讨臂丛及腰骶丛神经损伤的MRI表现及失神经支配骨骼肌形态及信号改变。资料与方法对21例经肌电图和临床证实的臂丛及腰骶丛神经损伤患者行常规MR序列扫描、三维短恢复时间反转恢复(3D-STIR)序列平扫及增强扫描,分析神经损伤及失神经支配肌肉组织改变的MRI表现。结果 3D-STIR序列能清晰显示臂丛及腰骶丛神经损伤的各种征象,包括创伤性脊膜囊肿、神经根撕脱、神经水肿、增粗神经迂曲、扭曲、神经干断裂等。失神经支配骨骼肌的MRI表现为不同序列上肌肉组织信号增高、肌肉萎缩和脂肪浸润,增强扫描罹患肌肉强化明显。失神经支配肌组织S患/S健与创伤时间呈负相关。结论 MRI上可以清晰显示臂丛及腰骶丛神经损伤情况和失神经支配肌肉形态和信号改变,为临床制定治疗方案提供依据。     

MRI Appearance of Branchial Plexus and Lumbosacral Plexus Injury and Denervated Skeletal Muscles

目的 探讨臂丛及腰骶丛神经损伤的MRI表现及失神经支配骨骼肌形态及信号改变.资料与方法 对21例经肌电图和临床证实的臂丛及腰骶丛神经损伤患者行常规MR序列扫描、三维短恢复时间反转恢复(3D-STIR)序列平扫及增强扫描,分析神经损伤及失神经支配肌肉组织改变的MRI表现.结果 3D-STIR序列能清晰显示臂丛及腰骶丛神经损伤的各种征象,包括创伤性脊膜囊肿、神经根撕脱、神经水肿、增粗神经迂曲、扭曲、神经干断裂等.失神经支配骨骼肌的MRI表现为不同序列上肌肉组织信号增高、肌肉萎缩和脂肪浸润,增强扫描罹患肌肉强化明显.失神经支配肌组织S患/S健与创伤时间呈负相关.结论 MRI上可以清晰显示臂丛及腰骶丛神经损伤情况和失神经支配肌肉形态和信号改变,为临床制定治疗方案提供依据.     

单纯运动或感觉神经损伤在骨骼肌萎缩中的致凋亡作用

目的探讨单纯运动神经或感觉神经损伤在骨骼肌萎缩中的致凋亡作用。方法健康成年SD大鼠30只,随机分为前根切断组(切断左侧L4-L6脊神经前根)、后根切断组(切断左侧L4-L6脊神经后根)和坐骨神经切断组(切断左侧坐骨神经),每组10只。10周后取左右两侧腓肠肌,应用荧光标记、电镜技术以及免疫组化方法观察单纯运动或感觉神经损伤后骨骼肌细胞的凋亡表现及Fas/FasL的表达变化。结果失神经支配10周后,骨骼肌细胞出现各种凋亡变化,细胞核凋亡形态明显,其中后根切断组、前根切断组和坐骨神经切断组的细胞核排列密集程度依次增加,Fas/FasL表达依次增强。电镜观察可见失神经支配的骨骼肌细胞未见典型的凋亡小体,但出现凋亡前期的形态改变。结论运动神经损伤对骨骼肌萎缩的影响大于感觉神经损伤,临床治疗失神经支配的骨骼肌萎缩应优先考虑重建运动神经。     

大鼠臂丛神经损伤后萎缩骨骼肌基因表达谱的变化

目的：研究大鼠臂丛神经损伤后骨骼肌萎缩肌肉中基因表达谱的变化，探寻与去神经肌萎缩有密切关系的基因。方法：应用臂丛神经损伤后骨骼肌萎缩的大鼠模型（鼠数＝6），右侧上肢萎缩肌肉为实验组，左侧正常肌肉为对照组。荧光逆转录标记mRNA，采用鼠基因表达谱芯片检测正常肌肉与萎缩肌肉基因表达谱，并对比分析检测结果。结果；臂丛神经损伤后萎缩骨骼肌基因表达有差异的共148组，其中17组上调，131组下调。结论：在臂丛神经损伤的萎缩的骨骼肌中，与细胞凋亡相关基因的表达发生改变，促使细胞凋亡。一些与线粒体相关的基因表达的改变提示萎缩肌肉中线粒体的功能发生异常，糖、蛋白质和脂肪代谢关键酶基因表达的下调导致肌细胞内能量代谢严重障碍。     

神经断端埋植骨骼肌重建支配的实验形态观察

神经断端埋植骨骼肌重建支配的实验研究，从组织学、酶组织化学和超微结构方面，追踪观察了神经再生的动态生长变化过程。认为既往常用于神经镀金镀银染色法，在光镜下不能区别新旧神经及其运动终板．而在透射电镜下形态变化可资区别，并描述了其超微结构特点。结果证实神经近端埋植骨骼肌为创伤情况下周围神经修复之有效的方法，从而为临床应甩提供了形态学依据。     

去神经化和神经再支配骨骼肌的连续性MR成像与功能结果的相关性

摘要目的前瞻性评估病人的去神经化和神经再支配骨骼肌的短反转时间反转恢复(STIR)MR信号强度随时间出现的变化。材料与方法本研究得到了机构评审委员会的支持,所有病人均签署了知情同意书。23例前臂正中神经或尺神经创伤性横断伤病人,外科神经修补术后接受了前瞻性的12个月随访,神经修补后1、3、6、9、12个月采集选择性手部肌肉内的STIRMR影像,半定量分析去神经化以及神经再支配的肌肉信号强度。     

背根神经节端侧吻合延缓失神经骨骼肌萎缩的实验研究

 目的 建立背根神经节端侧吻合营养失神经腓肠肌的动物模型,观察其延缓失神经骨骼肌萎缩的作用.方法 选用48只SD大鼠,随机分成两组,实验组:腓肠肌失神经支配加背根神经节端侧吻合;对照组:腓肠肌单纯完全失神经支配.于术后4、8、12周各时间段,分别测定腓肠肌纤颤电位波幅、肌湿重、肌细胞直径及截面积,并观察背根神经节中感觉神经元的变化,判断肌萎缩的程度.结果 术后1～3个月背根神经节中均见到存活的感觉神经元,纤颤电位波幅实验组大于对照组;术后4、8、12周,实验组的肌湿重,肌细胞直径及截面积明显高于对照组.结论 周围神经损伤后的3个月内,背根神经节端侧吻合后感觉神经元能有效的延缓失神经骨骼肌萎缩.     

高压氧对大鼠神经离断后运动神经元和失神经肌肉影响的初步观察

目的：观察大鼠神经离断后，高压氧（HBO）对脊髓前角运动神经元变性和腓肠肌萎缩的影响。方法：采用大鼠坐骨神经横断伤模型。在动物模型分别接受不同疗程的常压空气（NA）、常氧高压（N2－O2）和HBO治疗后，进行脊髓切片尼氏体染色，观察脊髓前角运动神经元的变性存活状况；测量腓肠肌湿重，观察神经损伤后肌肉萎缩的情况。结果：治疗15d，HBO组脊髓前角运动神经元的变性坏死程度比NA组和N2－O2组轻（P＜0．05）。治疗8d，HBO组的腓肠肌湿重比NA组和N2－O2组大（P＜0．01）。结论：HBO能够减轻脊髓前角运动神经元变性坏死程度和延缓失神经肌肉的萎缩。     

MRI appearance of muscle denervation

Muscle denervation results from a variety of causes including trauma, neoplasia, neuropathies, infections, autoimmune processes and vasculitis. Traditionally, the diagnosis of muscle denervation was based on clinical examination and electromyography. Magnetic resonance imaging (MRI) offers a distinct advantage over electromyography, not only in diagnosing muscle denervation, but also in determining its aetiology. MRI demonstrates characteristic signal intensity patterns depending on the stage of muscle denervation. The acute and subacutely denervated muscle shows a high signal intensity pattern on fluid sensitive sequences and normal signal intensity on T1-weighted MRI images. In chronic denervation, muscle atrophy and fatty infiltration demonstrate high signal changes on T1-weighted sequences in association with volume loss. The purpose of this review is to summarise the MRI appearance of denervated muscle, with special emphasis on the signal intensity patterns in acute and subacute muscle denervation.     

Sequential MR imaging of denervated muscle: experimental study

BACKGROUND AND PURPOSE: MR changes in denervated muscles have been reported to occur within days up to several weeks after peripheral nerve damage. The purpose of this experimental study was to investigate the longitudinal changes in denervated muscles by using MR imaging. METHODS: In 12 Lewis rats, the left sciatic nerve was transected at the level of the proximal thigh. MR imaging of both legs was performed before and 1 hour, 24 hours, 48 hours, 7 days, 14 days, 28 days, and 2 months after the procedure. The MR protocol included T1-weighted spin-echo, T2-weighted double turbo spin-echo, and turbo inversion recovery magnitude (TIRM) sequences obtained in the axial plane. Signal intensities (T2-weighted double turbo spin-echo and TIRM sequences) and the T2 TR (T2-weighted double turbo spin-echo sequence) were recorded for the soleus, peroneal, and gracilis muscles of both sides. Moreover, the circumferences of both lower legs were determined on the basis of T1-weighted images. RESULTS: Twenty-four hours after denervation, a signal intensity increase in the denervated peroneal and soleus muscles was present on TIRM images. On T2-weighted images, only the peroneal muscle exhibited slightly increased signal intensities and T2 TR. Forty-eight hours after nerve transection, the denervated soleus and peroneal muscles revealed prolonged T2 TR and marked increased signal intensities on T2-weighted and TIRM images when compared with the contralateral side, which further increased at or less than 2 months after denervation. Muscle atrophy of the denervated muscles was present as early as 7 days after denervation and was also increased at follow-up examinations. CONCLUSION: The TIRM sequence is more sensitive than is T2-weighted imaging in the detection of signal intensity changes in denervated muscle. These changes occur as early as 24 (TIRM sequence) and 48 (T2-weighted sequence) hours, respectively, after complete transection of the sciatic nerve in rats and precede muscle atrophy. The sensitivity to early signal intensity changes in denervated muscles may support the use of MR imaging in the diagnosis of peripheral nerve lesions.     

Denervation syndromes of the shoulder girdle: MR imaging with electrophysiologic correlation

Objective. To investigate the use of MR imaging in the characterization of denervated muscle of the shoulder correlated with electrophysiologic studies. Design and patients. We studied with MR imaging five patients who presented with shoulder weakness and pain and who underwent electrophysiologic studies. On MR imaging the distribution of muscle edema and fatty infiltration was recorded, as was the presence of masses impinging on a regional nerve. Results. Acute/subacute denervation was best seen on T2-weighted fast spin-echo images with fat saturation, showing increased SI related to neurogenic edema. Chronic denervation was best seen on T1-weighted spin-echo images, demonstrating loss of muscle bulk and diffuse areas of increased signal intensity within the muscle. Three patients showed MR imaging and electrophysiologic findings of Parsonage Turner syndrome. One patient demonstrated an arteriovenous malformation within the spinoglenoid notch, impinging on the suprascapular nerve with associated atrophy of the infraspinatus muscle. The fifth patient demonstrated fatty atrophy of the teres minor muscle caused by compression by a cyst of the axillary nerve and electrophysiologic findings of an incomplete axillary nerve block. Conclusion. MR imaging is useful in detecting and characterizing denervation atrophy and neurogenic edema in shoulder muscles. MR imaging can provide additional information to electrophysiologic studies by estimating the age (acute/chronic) and identifying morphologic causes for shoulder pain and atrophy. Received: 5 May 1999 Revision requested: 22 July 1999 Revision received: 28 July 1999 Accepted: 29 July 1999     

转化生长因子受体Ⅱ与去神经性肌萎缩的相关性研究

目的研究去神经致肌萎缩和纤维类型转化的分子机制,探讨TβRII-SMAD信号通路在此过程中的相关性。方法取10只C57BL/6小鼠,右后肢坐骨神经离断,左后肢假手术对照。Real Time PCR(RT-PCR)检测术后14 d比目鱼肌和跖肌萎缩基因MAFbx,MuRF-1,及PGC-1α,MHCIIb,TβRII的表达变化。结果去坐骨神经后萎缩基因MAFbx,MuRF-1及MHCIIb在比目鱼肌和跖肌明显上调;PGC-1α,TβRII的表达在比目鱼肌和跖肌呈现差异性变化。结论 MAFbx,MuRF-1和PGC-1α在肌萎缩过程中发挥重要作用,TβRII可能参与了对肌萎缩的调节。     

Diffusion-weighted MRI of denervated muscle: a clinical and experimental study

Objective  The aim of this study was to investigate skeletal muscle denervation using diffusion-weighted magnetic resonance imaging (DWMRI). Materials and methods  Sciatic nerve axotomy was performed in a group of nine New Zealand White rabbits, and electromyographic (EMG), pathological, and DWMRI studies were conducted on ipsilateral hamstring muscles 1 and 8 days after axotomy. In addition, DWMRI studies were carried out on leg muscles of ten patients with acute and subacute lumbosacral radiculopathy. Results  High intensity signals on short tau inversion recovery (STIR) magnetic resonance imaging and an increased apparent diffusion coefficient (ADC) were observed in denervated muscles of the animals 1 and 8 days after axotomy as well as in denervated muscles of the patients with radiculopathy. In the clinical study, ADC was 1.26 ± 0.18 × 10⁻⁹ m²/s in normal muscle and increased to 1.56 ± 0.23 × 10⁻⁹ m²/s in denervated muscles (p = 0.0016). In animals, EMG and muscle pathological studies were normal 1 day after axotomy, and the muscles demonstrated spontaneous activity on EMG and neurogenic atrophy on histological studies 7 days later. Conclusion  This DWMRI study demonstrates that enlargement of extracellular fluid space in muscle denervation is an early phenomenon occurring several days before the appearance of EMG and histological abnormalities. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Nathalie Holl and Andoni Echaniz-Laguna contributed equally to this work.     

Diffusion-weighted MRI, dynamic susceptibility contrast MRI and ultrasound perfusion quantification of denervated muscle in rabbits

Objective  

The purpose of this study was to assess denervated muscle perfusion using dynamic susceptibility contrast MRI (DSCMRI) and contrast-enhanced ultrasound (CEUS), and to measure denervated muscle apparent diffusion coefficient (ADC) on b1000 diffusion-weighted MRI (DWMRI) at 3 T in order to clarify whether muscle denervation leads to an increase in the extracellular extravascular space, or an increase in blood flow—or both.