生长因子对骨骼肌损伤与修复的作用

BACKGROUND: Growth factors involved in the regulation of cellular processes play an important role in the wound healing and tissue regeneration. OBJECTIVE:To elaborate the role of a variety of cellular processes involving growth factors in the repair of skeletal muscle injury, and to provide the references for the treatment and rehabilitation strategies, and the synthesis of biomaterials with growth factor for the skeletal muscle after injury. METHODS: A computer-based online search was conducted in PubMed, Mendeley, Google Scholar, and CNKI databases from 1995 to November 2015 to screen the relevant literatures using the keywords “skeletal muscle, damage repair, insulin-like growth factor, epidermal growth factor, growth factor”. Data screening, processing, and summary were performed. RESULTS AND CONCLUSION: Fifty-one eligible literatures were included. Exercise training promotes the repair and regeneration of the injured skeletal muscle cells and the recovery of the function by activating satellite cells in the sarcolemma and basement membrane to produce the numerous myoblasts. The repair involves the complex biological process regulated by growth factors. Exogenous growth factors up-regulate the mRNA expression of endogenous growth factors, stimulate the proliferation of the myoblasts, accelerate the fusion between myotubes and muscle fibers, promote the repair of skeletal muscle injury, inhibit the formation of scars, thereby enhancing the healing quality. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

细胞因子对骨骼肌细胞和胰岛β细胞的作用

BACKGROUND: A variety of cytokines such as cytokines, growth factors and inflammatory proteins play an important role in the development of skeletal muscle. OBJECTIVE:To investigate the biological characteristics of a variety of cytokines and their effects on skeletal muscle cells and pancreatic β cells. METHODS: Relevant articles published from 2002 to 2015 were retrieved in CNKI and PubMed databases using the English keywords “cytokines, adiponectin, leptin, visfatin, skeletal muscle cells, pancreatic β cells”. Initially 253 literatures were obtained, and finally 53 eligible literatures were included based on the exclusion criteria. RESULTS AND CONCLUSION: As a fat-specific protein newly found, adiponectin can improve the insulin sensitivity by promoting glucose uptake, storage and utilization in skeletal muscle cells. The activation of muscle satellite cells and skeletal myoblast proliferation are both dependent on leptin, so leptin plays a vital role in the skeletal muscle cell growth and development. Visfatin, a pleiotropic cytokine, widely presents in the skeletal muscle, liver and bone marrow, and participates in the regulation of inflammation and immune function. Furthermore, visfatin contributes to glucose uptake and metabolism in the skeletal muscle, and makes considerable effects on the stress and signal transduction of skeletal muscle cells. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

骨骼肌减少症与运动训练对肌卫星细胞影响的研究现状及展望

BACKGROUND: The phenomenon of atrophy or reduction of muscle, causing degenerative changes of muscle functions, appears along with age. Sports training, in which muscle satellite cells are of great importance, is beneficial to increase in muscle mass and improvement of muscle function.  OBJECTIVE:To summarize regulatory mechanism of satellite cells in skeletal muscle mass; changes of satellite muscle cells in the degenerative process of muscle mass and strength; declining and reverse effects of sports training intervention; situations and problems of current research and prospective of the future.  METHODS: A computer-based online search was conducted in PubMed database by using the key words of “sarcopenia, skeletal muscle, satellite cells” from 1986 to 2015. The language was limited to English. The eligible papers were further analyzed and reviewed. RESULTS AND CONCLUSION: A total of 168 papers were screened. Finally, 39 papers were selected according to the titles and objectives. Skeletal muscle atrophy is shown as II type muscle fiber atrophy, and the II type muscle fiber satellite cell content decreases simultaneously. Exercise is beneficial to increase muscle mass and improve muscle function in older people. Both resistance and endurance trainings can increase the skeletal muscle, especially the II muscle fiber satellite cell content with a further increase in the satellite cell activation and proliferation. The number and activation degree of satellite cells are related to muscle aging, and satellite cells and proliferation factors regulate muscle cell formation. Therefore, future researches should not only focus on the increase of satellite cell bank, but also explore effective ways to promote the activation of satellite cells, such as exercise training, nutrition and drugs. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

少肌症对骨骼肌的影响、分子机制及其防治

BACKGROUND: There is an urgent need to explore the loss of skeletal muscle mass during aging (sarcopenia), and its molecular mechanisms of action, and prevention and treatment strategies. OBJECTIVE: To summarize the latest progress in molecular mechanisms of sarcopenia, and to provide a fundamental for promoting functional recovery and regeneration of skeletal muscle. METHODS: A computer-based online search was conducted in PubMed and Wanfang databases from 2005 to 2015 to screen the relevant literatures using Chinese and English key words “sarcopenia, skeletal muscle, mechanism, therapy”, respectively. Consequently, 31 eligible literatures were collected, summarized, and analyzed. RESULTS AND CONCLUSION:Sarcopenia is closely correlated with oxidative stress caused by mitochondrial respiratory failure, inhibition of activating factors for regulating satellite cells, reduction in insulin secretion, decreased sensitivity, protein synthesis, and low protein diet. There are common features and molecular mechanisms in sarcopenia and disuse muscle atrophy. Further exploration of exercise and diet strategies for the treatment of sarcopenia is required. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

运动诱导骨骼肌线粒体生成中沉默信息调节因子1的作用

BACKGROUND:Silent information regulator factor-1 is an energy metabolism regulator newly received attention in sports science, which playing roles in skeletal exercise-induced muscle mitochondrial biogenesis with other regulatory factors. OBJECTIVE:To review the effect and mechanism of silent information regulator factor-1 on skeletal muscle mitochondrial biogenesis in exercise. METHODS: The PubMed database and Highwire database were retrieved with computer for the articles on exercise, silent information regulator factor-1 and skeletal muscle mitochondrial biogenesis from January 2000 to January 2013 with the key words of “SIRT1, AMPK, PGC-1α, mitochondrial biogenesis, skeletal muscle, exercise” in English. After primary search, the articles about the association between silent information regulator factor-1 and skeletal muscle mitochondrial biogenesis in exercise were selected. Articles on repeated experiment were excluded. RESULTS AND CONCLUSION:Totally 165 relevant articles were selected, and articles on repetitive research were excluded, so finaly 62 articles were included. As a NAD+-depended deacetylase, silent information regulator factor-1 induced skeletal muscle mitochondrial biogenesis by up-regulated peroxisome proliferator-activated receptor coactivator after activated during exercise. The molecular mechanism involved adenosine monophosphate-activated protein kinase and hypoxia-inducible factor 2α. In recent years, the effect of silent information regulator factor-1 on skeletal muscle mitochondrial biogenesis was doubt, the researchers though that silent information regulator factor-1 was not required for exercise-induced muscle mitochondrial biogenesis.Silent information regulator factor-1 plays an important role in exercise-induced muscle mitochondrial biogenesis. But protein and activity detection methods are different in experimental results.     

神经细胞分泌因子促进骨骼肌细胞生长

BACKGROUND: There is no effective treatment for muscle atrophy caused by peripheral nerve damage. Skeletal muscle cells, a structural unit of muscle contraction, can be used for studies on muscle atrophy when cultured in vitro. OBJECTIVE: To investigate the promotion effect of neuron-secreted factors on the growth of skeletal muscle cells in vitro. METHODS: Skeletal muscle cells primary cultured in vitro were divided into two groups: experimental group with neuron-secreted factors, and control group with common culture medium, respectively. Afterwards, the number of skeletal muscle cells and expression level of alpha actin were detected by hematoxylin-eosin staining and immunohistochemical staining, respectively. RESULTS AND CONCLUSION:The number of skeletal muscle cells and expression level of alpha actin in the experimental group were significantly higher than those in the control group (P < 0.05). In conclusion, neuron-secreted factors have the ability of promoting the growth of skeletal muscle cells and may be helpful for denervated muscle atrophy. Subject headings: Tissue Engineering; Satellite Cells, Skeletal Muscle; Actinin; Neurons; Cells, Cultured 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

转化生长因子β信号与肌肉调控

BACKGROUND: Transforming growth factor-β signaling widely existing in cells mediates cell growth, proliferation, migration, differentiation, and apoptosis. The activation of transforming growth factor-β signaling can result in muscular dystrophy. However, there have been some contradictions regarding the effects of the transforming growth factor-β signaling on muscular dystrophy. OBJECTIVE: To summarize the latest progress in the effects of the transforming growth factor-β signaling on muscle mass and function regulation to provide the solutions for the treatment of muscular dystrophy. METHODS: A computer-based online search was conducted in PubMed and Wanfang databases from 2005 to 2015 to screen the relevant literatures using Chinese and English key words “transforming growth factor-β, muscle, regulation mechanism, treatment”. A total of 102 literatures were retrieved, and 22 eligible literatures were included, summarized, and analyzed. RESULTS AND CONCLUSION: The activation of transforming growth factor-β signaling as a common cause of most muscle disorders promotes the activation of muscle satellite cells, differentiation of myocytes, myoblast infusion, the expression of muscle-specific proteins, and the inhibition of collagen synthesis, which facilitates muscular fibrosis and scar formation. Transforming growth factor-β signaling is involved in Duchenne muscular dystrophy, spinal scoliosis, type I diabetes induced skeletal muscle regenerative disorders, myocardial and cardiac remodeling. The inhibition of transforming growth factor-β signaling may result in incomplete muscle recovery. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

20 W微波照射骨骼肌卫星细胞的增殖与分化：兔骨折内固定模型研究

BACKGROUND:Low power microwave irradiation has been shown to promote the healing of fractures with internal fixation; however, its action mechanisms on the skeletal muscle around the fracture site are unclear. OBJECTIVE:To study the effects of low power microwave irradiation (20 W) on the proliferation ability of skeletal muscle satellite cells in a rabbit model of femoral fracture with internal fixation. METHODS:Forty male New Zealand rabbits were used to establish femoral fracture followed by internal fixation models, and then were equally randomized into spontaneous recovery and microwave treatment groups. Low power microwave irradiation (20 W) was given for 30 consecutive days in the microwave treatment group on day 4 after modeling, while no microwave irradiation was given in the spontaneous recovery group. Rabbit thigh muscles adjacent to the implant were obtained to isolate skeletal muscle satellite cells. Immunohistochemical staining, hematoxylin-eosin staining and quantitative RT-PCR were used to evaluate the ability of the proliferation and differentiation of skeletal muscle satellite cells. RESULTS AND CONCLUSON: Hematoxylin-eosin staining showed that there was no significant difference in the morphology and histology of skeletal muscle tissues between the spontaneous recovery and microwave treatment groups. However, the relative mRNA expression of MyoG in the cultured skeletal muscle satellite cells in vitro and the number of α-sarcometric actin-postive cells in the microwave treatment group were significantly increased compared with the spontaneous recovery group (P < 0.05). The proliferative ability of skeletal muscle satellite cells was inhibited at the early stage, but not at the later stage. Our results suggest that low power microwave irradiation (20 W) can promote the proliferation and differentiation of skeletal muscle satellite cells around the implant in a rabbit model of femoral fracture with internal fixation, and thereby confirm the efficacy and safety of low power microwave irradiation for the internal fixation of fractures. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

Application of concentrated growth factor and epidermal growth factor in the field of oral and maxillofacial soft and hard tissue injury repair北大核心

BACKGROUND: Oral and maxillofacial region is a sensitive part of beauty in appearance, and its damage often involves both soft and hard tissues. Concentrated growth factor and recombinant human epidermal growth factor can promote the repair and regeneration of local soft and hard tissue injury, which has become a new research hotspot in recent years. OBJECTIVE: To review the research progress and application of concentrated growth factor and recombinant human epidermal growth factor in the repair of soft and hard tissue injury in oral and maxillofacial region, and discuss the limitations of current research and the possibility of their combined application in the future. METHODS: The English search terms were “CGF, concentrated growth factor, rhEGF, recombinant human epidermal growth factor, tissue regeneration” and the Chinese search terms were “concentrated growth factor, epidermal growth factor, tissue engineering, tissue regeneration, oral and maxillofacial region”. Relevant articles about concentrated growth factor and recombinant human epidermal growth factor were searched in CNKI and PubMed databases. The retrieval time was from 2011 to 2021. Finally, 63 articles were selected. RESULTS AND CONCLUSION: (1) In this paper, the biological characteristics and sources of concentrated growth factor and recombinant human epidermal growth factor were briefly introduced. The research progress and clinical application status of concentrated growth factor and recombinant human epidermal growth factor in promoting the proliferation and differentiation of stem cells related to the regeneration of soft and hard tissues in oral and maxillofacial regions were emphatically summarized. The limitations of current research and possible application directions in the future were discussed. (2) Concentrated growth factor contains a variety of growth factors and CD34+ cells, which can promote the growth, proliferation, migration and differentiation of a variety of tissue cells, especially stem cells, and play an important role in tissue injury repair. (3) Concentrated growth factor is widely used in implant surgery, autologous tooth transplantation, jaw cyst resection, gingival surgery, debridement and suture, which can relieve pain, reduce inflammation, and improve postoperative bone regeneration effect and aesthetic effect. (4) Recombinant human epidermal growth factor has a great development space in soft tissue and nerve regeneration. It has been proven that recombinant human epidermal growth factor can promote a variety of stem cells to differentiate into neuron-like cells, and also induce adipocytes to differentiate into epidermal cells. Most clinical studies suggest that recombinant human epidermal growth factor can promote healing of oral ulcers and reduce scar formation. (5) “Concentrated growth factor + recombinant human epidermal growth factor” combined with adipose-derived stem cells and other stem cells that can be easily obtained have the possibility of directional formation of oral and maxillofacial soft and hard tissue. In the future, it may fill the deep oral and maxillofacial tissue defects caused by trauma, tumor resection, and promote the repair and regeneration of damaged nerves. (6) Trying to use “concentrated growth factor + recombinant human epidermal growth factor” for refractory oral ulcers, periodontal surgery, dental implants, oral and maxillofacial trauma surgery is also a new way to improve oral and maxillofacial function and appearance. Collagen sponge and chitosan membrane may be used as carriers of “concentrated growth factor + recombinant human epidermal growth factor” to facilitate shaping and prolong the action time of the composite. © 2023, Publishing House of Chinese Journal of Tissue Engineering Research. All rights reserved.     

转化生长因子-β在哮喘气道炎症与重塑中的作用

Transforming growth factor-β(TGF-β) was reported to be increased in asthma in some studies. Accumulation of TGF-β in airway promotes smooth muscle cell mitogenesis and hyperplasia, and in-duces fibroblast and myofibroblast and smooth muscle proliferation as well as increase in protein synthesis in connective tissue(such as collagen deposition on the reticular basement membrane). The autocrine induction of collagen expression by smooth muscle may contribute to the thickening of the reticular basement membrane, irre-versible f‘throsis and remodeling seen in the airways in some asthmatics. TGF-β is considered to be a major fi-brogenic cytokine. It can increase smooth muscle mass and lead to severe bronchial obstruction in an asthma at-tack.     

Tumors of skeletal muscle

The most common tumors arising in muscle are soft tissue sarcomas, fibromatoses, and hemangiomas. Rhabdomyosarcoma is primarily a tumor of childhood and adolescence and arises most commonly in extramuscular sites. Most intramuscular rhabdomyosarcomas are alveolar. Increased diagnostic accuracy and the recognition of malignant fibrous histiocytoma have changed understanding of adult, intramuscular, pleomorphic rhabdomyosarcoma. Immunohistochemistry is playing an increasingly important role in the diagnosis of rhabdomyosarcoma, and the correlation between the histologic features and clinical behavior of rhabdomyosarcoma is under investigation. Because of their diversity and overlapping histologic features, muscle tumors are a challenge for the pathologist and require intensive study by current techniques.     

Denervated frog skeletal muscle

The effects of denervation on several mechanical and electrical parameters of frog sartorius muscle have been investigated. In denervated muscles, there is no change in the resting potential and a relatively small change in the action potential. The first alteration in the action potential is a reduction of about 30% in the maximum rate of repolarization in muscles that have been denervated for 40 days or longer. Later, the overshoot and maximum rate of depolarization also decline. No tetrodotoxin resistant action potentials could be detected. Fibrillatory potentials were observed infrequently and in most cases in depolarized fibers. Twitch tension is significantly reduced by denervation while the tetanus tension is practically unaffected by denervation. The experiments suggest that the decline in twitch tension produced by denervation reflect a defect in some step of the excitation contraction coupling sequence. On the other hand, post-tetanic potentiation of the twitch is much larger in denervated than in control muscles. This potentiation in denervated muscles is paralleled by an increased action potential duration which returns to its pretetanic duration with a time course indistinguishable from that of the twitch potentiation.     

Inherited skeletal muscle disorders

The field of inherited skeletal muscle disease research has advanced rapidly since the identification of mutations in the dystrophin gene as the cause of Duchenne muscular dystrophy in 1987. From that point, an ever-increasing number of the genes associated with inherited muscle diseases have been identified. These discoveries have led to much more accurate diagnosis of the individual diseases and have allowed prenatal diagnosis where this was not previously possible. The major challenges for the future are to understand the pathophysiology of the diseases, now that the genes are being identified, and then to develop successful therapies.