ObjectiveTo investigate the expression of miRNA-1 in denervated skeletal muscle at different periods, and to explore effects of passive movement on the expression of miRNA-1 and differentiation of myoblasts in denervation-induced skeletal muscle atrophy in rats.
MethodsTwenty-seven Sprague Dawley rats, weighing (200±10) g, were randomly divided into sham-operated group (group A, n=3), denervated group (group B, n=12), and passive movement group (group C, n=12). After the right sciatic nerve was exposed and dissociated, the sciatic nerve of 1 cm in length was removed in groups B and C; resection was not performed in group A. At 1 day after operation, passive flexion and extension movement was performed on the right hind limb in group C. At 6 hours in group A and at 3, 7, 14, and 28 days in groups B and C, 3 rats were sacrificed to measure the wet weight ratio of gastrocnemius muscle, to observe the diameter of the gastrocnemius muscle cell and evaluate the muscle atrophy by HE staining; RT-PCR was used to detect the mRNA expression of miRNA-1 and myocyte differentiation factor (MyoD), and immunohistochemistry to determine the protein expression of MyoD.
ResultsAtrophy in various degrees was observed in denervated gastrocnemius muscle of groups B and C. The muscle fiber arranged in disorder and the diameter of the muscle cells decreased gradually with the time, without normal structure and morphology. The wet weight ratio and the cell diameter of the gastrocnemius in groups B and C were significantly less than those in group A (P<0.05); the wet weight ratio at 7, 14, 28 days and the cell diameter at 7, 14 days of group B were significantly greater than those of group A (P<0.05). The expressions of miRNA-1 and MyoD mRNA gradually increased with time in groups B and C, but were significantly less than those of group A at each time point (P<0.05). At 7, 14, and 28 days after operation, the expressions of miRNA-1 and MyoD mRNA in group C were significantly higher than those in group B (P<0.05). Immunohistochemical staining showed positive expression of MyoD in groups A, B, and C at each time point, but higher expression was observed in groups B and C than group A; the expression increased with time in groups B and C, and it was significantly higher in group C than group B. The correlation analysis results showed that the overall change trend of miRNA-1 and MyoD had no relation with the gastrocnemius wet weight ratio at 3 and 7 days (P>0.05), and had positive correlation at 14 and 28 days (P<0.05); positive correlation was found between the relative expression of MyoD and miRNA-1 mRNA (P<0.05).
ConclusionPassive movement can prevent amyotrophy by increasing the expression of miRNA-1 and promoting the differentiation of myoblasts.
Objective To explore the rule of changes in the myoblast stem cells (satellite cells) in the denervated and innervated muscles and to find out thecellular mechanism of the changes in the muscle morphology and function. Methods The denervated muscleatrophy models were established from 27 Wistar rats aged 1 month. One to six months after operation, examinations of the histology, histochemistry, and morphology were performed on the specimens from the bilateral triceps muscle of the calves of 3 rats in each month. Meanwhile, examination of the cell biology was performed on the specimens from the bilateral triceps muscleof the calves of 1 rat 1, 2 and 3 weeks after operation, and monthly for 1-6 months after operation. The innervation models were established from 35 Wistar rats aged 1 month. Immediately after the denervation, and monthly for 1-6 months after operation, 5 denervated rats underwent the nerve implantation. The changes in the electrophysiological index were observed dynamically until 8 weeks after the nerve implantation.Results After the denervation, the muscle wet weight and the muscle cell area decreased rapidly, but the content of the collagen fibers increased gradually. The number of the nucleus in the period of proliferationwas the greatest 3-4 months after the denervation, and then decreased rapidly.The muscle satellite cells began to increase obviously 3 weeks after the denervation, but 2 months later they decreased rapidly and 4 months later the number of the cells was the smallest. Four to five weeks after innervation, the muscle action potential could be induced, and the best innervation effect could be achieved in the implanted nerve after the 2-3 months on denervation, and at this time the differentiation ability of the satellite cells was the best. Conclusion Four months after the denervation of the skeletal muscle, an extremely small number of the satellite cells can make the muscle enter the irreversible atrophy. However, when the innervation is performed 2-3 months after the denervation, the actively-growing satellite cells can promote a better functional recovery ofthe atrophic muscle.
The automatic recognition technology of muscle fatigue has widespread application in the field of kinesiology and rehabilitation medicine. In this paper, we used surface electromyography (sEMG) to study the recognition of leg muscle fatigue during circuit resistance training. The purpose of this study was to solve the problem that the sEMG signals have a lot of noise interference and the recognition accuracy of the existing muscle fatigue recognition model is not high enough. First, we proposed an improved wavelet threshold function denoising algorithm to denoise the sEMG signal. Then, we build a muscle fatigue state recognition model based on long short-term memory (LSTM), and used the Holdout method to evaluate the performance of the model. Finally, the denoising effect of the improved wavelet threshold function denoising method proposed in this paper was compared with the denoising effect of the traditional wavelet threshold denoising method. We compared the performance of the proposed muscle fatigue recognition model with that of particle swarm optimization support vector machine (PSO-SVM) and convolutional neural network (CNN). The results showed that the new wavelet threshold function had better denoising performance than hard and soft threshold functions. The accuracy of LSTM network model in identifying muscle fatigue was 4.89% and 2.47% higher than that of PSO-SVM and CNN, respectively. The sEMG signal denoising method and muscle fatigue recognition model proposed in this paper have important implications for monitoring muscle fatigue during rehabilitation training and exercise.
The rectus femoris muscles of rabbits were used as muscle model. The electrical stimulation which resembled the normal motor-unit activity was used to observe its effects on free transferred muscle. After three months, the moist muscle weight (MW), its maximum cross-section area, its contractility and its histochemical characteristics were examined. The results showed that the function and morphology of the muscles were well preserved. These findings might encourage its clinical application.
On the basis of laboratory research of the reinnervation of poralyysed musele by implanting muscle bundies with neurovascular pedicle ( NVMBI),this method was applied clinically to trcat paralysed musele on extremities and trunks with quite satisfactory result.Detail description of preoperative exammation,operation design,surgical procedure and potoperative management were presented。the mechanism and reason of the good result were dscussed. The anatomical characteristics of the NVMBI we...
Objective To observe the delaying effect of neural stem cell (NSC) transplantation on denervated muscle atrophy after peri pheral nerve injury, and to investigate its mechanism. Methods NSCs were separated from the spinal cords of green fluorescent protein (GFP) transgenic rats aged 12-14 days mechanically and were cultured and induced to differentiate in vitro. Thirty-two F344 rats, aged 2 months and weighed (180 ± 20) g, were randomized into two groups (n=16 per group). The animal models of denervated musculus triceps surae were establ ished by transecting right tibial nerve and commom peroneal nerve 1.5 cm above the knee joints. In the experimental and the control group, 5 μL of GFP-NSCsuspension and 5 μL of culture supernatant were injected into the distal stump of the tibial nerve, respectivel. The generalcondition of rats after operation was observed. At 4 and 12 weeks postoperatively, the wet weight of right musculus tricepssurae was measured, the HE staining, the Mallory trichrome staining and the postsynaptic membrane staining were adopted for the histological observation. Meanwhile, the section area of gastrocnemius fiber and the area of postsynaptic membrane were detected by image analysis software and statistical analysis. Results The wounds in both groups of animals healed by first intension, no ulcer occurred in the right hind l imbs. At 4 and 12 weeks postoperatively, the wet weight of right musculus triceps surae was (0.849 ± 0.064) g and (0.596 ± 0.047) g in the experimental group, respectively, and was (0.651 ± 0.040) g and (0.298 ± 0.016) g in the control group, respectively, showing a significant difference (P lt; 0.05). The fiber section area of the gastrocnemius was 72.55% ± 8.12% and 58.96% ± 6.07% in the experimental group, respectively, and was 50.23% ± 4.76% and 33.63% ± 4.41% in the control group, respectively. There were significant differences between them (P lt; 0.05). Mallory trichrome staining of muscle notified that there was more collagen fiber hyperplasia of denervated gastrocnemius in the control group than that in the experimental group at 4 and 12 weeks postoperatively. After 12 weeks of operation, the area of postsynaptic membrane in the experimental group was (137.29 ± 29.14) μm2, which doubled that in the control group as (61.03 ± 11.38) μm2 and was closer to that in normal postsynaptic membrane as (198.63 ± 23.11) μm2, showing significant differences (P lt; 0.05). Conclusion The transplantation in vivo of allogenic embryonic spinal cord NSCs is capable of delaying denervated muscle atrophy and maintaining the normal appearance of postsynaptic membrane, providing a new approach to prevent and treat the denervated muscle atrophy cl inically.
Objective To study the clinical characteristics of myotonic dystrophy. Method Patient records in West China Hospital, Sichuan University and China Biological Medicine Database (CBM-disc 1980-1999) were searched. Demographic data, clinical manifestations, laboratory findings of patients with myotonic dystrophy were analyzed. Results Of the total 97 patients, 64 cases were male, and 33 were female. Mean age was 28.5 years old. Ninety percent of patients had a family history. The frequency of symptoms in turn was myotonia (99%), muscle weakness (97%), muscle atrophy (85%), cataract (63%), hair losing or bald (57%) and gonadal atrophy (37%), sexuality disfunction (33%), heart damage (11%), intelligence impairment (11%), hypothyroid or disfunction of adrenal gland (8%), mental state disorders (8%). Conclusions In this group of patients, myotonia, muscle weakness and muscle atrophy were most common symptoms. In addition, some other systemic symptoms were common, such as cataract, hair losing, bald and gonadal atrophy. The clinical manifestations of myotonic dystrophy were complex.
Objective To introduce the experience about thereconstruction of median sternotomy wound dehiscence. Methods From February 2002 to October 2004, 10 patients with median sternotomy wound dehiscence due to coronary artery revascularization were treated. There were 7 males and 3 females, aging from 68 to 76 years. The sizes of defects ranged from3 cm×5 cm to 5 cm×15 cm. After debridement of necrotic soft tissue, sternum and rib, infected median sternotomy wound was reconstructed with rectus abdominis myocutanous flap, pectoralis major myocutanous flap and latissimus dorsi flap or single muscle flap. The sizes of flaps ranged from 3 cm×5 cm to 5 cm×16 cm.Results Allpatients were followed up from 3 to 11 months with anaverage of 6 months. All the patients achieved healing by first intention with normal respiration and normal function of upper limbs. The wound of donor site healed well.No abdominal hernia and other complications occurred. The wound of donor site healed well.The results were satisfactory.Conclusion According to different stages of the disease and different conditions of an operation, the surgical management should vary with each individual.
Objective To compare the long-term results between theMckay procedure and the musclestrength balancing procedure in treatment of congenital clubfoot (CCF).Methods Thirty-seven children with 54 clubfeet were treated by the muscle-strength balancing procedure (31 feet) or the Mckay procedure (23 feet).There were 27 males (38 feet) and 10 females (16 feet). The average age at the time of surgery was 1.2 years (range, 5 months to 3.5 years). The deformity occurred on the left side in 7 patients, on the right side in 13, and on both sides in 17. During the musclestrength balancing procedure, the anterior tibial tendonwas transplanted to the middle or the lateral cuneiform, and the Achilles tendon was lengthened. During the Mckay procedure, the complete releasing of the softtissues and the lengthening of the tendons were performed routinely; in addition, the abductor hallucis was also excised. The clinical outcomes were evaluated with the Diméglio classification method. According to the Diméglio scoring system, 3 clubfeet were at Grade Ⅱ (score, 6-10); 26 clubfeet at Grade Ⅲ (score, 11-15); 25 clubfeet at Grade Ⅳ (score, 16-20). Based on the Diméglio grading system, all the patients were divided into two groups before operation. Group Aconsisted of 29 feet at Grade Ⅱ or Ⅲ (score, 12.55±1.84); Group B consistedof 25 feet at Grade Ⅳ (score, 17.20±1.08). The score in the group undergoingthe musclestrength balancing procedure was 14.16±2.83, and the score in the group undergoing the Mckay procedure was 15.43±2.63. Results All the patients were followed up for an average of 8.2 years (range, 5.0-10.5 years). According to the Diméglio grading system, 32 patients were at Grade Ⅰand 22 patients at Grade Ⅱ, and none of the patients at Grade Ⅲ or Ⅳ. Two patients undergoing the Mckay procedure developed the postoperative incision infection, but the incision wound healed after the dressing changes. The Diméglio score was 4.07±1.25 in Group A and 6.52±1.74 in Group B after operation, with a significant difference when compared with before operation (Plt;0.05). In Group A the two procedureshad no significant difference in effectiveness (Pgt;0.05); however, in Group B they had a significant difference (Plt;0.05). Judging by the correction degrees for the deformity on the different planes, the two procedures had no significant difference for correcting the equinus of hind foot (Pgt;0.05); however, in the correction degrees for the cross-foot and supination or adduction of the anterior foot, the Mckay procedure was significantly finer than the muscle-strength balancing procedure. It has a good biocompatibility. The mechanical test has showed that the Mckay procedure had the best result in the correction of the forefoot adduction. Conclusion For treatment of congenital clubfoot at Grades Ⅰ-Ⅲ, the musclestrength balancing procedure can achieve an excellent correction result; for treatment of congenital clubfoot at Grade Ⅳ, the Mckay procedure should be performed. No matter whichprocedure, the abductor hallucis excision is recommended to prevent poor correction for the anterior foot adduction.
our patients with brachial plexus root arulsion, who had undergone various nerve operationswith no functional recovery of the limb, were treated with transfer of sternocledomastoid muscle toreconstruct the function of elbow fleaion. The sternocleidomastoid muscle was datached from itsincertions and was lengthened by fascia lata graft from the thigh , and then , was transferred under theclavicle to the radiai shaft just distal to the radial tuberosity. After the recostruction, The potient...
