针刺诱导胶原信号变化对骨骼肌损伤的修复作用

背景：根据既有研究表明,胶原纤维走向与经穴密切相关,而每个细胞至少存在两根胶原纤维以保持连接性,因此有学者推测它是人体能量传递的信号通路。目的：以经穴胶原通路假说为依据,观察胶原信号变化对骨骼肌损伤的影响,并证明电针对胶原信号的干涉作用是其促进骨骼肌修复的基本机制。方法：雄性SD大鼠按随机化原则分为3组：对照组为空白对照;模型组应用重力化打击法造备骨骼肌损伤模型;治疗组造模后采用G6850电针刺激双侧足三里穴进行干预。结果与结论：治疗组穴位区Ⅰ型胶原纤维mRNA表达量和羟脯氨酸水平低于对照组（P〈0.05）,其变化趋势较模型组更为平稳;治疗组血清肌酸激酶水平在治疗第7天就达到正常水平,治疗组穴位区Ⅰ型胶原纤维对比血清肌酸激酶呈现正相关。提示针刺后穴位区的Ⅰ型胶原纤维和羟脯氨酸可能在骨骼肌损伤修复中起到关键作用,从而引导了针刺信号的传输与转换过程,而且此信号传播过程始终与骨骼肌修复的核心指标肌酸激酶呈现高度正相关。     

Macrophage colony stimulating factor-induced macrophage differentiation influences myotube elongation

Background:Unaccustomed exercise, high-intensity dynamic sports activities, or the resumption of normal weight-bearing after a period of disuse can induce skeletal muscle injury, which activates an inflammatory response followed by muscle regeneration. Specific subsets of macrophages are involved in muscle regeneration. But the exact role of macrophage differentiation during muscle regeneration remains to be elucidated.Objective:The objective of the study was to examine the effect of macrophage colony stimulating factor (M-CSF)-differentiated, lipopolysaccharides (LPS)-stimulated-macrophage-conditioned medium on muscle-cell proliferation, fusion, and elongation, which are key events during muscle regeneration and myogenesis.Method:Murine C2C12 myoblasts were cultured in conditioned medium obtained from PU5-1R macrophages that were (a) undifferentiated, unstimulated; (b) M-CSF-differentiated, unstimulated; (c) undifferentiated, LPS-stimulated; or (d) M-CSF-differentiated, LPS-stimulated. Myoblast proliferation ratio, nuclei number, and length were measured.Results:C2C12 cells cultured in conditioned medium from M-CSF-differentiated, LPS-stimulated macrophages had significantly more nuclei and greater length than cells cultured in conditioned medium from undifferentiated, LPS-stimulated macrophages. Dilution and denaturization of the M-CSF-differentiated, LPS-stimulated-macrophage medium prevented a marked increase in C2C12 nuclei number and length. However, the C2C12 myoblast proliferation ratio was significantly greater in conditioned medium from undifferentiated, LPS-stimulated macrophages than in conditioned medium from M-CSF-differentiated, LPS-stimulated macrophages.Conclusions:M-CSF-differentiated, LPS-stimulated macrophages may influence myogenesis and the early and terminal stages of muscle regeneration. This knowledge may aid in developing therapies that will directly expedite muscle repair and lead to faster rehabilitation and reduced rehabilitation costs.     

骨骼肌钝挫伤的损伤与修复机制研究进展CSCD

总结骨骼肌钝挫伤的损伤与修复机制,并从肌卫星细胞增殖和分化学说、Ca^(2+)介导的细胞膜修复学说、内质网应激学说以及自噬学说等方面进行阐述。肌再生依赖于周围卫星细胞的分化、增殖来促进骨骼肌再生,从而修复受损肌肉的功能。调控肌卫星细胞成肌分化的相关信号通路主要包括RBP-Jκ/Notch信号、Wnt信号和P13K/Akt/mTOR信号通路。其中Notch信号通路通过调控肌卫星细胞自我更新和分化来维持肌干细胞的稳态。P13K/Akt/mTOR信号通路对肌卫星细胞的成肌分化具有正向调控作用,能够促进骨骼肌再生。然而,当前的研究对Wnt信号通路在成熟骨骼肌再生过程中的作用存在争议,激活Wnt信号通路是否有利于骨骼肌损伤与修复需要更多的研究来进行论证。Ca^(2+)介导细胞膜修复对骨骼肌钝挫伤后肌膜修复、细胞存活至关重要。但是骨骼肌损伤后引起钙泵结构受损或功能下降使Ca^(2+)回收受阻,Ca^(2+)失调通过促进线粒体的活性氧(ROS)的产生和扰乱内质网腔内的蛋白质折叠,有助于异常的蛋白质生成,内质网中异常折叠蛋白生成增多,超过其阈值并发生聚集、滞留,最终诱导内质网过度应激。内质网过度应激可通过PKC或FAM134B途径介导细胞自噬,自噬通过自我降解异常细胞器或错误折叠蛋白,以更新并维持细胞内环境稳态。关于自噬在骨骼肌损伤修复中的作用机制,除了内质网过度应激诱导,有关报道认为钝挫伤诱发的局部组织供氧不足,促使大量的ROS产生或AMPK信号通路的激活,均可诱导线粒体自噬而维持线粒体的稳定,减少能量消耗,从而有利于促进钝挫伤修复。虽然骨骼肌钝挫伤的损伤修复的机制错综复杂,但上述学说之间有交叉之处,因此对于骨骼肌钝挫伤的损伤修复机制研究可以围绕以上学说进一步深入研究,以明确不同学说在骨骼肌损伤修复的不同阶段如何发挥协同作用。     

Clinical Nursing Implications for the Recovery of Atrophied Skeletal Muscle Following Bed Rest

Atrophied skeletal muscle is a common clinical manifestation of bed rest that occurs primarily because of a lack of weight-bearing activity on the muscle. Findings from several studies using an animal model to simulate the effects of bed rest on muscles indicate that when atrophied muscle is used again for weight-bearing activity, it undergoes a series of physiological changes, such as muscle fiber (myofiber) damage, death, and regeneration. Also, in the recovering muscle, the inflammatory white blood cells, called macrophages, accumulate and shift in type in relation to the ongoing myofiber changes. Similar processes may occur in the muscles of a patient resuming normal physical activity following bed rest. The authors briefly describe the physiological changes related to atrophied muscle recovery and the implications for nursing care. Nursing measures for the recovery period may include (a) assessing for symptoms associated with muscle injury, decreased strength, and fatigue; (b) encouraging sufficient protein intake and maintaining normal metabolic demands to ensure muscle repair; and (c) temporarily avoiding the use of immunosuppressive therapy, if possible, to ensure adequate macrophage function.     

Macrophage diversity in renal injury and repair

Monocyte-derived macrophages can determine the outcome of the immune response and whether this response contributes to tissue repair or mediates tissue destruction. In addition to their important role in immune-mediated renal disease and host defense, macrophages play a fundamental role in tissue remodeling during embryonic development, acquired kidney disease, and renal allograft responses. This review summarizes macrophage phenotype and function in the orchestration of kidney repair and replacement of specialized renal cells following injury. Recent advances in our understanding of macrophage heterogeneity in response to their microenvironment raise new and exciting therapeutic possibilities to attenuate or conceivably reverse progressive renal disease in the context of fibrosis. Furthermore, parallels with pathological processes in many other organs also exist.     

高迁移率族蛋白B1在缺血性脑卒中的作用及研究进展

脑卒中后预后很大程度受炎症的影响,高迁移率族蛋白B1(HMGB1)作为促炎因子,参与了神经系统疾病的发生发展,其中在缺血性脑卒中,HMGB1贯穿动脉粥样硬化形成、脑卒中发生、脑卒中修复整个过程,并扮演着了不同的角色。HMGB1通过增加内皮通透性,促炎作用以及促进平滑肌迁移等参与了动脉粥样硬化发展。坏死神经元释放的HMGB1不仅反向导致神经元的坏死,并且作为危险相关分子模式(DAMP)分子放大炎症反应。然而星形胶质细胞通过释放HMGB1增加内源性内皮组细胞(EPCs)的活力,促进脑卒中后的神经血管修复。笔者就HMGB1的结构、功能以及缺血性脑卒中的作用及研究进展做一综述。     

Proinflammatory Macrophages Enhance the Regenerative Capacity of Human Myoblasts by Modifying Their Kinetics of Proliferation and Differentiation

Macrophages have been shown to be essential for muscle repair by delivering trophic cues to growing skeletal muscle precursors and young fibers. Here, we investigated whether human macrophages, either proinflammatory or anti-inflammatory, coinjected with human myoblasts into regenerating muscle of Rag2^−/− γC^−/− immunodeficient mice, could modify in vivo the kinetics of proliferation and differentiation of the transplanted human myogenic precursors. Our results clearly show that proinflammatory macrophages improve in vivo the participation of injected myoblasts to host muscle regeneration, extending the window of proliferation, increasing migration, and delaying differentiation. Interestingly, immunostaining of transplanted proinflammatory macrophages at different time points strongly suggests that these cells are able to switch to an anti-inflammatory phenotype in vivo, which then may stimulate differentiation during muscle regeneration. Conceptually, our data provide for the first time in vivo evidence strongly suggesting that proinflammatory macrophages play a supportive role in the regulation of myoblast behavior after transplantation into preinjured muscle, and could thus potentially optimize transplantation of myogenic progenitors in the context of cell therapy.     

Inflammation in the vascular bed: importance of vitamin C

Despite decreases in atherosclerotic coronary vascular disease over the last several decades, atherosclerosis remains a major cause of mortality in developed nations. One possible contributor to this residual risk is oxidant stress, which is generated by the inflammatory response of atherosclerosis. Although there is a wealth of in vitro, cellular, and animal data supporting a protective role for antioxidant vitamins and nutrients in the atherosclerotic process, the best clinical trials have been negative. This may be due to the fact that antioxidant therapies are applied "too little and too late." This review considers the role of vitamin C, or ascorbic acid in preventing the earliest inflammatory changes in atherosclerosis. It focuses on the three major vascular cell types involved in atherosclerosis: endothelial cells, vascular smooth muscle cells, and macrophages. Ascorbate chemistry, recycling, and function are described for these cell types, with emphasis on whether and how the vitamin might affect the inflammatory process. For endothelial cells, ascorbate helps to prevent endothelial dysfunction, stimulates type IV collagen synthesis, and enhances cell proliferation. For vascular smooth muscle cells, ascorbate inhibits dedifferentiation, recruitment, and proliferation in areas of vascular damage. For macrophages, ascorbate decreases oxidant stress related to their activation, decreases uptake and degradation of oxidized LDL in some studies, and enhances several aspects of their function. Although further studies of ascorbate function in these cell types and in novel animal models are needed, available evidence generally supports a salutary role for this vitamin in ameliorating the earliest stages of atherosclerosis.     

IRE1α regulates skeletal muscle regeneration through myostatin mRNA decay

Skeletal muscle can undergo a regenerative process in response to injury or disease to preserve muscle mass and function, which are critically influenced by cellular stress responses. Inositol-requiring enzyme 1 (IRE1) is an ancient endoplasmic reticulum stress sensor and mediates a key branch of the unfolded protein response. In mammals, IRE1α is implicated in the homeostatic control of stress responses during tissue injury and regeneration. Here, we show that IRE1α serves as a myogenic regulator in skeletal muscle regeneration in response to injury and muscular dystrophy. We found in mice that IRE1α was activated during injury-induced muscle regeneration, and muscle-specific IRE1α ablation resulted in impaired regeneration upon cardiotoxin-induced injury. Gain- and loss-of-function studies in myocytes demonstrated that IRE1α acts to sustain both differentiation in myoblasts and hypertrophy in myotubes through regulated IRE1-dependent decay (RIDD) of mRNA encoding myostatin, a key negative regulator of muscle repair and growth. Furthermore, in the mouse model of Duchenne muscular dystrophy, loss of muscle IRE1α resulted in augmented myostatin signaling and exacerbated the dystrophic phenotypes. These results reveal a pivotal role for the RIDD output of IRE1α in muscle regeneration, offering insight into potential therapeutic strategies for muscle loss diseases.     

Is loaded breathing an inflammatory stimulus?

PURPOSE OF REVIEW: To summarize recent data indicating that loaded breathing generates an inflammatory response. RECENT FINDINGS: Loaded breathing initiates an inflammatory response consisting of elevation of plasma cytokines and recruitment and activation of lymphocyte subpopulations. These cytokines do not originate from monocytes but are instead produced within the diaphragm secondary to the increased muscle activation. Oxidative stress is a major stimulus for the cytokine induction secondary to loaded breathing. The production of cytokines within the diaphragm may mediate the diaphragm muscle fiber injury that occurs with strenuous contractions, or contribute to the expected repair process. These cytokines may also compromise diaphragmatic contractility or contribute to the development of muscle cachexia. They may also have systemic effects, mobilizing glucose from the liver and free fatty acids from the adipose tissue to the strenuously working respiratory muscles. At the same time, they stimulate the hypothalamic-pituitary-adrenal axis, leading to the production of adrenocorticotropic hormone and beta-endorphins. The adrenocorticotropic hormone response may represent an attempt of the organism to reduce the injury occurring in the respiratory muscles through the production of glucocorticoids and the induction of the acute-phase response proteins. The beta-endorphin response would decrease the activation of the respiratory muscles and change the pattern of breathing, which becomes more rapid and shallow, possibly in an attempt to reduce and/or prevent further injury to the respiratory muscles. SUMMARY: Loaded breathing is an immune challenge for the body, initiating an inflammatory response. Further studies are needed to elucidate the role of this response in the development of ventilatory failure.     

Targeted expression of IL-11 in the murine airway causes lymphocytic inflammation, bronchial remodeling, and airways obstruction.

Interleukin-11 is a pleotropic cytokine produced by lung stromal cells in response to respiratory viruses, cytokines, and histamine. To further define its potential effector functions, the Clara cell 10-kD protein promoter was used to express IL-11 and the airways of the resulting transgene mice were characterized. In contrast to transgene (-) littermates, the airways of IL-11 transgene (+) animals manifest nodular peribronchiolar mononuclear cell infiltrates and impressive airways remodeling with subepithelial fibrosis. The inflammatory foci contained large numbers of B220(+) and MHC Class II(+) cells and lesser numbers of CD3(+), CD4(+), and CD8(+) cells. The fibrotic response contained increased amounts of types III and I collagen, increased numbers of alpha smooth muscle actin and desmin-containing cells and a spectrum of stromal elements including fibroblasts, myofibroblasts, and smooth muscle cells. Physiologic evaluation also demonstrated that 2-mo-old transgene (+) mice had increased airways resistance and non-specific airways hyperresponsiveness to methacholine when compared with their transgene (-) littermates. These studies demonstrate that the targeted expression of IL-11 in the mouse airway causes a B and T cell-predominant inflammatory response, airway remodeling with increased types III and I collagen, the local accumulation of fibroblasts, myofibroblasts, and myocytes, and obstructive physiologic dysregulation. IL-11 may play an important role in the inflammatory and fibrotic responses in viral and/or nonviral human airway disorders.     

高迁移率族蛋白B1在创伤免疫功能紊乱中的作用及其调节机制

OBJECTIVE: To investigate the potential effect of high mobility group box 1 protein (HMGB1) on host immune response and its molecular regulation mechanism as well as its interventional pathway following major burns/trauma. METHODS: With both animal experiments and clinical investigation, serial studies were conducted to observe the effects of HMGB1 on changes in immune function of T lymphocytes, dendritic cells, and macrophages both in vivo and in vitro. RESULTS: It was found that thermal injury or trauma induced a delayed and persistent increase in HMGB1 expression as well as its release in various tissues. HMGB1 formation could markedly influence the cell-mediated immunity, including the changes in T lymphocytes, dendritic cells, and macrophages following major trauma or burns. These effects were closely related with dysfunction of various organs in the course of sepsis. CONCLUSION: These data proved that HMGB1 not only acts as a novel "late" inflammatory mediator but is also closely associated with immunosuppression after acute insults. HMGB1 might play an important role in inducing systemic inflammatory response together with host immunological dissonance, resulting in the development of septic complications. Intervention of HMGB1 expression and release presumably provides a potentially effective way to regulate both excessive inflammatory and immune response, thereby as a measure to improve the prognosis of severe sepsis secondary to major trauma.     

Role of intestinal subepithelial myofibroblasts in inflammation and regenerative response in the gut

Inflammatory bowel disease (IBD) is characterized by an ongoing mucosal inflammation caused by a dysfunctional host immune response to commensal microbiota and dietary factors. In the pathophysiology of IBD, mesenchymal cells such as intestinal subepithelial myofibroblasts (ISEMF) affect the recruitment, retention and activation of immune cells. Mesenchymal cells also promote resolution of inflammatory activity accompanied with balanced repair processes. The transient appearance of mesenchymal cells is a feature of normal wound healing, but the persistence of these cells is associated with tissue fibrosis. Recent studies suggest that mesenchymal cells derived from bone marrow (BM) stem cells play a crucial role in intestinal repair and fibrosis. This article focuses on recent knowledge about ISEMF in the field of immune response inflammation and repair. Two major topics were documented: interaction between interleukin (IL)-17-secreting CD4+ cells (Th-17 cells) and about role of BM-derived stem cells in mucosal regenerative response via differentiation to ISEMF. Recent therapeutic strategies targeting BM stem cells for IBD patients were also documented.     

Basement Membrane and Repair of Injury to Peripheral Nerve: Defining a Potential Role for Macrophages, Matrix Metalloproteinases, and Tissue Inhibitor of Metalloproteinases-1

Injury to a peripheral nerve is followed by a remodeling process consisting of axonal degeneration and regeneration. It is not known how Schwann cell–derived basement membrane is preserved after injury or what role matrix metalloproteinases (MMPs) and their inhibitors play in axonal degeneration and regeneration. We showed that the MMPs gelatinase B (MMP-9), stromelysin-1 (MMP-3), and the tissue inhibitor of MMPs (TIMP)-1 were induced in crush and distal segments of mouse sciatic nerve after injury. TIMP-1 inhibitor activity was present in excess of proteinase activity in extracts of injured nerve. TIMP-1 protected basement membrane type IV collagen from degradation by exogenous gelatinase B in cryostat sections of nerve in vitro. In vivo, during the early phase (1 d after crush) and later phase (4 d after crush) after injury, induction of TNF-α and TGF-β1 mRNAs, known modulators of TIMP-1 expression, were paralleled by an upregulation of TIMP-1 and gelatinase B mRNAs. At 4 days after injury, TIMP-1, gelatinase B, and TNF-α mRNAs were localized to infiltrating macrophages and Schwann cells in the regions of nerve infiltrated by elicited macrophages. TIMP-1 and cytokine mRNA expression was upregulated in undamaged nerve explants incubated with medium conditioned by macrophages or containing the cytokines TGF-β1, TNF-α, and IL-1α. These results show that TIMP-1 may protect basement membrane from uncontrolled degradation after injury and that cytokines produced by macrophages may participate in the regulation of TIMP-1 levels during nerve repair.     

The discoidin domain receptor tyrosine kinase DDR1 in arterial wound repair

Collagens act as important signaling molecules regulating vascular smooth muscle cell responses during arterial wound repair. Discoidin domain receptors (DDRs) are a novel class of receptor tyrosine kinases that bind to several collagens and stimulate matrix metalloproteinase (MMP) production, but little is known about their expression and function in the vasculature. We posited a critical role for the DDRs controlling smooth muscle cell migration and proliferation and thus repair following arterial injury. Smooth muscle cells were isolated from the aortas of mice with a targeted deletion of the DDR1 gene (DDR1-null) and studied in culture using models that mimic critical steps in neointimal thickening. Our studies suggest that DDR1 plays an important role in regulating attachment to collagen, chemotaxis, proliferation, and MMP production in smooth muscle cells. Following mechanical injury to the carotid arteries, cross-sectional area of the neointima was significantly lower in DDR1-null mice than in wild-type mice. There was also a significant decrease in collagen deposition in the injured arteries of the DDR1-null mice. Our results support the hypothesis that DDR1 plays an important role as a collagen receptor, mediating intimal thickening after vascular injury.     

MIP-1alpha as a critical macrophage chemoattractant in murine wound repair.

At sites of injury, macrophages secrete growth factors and proteins that promote tissue repair. While this central role of the macrophage has been well studied, the specific stimuli that recruit macrophages into sites of injury are not well understood. This study examines the role of macrophage inflammatory protein 1alpha (MIP-1alpha), a C-C chemokine with monocyte chemoattractant capability, in excisional wound repair. Both MIP-1alpha mRNA and protein were detectable in murine wounds from 12 h through 5 d after injury. MIP-1alpha protein levels peaked 3 d after injury, coinciding with maximum macrophage infiltration. The contribution of MIP-1alpha to monocyte recruitment into wounds was assessed by treating mice with neutralizing anti-MIP-1alpha antiserum before injury. Wounds of mice treated with anti-MIP-1alpha antiserum had significantly fewer macrophages than control (41% decrease, P < 0. 01). This decrease in wound macrophages was paralleled by decreased angiogenic activity and collagen synthesis. When tested in the corneal micropocket assay, wound homogenates from mice treated with anti-MIP-1alpha contained significantly less angiogenic activity than control wound homogenates (27% positive for angiogenic activity versus 91% positive in the control group, P < 0.01). Collagen production was also significantly reduced in the wounds from anti-MIP-1alpha treated animals (29% decrease, P < 0.05). The results demonstrate that MIP-1alpha plays a critical role in macrophage recruitment into wounds, and suggest that appropriate tissue repair is dependent upon this recruitment.     

骨骼肌细胞损伤致延迟性肌肉酸痛：如何有效提高损伤肌肉恢复的速度和质量

背景：目前临床尚缺乏一种简单有效的防治延迟性肌肉酸痛的方法。目的：查阅国内外有关骨骼肌损伤及修复的相关文献,归纳总结延迟性肌肉酸痛的损伤机制和治疗方法。方法：检索1991年1月至2014年1月万方医学网和PubMed数据库的文献。英文检索词包括＂molecular mechanisms;delayed onset muscle sorenes;pain;skeletal muscle＂;中文检索词包括＂骨骼肌;损伤;延迟性肌肉酸痛;分子机制＂。纳入与骨骼肌形态结构、延迟性肌肉酸痛机制、骨骼肌治疗和修复的相关研究,阅读全文对24篇文献进行归纳分析。结果与结论：研究表明,骨骼肌损伤与钙失调、能量失调及高浓度的活性氧有关。骨骼肌性损伤包括代谢损伤、机械损伤和炎症损伤。胰岛素样生长因子、过氧化物酶体增殖物激活受体γ辅激活子1α及肿瘤坏死因子α在骨骼肌修复过程中均发挥重要作用。动物实验表明依达拉奉通过直接阻止骨骼肌中自由基的快速过氧化损伤,减少二次损伤和炎症的浸润。临床研究表明中药制剂、按摩、针灸可以延缓运动性肌肉损伤和疲劳的发生,有效提高损伤肌肉恢复的速度和质量;将理疗与中药相结合治疗延迟性肌肉酸痛可达到满意效果。