OBJECTIVETo study the degeneration and regeneration of skeletal muscle after denervation.

METHODSDenervation was carried out in gastrocnemius muscles in 30 adult BALB/C mice by cutting the sciatic nerve. The gastrocnemius muscles were removed at 1, 2, 4, 8, 12, 16 weeks after denervation, respectively. Specimens were processed for histological study and immunohistochemical technique.

RESULTSMuscle fiber atrophy followed by degerneration and regeneration was observed in the early period of denervation. Fusion of the regenerated muscle cells with each other followed by degeneration of the cells and growth of fibro-connective tissue were observed in the later stage. The expression of myoglobin and actin decreased in 1-4 weeks after denervation. The postive expression of the proteins was observed in some 8 weeks' cells and in many degenerated 12-14 weeks' muscle cells.

CONCLUSIONDegeneration and regeneration may coexisted in the denervated muscles. The regenerated muscle cells can't fully develop due to the deficit of nerve regulation and degenerate again. The regenerated muscle cells will melt each other and can't develop to mature muscle fiber in the later stage.

Animals ; Female ; Mice ; Mice, Inbred BALB C ; Muscle Denervation ; Muscle Fibers, Skeletal ; pathology ; Muscle, Skeletal ; innervation ; physiology ; Muscular Atrophy ; physiopathology ; Nerve Regeneration ; physiology ; Sciatic Nerve ; physiology ; surgery

OBJECTIVE: This study aimed to clarify the morphology of the Martin-Gruber anastomosis (MGA) in Chinese. METHODS: One hundred and five Chinese upper limbs (36 males and 20 femalese) were dissected to find the connections between medial nerve and ulnar nerve. The MGA was classified as previously described by Lee. RESULTS: MGA was found in 24 cases (22.9%), in 11 of the 36 male and 5 of the 20 female. There was no obvious difference in the frequency of MGA in both upper limbs. Most MGA ulnar position was located at the medial and distal segment of the forearm. CONCLUSION MGA anatomy could play important role in forensic diagnosis of ulnar nerve injury in Chinese population.
Cadaver ; China/epidemiology* ; Expert Testimony/legislation & jurisprudence* ; Female ; Humans ; Male ; Median Nerve/pathology* ; Muscle, Skeletal/innervation* ; Nervous System Malformations/physiopathology* ; Ulnar Nerve/pathology* ; Upper Extremity/innervation*

Disfigurement of body contour, caused by excessive muscular hypertrophy, can seldom be effectively and safely corrected by lipectomy, liposuction or combined partial myomectomy. This study was conducted to obtain basic knowledge for the development of a safe and effective method of treating patients with excessive and unwelcome muscle hypertrophy. Accordingly, we developed a new experimental rat model, consisting of the peroneal nerve and its target muscles - the anterolateral crural muscle group. After severance of 1/4, 1/2, and 1/1 of the peroneal nerve, functional parameters based on gross movement and electrophysiologic data were monitored. Changes in the external circumference and weight of the anterolateral crural muscle were documented and compared with control sides. Histologic and histomorphometric parameters of the muscle were also documented. Average takeoff latency in 1/4 and 1/2 neurotomy groups was increased to 130% and 154% of the control at 3 months, and 156% and 149% of control at 6months, respectively. Similarly, average peak-to-peak compound action potentials were 72% and 59% of the control at 3months and 57% and 50% of control at 6months. No definite gait disturbances were evident in the partial neurotomy groups. Maximal circumferences of the anterolateral crural muscle group were significantly reduced to 86%, 71% and 66% of the control in the 1/4, 1/2 and 1/1 neurotomy groups at 3 months (p < 0.001), and to 74%, 68% and 64% of the control at 6 months, respectively (p < 0.001). The corresponding weights were 76%, 62%, and 50% of the control sides at 3 months, and 70%, 56%, and 48% at 6 months in 1/4, 1/2 and 1/1 neurotomy groups. Histograms drawn showing the number of muscle fibers per mm2 in cross-sections, showed a total number of 239 +/- 52 in the control group; the size of muscle fibers was mainly medium to large. The more extensive the neurotomy, the greater the was the number of small angulated muscle fibers, up to a total of 1,564 +/- 211. Although more research work and clinical trials are required, we believe that selective neurotomy has the potential of being an effective tool for reducing muscle bulk, and avoiding apparent muscular dysfunction and complications.
Animal ; Electromyography ; Hindlimb ; Hypertrophy ; Muscle, Skeletal/*innervation/*pathology/physiopathology ; Muscular Diseases/*surgery ; Peroneal Nerve/*surgery ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo determine the effect of tension relaxation by small needle knife on the muscle tension and morphology changes of nerve terminals when sustained pressure was applied to muscular tissue.

METHODSRat gracilis muscles were exposed to pressure in vivo at 70 kPa for 2 hours. Sixty rats were divided into three groups: normal, control and experiment group respectively. In all rats except the six normal ones, the lower legs were considered as the control group, and the right left as experiment group. At day 1, 2 and 3, 9 rats from the two groups were randomly selected and sacrificed in order to determine the muscle tension change. At the same time, muscle histology and morphology changes of nerve terminals were observed.

RESULTSAbnormal tension increased in muscles under compression of 70 kPa. At the 1st and 2nd days, there were no significant differences between the two groups. Compared with control group, the tension was lower in experiment group, and there was statistically significant difference (P < 0.01) between the two groups. Exposure of striated muscle tissue to intensive and prolonged compression may pathologically alter its microstructure. Histological evaluation showed that this stiffening accompanied extensive necrotic damage. The changes could not be found in the nerve terminals.

CONCLUSIONDeep muscle tissue that undergoes prolonged compression may significantly increase its stiffness during acute injury. Tension relaxation applied by small needle knife can effectively reduce the mechanical load which is harmful to the whole tissue.

Animals ; Biomechanical Phenomena ; Female ; Male ; Medicine, Chinese Traditional ; Muscle Tonus ; Muscle, Skeletal ; innervation ; pathology ; physiology ; Nerve Endings ; pathology ; Pain Management ; Rats ; Rats, Sprague-Dawley

In the present study we made out an animal model on rabbit whose trigeminus and facialis nerves were simultaneously or only the latter one was severed. The pathological changes in facial muscle atrophy under different nerve injuries were investigated. The degeneration of contractile proteins of upper lip muscle -- myosin and actin was observed. In addition, we also examined the ultrastructural changes in the muscle atrophy in the two above-mentioned nerve injury cases. We observed that the intact trigeminus nerve could delay and lighten the atrophy of facialis-denervated facial muscle and attenuate the degeneration of myosin and actin, as well as decrease the increment of collagen and maintain the ultrastructure of the thick and thin muscle filaments. These results may provide the possibility of improvement of clinical treatment for facial muscle palsy.
Animals ; Denervation ; Facial Muscles ; innervation ; pathology ; Facial Nerve ; physiology ; surgery ; Female ; Muscle Fibers, Skeletal ; diagnostic imaging ; Muscular Atrophy ; pathology ; Rabbits ; Trigeminal Nerve ; physiology ; surgery ; Ultrasonography

We experienced a rare case of winged scapula that was caused by the rupture of the rhomboideus major and the lower trapezius muscles without any nerve injury in a 12 yr old female after she had carried a heavy backpack. Electrodiagnostic study revealed that the onset latencies, amplitudes and conduction velocities were normal in the long thoracic nerve, the spinal accessory nerve and the dorsal scapular nerve. The needle EMG findings were normal as well. An explorative operation was performed and the rupture of the rhomboideus major and lower trapezius muscles was detected. Direct surgical repair of the ruptured muscle was carried out and the deformity was corrected. The anatomical and functional restoration was satisfactorily accomplished.
Weight Lifting/injuries ; Thoracic Nerves/*injuries ; Scapula/anatomy & histology/*physiopathology ; Rupture ; Neurons/metabolism ; Muscle, Skeletal/*injuries/innervation/*pathology ; Humans ; Female ; Electromyography/*methods ; Child

To explore the value of conventional ultrasound combined with shear-wave elastography in the quantitative evaluation of sciatic nerve crush injury in rabbit models. Forty healthy male New Zealand white rabbits were randomly divided into four groups (=10 in each group):three crush injury (CI) groups (2,4,and 8 weeks after crush) and control group (without injury). The thickness and stiffness of the crushed sciatic nerves and denervated triceps surae muscles were measured at different time points and compared with histopathologic parameters. Inter-reader variability was assessed with intraclass correlation coefficients. Compared with the control group,the inner diameters of the sciatic nerves significantly increased in the 2-week CI group [(1.65±0.34) mm (0.97±0.15) mm,=0.00] but recovered to the nearly normal level in the 8-week CI group [(1.12±0.18) mm (0.97±0.15) mm,=0.06];however,compared with control group [(8.75±1.02)kPa],the elastic modulus of the nerves increased significantly in all the CI groups [2-week:(14.77±2.53) kPa;4-week:(19.12±3.46) kPa;and 8-week:(28.39±5.26) kPa;all =0.00];pathologically,massive hyperplasia of collagen fibers were found in the nerve tissues. The thickness of denervated triceps surae muscle decreased gradually,and the elastic modulus decreased 2 weeks after injury but increased gradually in the following 6 weeks;pathologically,massive hyperplasia of collagen fibers and adipocytes infiltration were visible,along with decreased muscle wet-weight ratio and muscle fiber cross-sectional area. The inter-reader agreements were good. Conventional ultrasound combined with shear-wave elastography is feasible for the quantitative evaluation of the morphological and mechanical properties of crushed nerves and denervated muscles.
Animals ; Crush Injuries ; diagnostic imaging ; Elastic Modulus ; Elasticity Imaging Techniques ; Male ; Muscle, Skeletal ; innervation ; pathology ; Rabbits ; Random Allocation ; Sciatic Nerve ; injuries ; Ultrasonography

To study the effects of ciliary neurotrophic factor (CNTF) on denervated skeletal muscle atrophy and to find a new approach to ameliorate atrophy of denervated muscle, a model was established by cutting the right sciatic nerve in 36 Wistar mice, with the left side serving as control. Then they were divided into two groups randomly. CNTF (1 U/ml) 0.1 ml was injected into the right tibial muscle every day in experimental group, and saline was used into another group for comparison. The muscle wet weight, muscle total protein, Ca2+, physiological response and morphology were analyzed on the 7th, 14th and 28th day after operation. Our results showed that compared to control group, there was a significant increase in muscle wet weight, total protein, Ca2+, muscle fiber cross-section area in CNTF group (P < 0.05). CNTF could ameliorate the decrease of tetanic tension (PO), post-tetanic twitch potentiation (PTP), and the prolonged muscle relaxation time (RT) caused by denervation (P < 0.05). The motor end-plate areas 7 days and 14 days after denervation was similar (P > 0.05), but significantly larger 28 days after the denervation (P < 0.05). Our results suggest that CNTF exerts myotrophic effects by attenuating the morphological and functional changes associated with denervation of rat muscles and has protective effects on denervated muscle and motor end plate.
Animals ; Ciliary Neurotrophic Factor ; pharmacology ; Male ; Motor Endplate ; pathology ; physiopathology ; Muscle Denervation ; adverse effects ; Muscle, Skeletal ; innervation ; pathology ; physiopathology ; Muscular Atrophy ; etiology ; prevention & control ; Random Allocation ; Rats ; Rats, Wistar ; Sciatic Nerve ; surgery

BACKGROUND/AIMS: We investigated the electromyography (EMG) findings and demographic, clinical, and laboratory features that may predict the development of malignancy in patients with idiopathic inflammatory myopathy (IIM). METHODS: In total, 61 patients, 36 with dermatomyositis and 25 with polymyositis, were included. Patients were divided into those with and without malignancies, and comparisons were made between the groups in terms of their demographic, clinical, laboratory, and EMG findings. RESULTS: The frequencies of malignancies associated with dermatomyositis and polymyositis were 22% and 8%, respectively. Patients with malignancies showed a significantly higher incidence of dysphagia (odds ratio [OR], 21.50; 95% confidence interval [CI], 3.84 to 120.49), absence of interstitial lung disease (ILD; OR, 0.12; 95% CI, 0.01 to 0.98), and complex repetitive discharge (CRD) on the EMG (OR, 26.25; 95% CI, 2.67 to 258.52), versus those without. After adjustment for age, dysphagia and CRD remained significant, while ILD showed a trend for a difference but was not statistically significant. Multivariate analysis revealed that the CRD conferred an OR of 25.99 (95% CI, 1.27 to 531.86) for malignancy. When the frequency of malignancy was analyzed according to the number of risk factors, patients with three risk factors showed a significantly higher incidence of malignancy, versus those with fewer than two (p = 0.014). CONCLUSIONS: We demonstrated for the first time that CRD on the EMG was an additional independent risk factor for malignancy in IIM. Further studies on a larger scale are needed to confirm the importance of CRD as a risk factor for malignancy in IIM.
Action Potentials ; Adult ; Aged ; Dermatomyositis/complications/*diagnosis/physiopathology ; *Electromyography ; Female ; Humans ; Logistic Models ; Male ; Middle Aged ; Multivariate Analysis ; Muscle, Skeletal/*innervation/pathology ; Neoplasms/*etiology ; Odds Ratio ; Polymyositis/complications/*diagnosis/physiopathology ; Predictive Value of Tests ; Retrospective Studies ; Risk Factors