DigitalUM :: Browsing by Subject "Skeletal muscle"

Browsing by Subject "Skeletal muscle"

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Open Access
Aerobic training attenuates nicotinic acetylcholine receptor changes in the diaphragm muscle during heart failure
(F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2015) de Souza, Paula Aiello Tomé; de Souza, Rodrigo Wagner Alves; Campos Soares, Luana; Piedade, Warlen Pereira; Campos, Dijon Henrique S.; Carvalho, Robson Francisco; Padovani, Carlos Roberto; Okoshi, Katashi; Cicogna, Antônio Carlos; Michelin Matheus, Selma Maria; Dal-Pai-Silva, Maeli
Introduction: Heart failure (HF) is a progressive myopathy, with clinical signs of fatigue and limb weakness that can damage the nerve-muscle interaction, altering synaptic transmission and nicotinic acetylcholine receptors (nAChR) in neuromuscular junctions (NMJs). The diaphragm is composed of a mixed proportion of muscle fibres, and during HF, this muscle becomes slower and can alter its function. As exercise training is an accepted practice to minimise abnormalities of skeletal muscle during HF, in this study, we evaluated the hypothesis that aerobic training attenuates alterations in the expression of nAChR subunits in NMJs diaphragm during heart failure. Objective: The aim of this study was to evaluate the distribution and expression of nAChR subunits in the diaphragm muscle fibres of rats subjected to an aerobic training programme during HF. Methods: Control (Sham), control training (ShamTR), aortic stenosis (AS) and aortic stenosis training (ASTR) groups were evaluated. The expression of nAChR subunits (γ, α1, ε, β1 and δ) was determined by qRT-PCR, and NMJs were analysed using confocal microscopy. Results: We observed increased expression of the γ, α1 and β1 subunits in the AS group compared with the ASTR group. The distribution of NMJs was modulated in these groups. Discussion: HF alters the mRNA expression of nAChR subunits and the structural characteristics of diaphragm NMJs. In addition, aerobic training did notalter NMJs morphology but attenuated the alterations in heart structure and function and in nAChR subunit mRNA expression. Our findings demonstrate the beneficial effects of aerobic exercise training in maintaining the integrity of the neuromuscular system in the diaphragm muscle during HF and may be critical for non-pharmacological therapy to improve the quality of life for patients with this syndrome.
Open Access
Aging affects different human muscles in various ways. An image analysis of the histomorphometric characteristics of fiber types in human masseter and vastus lateralis muscles from young adults and the very old
(Murcia : F. Hernández, 2000) Kirkeby, S.; Garbarsch, C.
This study is an attempt to objectively evaluate age-related changes in human muscles by use of histomorphometric methods. Aging in humans induces dramatic transformations in the skeletal muscles but little is known as to whether or not the aging processes per se may affect all muscles equally. In this study aging of two human muscles with different functions, origin and nerve supply is compared. Sections were cut from masseter and vastus lateralis muscles obtained from young adults aged 18-24 years and from the very old aged 90-102 years. Muscle fiber types were classified with the traditional myofibrillar ATPase staining. Various histomorphometric parameters of the different fiber types in human masseter and vastus lateralis muscle sections were obtained by image analyses to evaluate the age-related changes in the muscle fibers. The following variables were calculated: the number of each fiber type per photographed area; the area of each fiber and two indicators for the shape of the muscle fibers. In the aging muscles there was no relative preferential loss of a fiber type. High numbers of intermediate ATPase-stained fibers (IM fibers) were found in some old vastus muscles but were only sporadic in young vastus muscles. However, there was no change in the percentage distribution of intermediate ATPasestained fibers when young and very old human masseter muscles were compared. Incubation of the sections with antimyosin antibodies showed that the IM fibers in old masseter and old vastus contained different myosin heavy chains. Thus ATPase activity and anti-myosin staining displayed a somewhat different pattern of fiber type distribution. The main changes in the shape and area indicated that type I fibers in the masseter became more circular while in the vastus they decreased significantly in size. The type I1 fibers in the vastus became very small and deviated significantly from circularity whereas the type I1 fibers in the masseter only exhibited a decrease in the size of the fibers. Histomorphometric measurements show that aging affects different human muscles in various ways.
Open Access
Analysis of neogenesis in rabbit skeletal muscles after chronic traction
(Murcia : F. Hernández, 1994) Sun, J.S.; Hou, S.M.; Liu, T,K.; Lu, K.S.
After application of a modified Orthofix mini-extraskeletal fixator, the hind limb of New Zealand White rabbits was osteotomized and then slowly lengthened at a rate of 1 mmlday. After a 20 mm gain in length, the net weight and the length of muscular and tendinous portions were measured and histological examination was carried out in triceps surae muscles. Quantitative analysis showed a significant increase in the gained length of the muscular portion (28.05% to 30.65%). Histological studies of these lengthened muscles showed a generalized increase in cellularity with scanty inflammatory cell infiltration near the myotendinous junction. The increased cellularity is due to the presence of muscle precursor cells characterized by large, oval and pale-stained vesicular nuclei and two prominent nucleoli. The nuclei of these precursor cells were larger and more numerous near the myotendinous junction, and gradually changed into a flattened and more condensed form at a distance from the junction. Occasionally, chains of centrally-located nuclei of primitive myoblasts were also visible. It is concluded that traction neogenesis of the skeletal muscle during limb lengthening does exist and occurs mainly near the myotendinous junction.
Open Access
Does coenzyme-Q have a protective effect against atorvastatin induced myopathy? A histopathological and immunohistochemical study in albino rats
(2015) Khalil, Mahmoud Salah; Khamis, Nehal; Al-drees, Abdulmajeed; Abdulghani, Hamza Mohammad
Introduction. In addition to their lipidlowering effect, statins have pleiotropic effects that may extend their use to the treatment and prevention of various other diseases such as cancer, osteoporosis, multiple sclerosis, rheumatoid arthritis, type 2 diabetes, and Alzheimer’s disease. Consequently, the number of patients taking statins is expected to increase. A side effect of statins, statin-induced myopathy, which may result from reduced muscular coenzyme Q10 levels, limits their use. The current study investigates if supplementing with CoQ10 could ameliorate statin induced myopathy. Materials and Methods. Forty adult male albino rats were randomized into 4 groups, with 10 rats per group. The following was administered to the rats using oral gavage for 4 weeks: Group 1: 2 ml of 0.5% carboxymethyl cellulose once daily. Group 2: 100 mg/kg/ day coenzyme Q10 dissolved in 2 ml of cotton seed oil. Group 3: 10 mg/kg once daily atorvastatin dissolved in 0.5% carboxymethyl cellulose. Group 4: concomitantly received CoQ10 and atorvastatin similar to groups 2 and 3 respectively. Plasma creatine kinase levels were measured by using spectrophotometer. The right extensor digitorum longus muscle sections were stained for histological (Haematoxylin & Eosin, Masson trichrome and Phosphotungstic acid haematoxylin) and immunohistochemical (cytochrome C and Bax) examinations. Quantitative measures of cytochrome C and Bax were carried out using image analyzer. Results. Atorvastatin induced increased total creatine kinase, skeletal muscle variations in the sizes and shapes, necrosis, disorganization, nuclear pyknosis, karyorrhexis, karyolysis, dismantled plasma membrane, excess collagen fibers and lipid deposition in addition to loss of cross striation. Atorvastatin increased the intensity of the immune-positive reactions of cytochrome C and Bax. These changes were ameliorated by concomitantly giving coenzyme Q10. Conclusion: CoQ10 may ameliorate atorvastatin induced skeletal muscle injury.
Open Access
Effect of endurance running on cardiac and skeletal muscle in rats
(Murcia : F. Hernández, 2001) Díaz-Herrera, P.; Torres, A.; Morcuende, J.A.; Garcia-Castellano, J.M.; Calbet, J.A.L.; Sarrat, R.
We studied the effect of resistance running on left cardiac ventricle size and rectus femoris muscle fiber composition. Ten male Wistar rats were trained on a treadmill 6 days per week for 12 weeks. Ten rats remained sedentary and served as controls. A higher endurance time (40%) and cardiac hypertrophy in the trained animals were indicators of training efficiency. Morphometric analysis of the left ventricle crosssectional area, left ventricular wall, and left ventricular cavity were evaluated. The endurance-running group demonstrated a hypertrophy of the ventricular wall (22%) and an increase in the ventricular cavity (25%); (pc0.0001). Semi-quantitative analysis of rectus femoris fiber-type composition and of the oxidative and glycolytic capacity was histochemically performed. Endurance running demonstrated a significant (pc0.01) increase in the relative frequency of 5 p e 1 (24%), Qpe IIA (8%) and 5 p e IIX (16%) oxidative fibers, and a decrease in Qpe IIB (20%) glycolytic fibers. There was a hypertrophy of both oxidative and glycolytic fiber types. The relative cross-sectional area analysis demonstrated an increase in oxidative fibers and a decrease in glycolytic fibers (p<0.0001). Changes were especially evident for 'Qpe IIX oxidative-glycolytic fibers. The results of this study indicate that the left ventricle adapts to endurance running by increasing wall thickness and enlargement of the ventricular cavity. Skeletal muscle adapts to training by increasing oxidative fiber 'Qpe. This increase may be related to fiber transformation from Qpe IIB glycolytic to Qpe IIX oxidative fibers. These results open the possibility for the use of this type of exercise to prevent muscular atrophy associated with age or post-immobilization.
Open Access
Effect of heparin and antivenom on skeletal muscle damage produced by Bothrops jararacussu venom
(Murcia : F. Hernández, 2002) Calil-Elias, S.; Martinez, A.M.B.; Melo, P.A.
We examined the effect of treatment with heparin and polyvalent antivenom on mice muscle Extensor digitorum longus (EDL) regeneration, after damage induced by injection of B o t h rops jara ra c u s s u crude venom over the muscle of the right posterior limb. The mice were separated into groups and each group received treatment, by intravenous route with either high molecular weight heparin (H), low molecular weight heparin (LMWH), polyvalent antivenom (PAV) or with the combination of PAV plus H or PAV plus LMWH at 15 minutes and 4 hours after the injection of the venom. Myotoxicity was measured by the increase in plasma creatine kinase (CK) activity at two hours after the injection of the venom. The histological changes in EDL at 1, 3, 7 and 21 days after the injection of the ve n o m were analyzed by light microscopy. In each group the normal and regenerated muscle fibers were quantifi e d using Scion Image computer program. We also evaluated in vitro, the influence of these substances in the proteolytic and phospholipase activities of the ve n o m . Heparins decreased the proteolytic activity of the venom but did not affect its phospholipase activity. However the PAV antagonized both activities. PAV and its combinations showed antimyotoxic activity, according to the magnitude of CK plasma levels. At 21 days the r egeneration was observed in all animals, also in those that received only the venom. All treatments, ex c e p t LMWH, promote a significant increase in the number of muscle fibers.
Open Access
Fiber type diversity in skeletal muscle explored by mass spectrometry-based single fiber proteomics
(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2020) Schiaffino, Stefano; Reggiani, Carlo; Murgia, Marta
Mammalian skeletal muscles are composed of a variety of muscle fibers with specialized functional properties. Slow fibers are suited for long lasting and low intensity contractile activity, while various subtypes of fast fibers are optimized to produce high force and power even with a significant fatigue. The functional specialization of muscle fibers is based on selective gene expression regulation, which provides each fiber with a specific protein complement. The recent refinement of small-scale sample preparation, combined with the development of mass spectrometers characterized by high sensitivity, sequencing speed and mass accuracy, has allowed the characterization of the proteome of single muscle fibers with an unprecedented resolution. In the last few years, the first studies on the global proteomics of individual fibers of different types have been published. In this short review we discuss the methodological advancements which have opened the way to single fiber proteomics and the discovery power of this approach. We provide examples of how specific features of single fibers can be overlooked when whole muscle or multi- fiber samples are analyzed and can only be detected when a single fiber proteome is analyzed. Thus, novel subtype-specific metabolic features, most prominently mitochondrial specialization of fiber types, have been revealed by single fiber proteomics. In the same way, specific adaptive responses of single fibers to aging or loss of neural input have been detected when single fibers were individually analyzed. We conclude that the fiber type-resolved proteomes represent a powerful tool which can be applied to a variety of physiological and pathological conditions.
Open Access
Fiber type diversity in skeletal muscle explored by mass spectrometry-based single fiber proteomics.
(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2020) Schiaffino, Stefano; Reggiani, Carlo; Murgia, Marta
Mammalian skeletal muscles are composed of a variety of muscle fibers with specialized functional properties. Slow fibers are suited for long lasting and low intensity contractile activity, while various subtypes of fast fibers are optimized to produce high force and power even with a significant fatigue. The functional specialization of muscle fibers is based on selective gene expression regulation, which provides each fiber with a specific protein complement. The recent refinement of small-scale sample preparation, combined with the development of mass spectrometers characterized by high sensitivity, sequencing speed and mass accuracy, has allowed the characterization of the proteome of single muscle fibers with an unprecedented resolution. In the last few years, the first studies on the global proteomics of individual fibers of different types have been published. In this short review we discuss the methodological advancements which have opened the way to single fiber proteomics and the discovery power of this approach. We provide examples of how specific features of single fibers can be overlooked when whole muscle or multi- fiber samples are analyzed and can only be detected when a single fiber proteome is analyzed. Thus, novel subtype-specific metabolic features, most prominently mitochondrial specialization of fiber types, have been revealed by single fiber proteomics. In the same way, specific adaptive responses of single fibers to aging or loss of neural input have been detected when single fibers were individually analyzed. We conclude that the fiber type-resolved proteomes represent a powerful tool which can be applied to a variety of physiological and pathological conditions
Open Access
Histochemical and ultrastructural study of skeletal muscle in patients with sepsis and multiple organ failure syndrome (MOFS)
(F. Hernández y Juan F. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología, 1998) Díaz, N. L.; Finol, H. J.; Torres, S. H.; Zambrano, C. I.; Adjounian, H.
Muscle biopsies for histochemical and ultrastuctural analysis were obtained from seven critically ill patients admitted to the Intensive Care Unit of the "Domingo Luciani" Hospital, Caracas, Venezuela. The sample included two patients with sepsis of abdominal origin, and five that presented sepsis/MOFS, with renal, hepatic, and respiratory disturbances and muscular weakness. Sections were examined for myosin adenosine triphosphatase (ATPase) after pre-incubation with both acid buffer (pH 4.37 and 4.6) and alkaline buffer (pH 10.3), for reduced nicotinamide dinucleotide diaphorase (NADHd), and for a-glycerophosphate dehydrogenase (a-GPDH). Sections were stained with hematoxilin and eosin to look for pathological changes and examined with a transmission electron microscope. Skeletal muscle of patients in early stage of sepsis showed a normal aspect with light microscopy, but at the ultrastructural level some of the fibres showed atrophy and some capillaries looked altered . Patients with sepsis/MOFS exhibited an evident muscle disorder with oedema. infiltrate, atrophy and segmental necrosis. All fibre types showed decrease in diameter; specially fibre types IIA and lIB . Intramuscular capillaries were thickened and occluded , indexes of capillarity were slightly reduced, and fibre oxidative activity was decreased. At ultrastructural level fibres showed severe atrophy, contractile system disorganization and segmental necrosis. Capillaries were also altered and the mononuclear cell infiltrate was abundant and represented by macrophages. lymphocytes and mastocytes.
Open Access
Histology of skeletal muscle reconstructed by means of the implantation of autologous adipose tissue: an experimental study
(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2020) Leiva Cepas, Fernando; Jimena, Ignacio; Ruz Caracuel, Ignacio; Luque, Evelio; Villalba, Rafael; Peña Amaro, Jose
The purpose of this study was to determine the histological characteristics of a skeletal muscle reconstructed by means of the implantation of autologous adipose tissue following an experimentally- induced volumetric muscle loss. A cylindrical piece in the belly of the rat anterior tibial muscle was removed. In the hole, inguinal subcutaneous adipose tissue of the same rat was grafted. Animals were sacrificed 7, 14, 21, 28 and 60 days posttransplantation. Histological, histochemical, immunohistochemical and morphometric techniques were used. At all times analyzed, the regenerative muscle fibers formed from the edges of the muscle tissue showed histological, histochemical and immunohistochemical differences in comparison with the control group. These differences are related to delays in the maturation process and are related to problems in reinnervation and disorientation of muscle fibers. The stains for MyoD and desmin showed that some myoblasts and myotubes seem to derive from the transplanted adipose tissue. After 60 days, the transplant area was 20% occupied by fibrosis and by 80% skeletal muscle. However, the neo-muscle was chaotically organized showing muscle fiber disorientation and centronucleated fibers with irregular shape and size. Our results support the hypothesis that, at least from a morphological point of view, autologous adipose tissue transplantation favors reconstruction following a volumetric loss of skeletal muscle by combining the inherent regenerative response of the organ itself and the myogenic differentiation of the stem cells present in the adipose tissue. However, in our study, the formed neo- muscle exhibited histological differences in comparison with the normal skeletal muscle
Open Access
Histopathology of Duchenne muscular dystrophy in correlation with changes in proteomic biomarkers
(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2022) Zweyer, Margit; Sabir, Hemmen; Dowling, Paul; Gargan, Stephen; Murphy, Sandra; Swandulla, Dieter; Ohlendieck, Kay
Duchenne muscular dystrophy is an inherited disorder of early childhood that affects multiple systems in the body. Besides late-onset cardio-respiratory syndrome and various body-wide pathophysiological changes, X-linked muscular dystrophy is primarily classified as a disorder of the skeletal musculature. This is reflected by severe histopathological alterations in voluntary contractile tissues, including progressive fibre degeneration, fat substitution, reactive myofibrosis and chronic inflammation. The underlying cause for dystrophinopathy are genetic abnormalities in the DMD gene, which can result in the almost complete loss of the membrane cytoskeletal protein dystrophin, which triggers the collapse of the dystrophin-associated glycoprotein complex and disintegration of sarcolemmal integrity. This in turn results in an increased frequency of membrane micro-rupturing and abnormal calcium ion fluxes through the impaired plasmalemma, which renders muscle fibres more susceptible to enhanced proteolytic degradation and necrosis. This review focuses on the complexity of skeletal muscle changes in X-linked muscular dystrophy and outlines cell biological and histological alterations in correlation to proteomewide variations as judged by mass spectrometric analyses. This includes a general outline of sample handling, subcellular fraction protocols and modern proteomic approaches using gel electrophoretic and liquid chromatographic methods for efficient protein separation prior to mass spectrometry. The proteomic profiling of the dystrophic and highly fibrotic diaphragm muscle is described as an example to swiftly identify novel proteomic markers of complex histopathological changes during skeletal muscle degeneration. The potential usefulness of new protein markers is examined in relation to key histopathological hallmarks for establishing improved diagnostic, prognostic and therapy-monitoring approaches in the field of dystrophinopathy.
Open Access
History and development of staining methods for skeletal muscle fiber types
(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2022) Sawano, Shoko; Mizunoya, Wataru
The contractile and metabolic properties of skeletal muscles depend on the composition of muscle fibers. There are two major fiber types: type 1 and type 2. Type 2 fibers are further subdivided into type 2A, 2X, and 2B fibers. Muscle fiber type composition is an important property that affects sports performance and metabolic ability in humans, and meat quality in domestic animals. In this review, we summarize the history of muscle fiber type classification based on various staining methods for skeletal muscle sections. The history illustrates the development of an experimental method to detect myosin heavy chain (MyHC) proteins, which are the most common marker molecules for muscle fiber type. Metabolic enzymes, such as nicotinamide adenine dinucleotide-tetrazolium reductase and succinate dehydrogenase are also described for histochemical staining combined with myosin ATPase staining. We found an improvement in the quality of antibodies used for immunostaining of MyHC, from polyclonal antibodies to monoclonal antibodies (mAbs) and then to mAbs produced by synthetic peptides as antigens. We believe that the information presented herein will assist researchers in selecting optimal staining methods, dependent on the experimental conditions and purposes
Open Access
Hydroxy group requirement for halofuginone-dependent inhibition of muscle fibrosis and improvement of histopathology in the mdx mouse model for Duchenne muscular dystrophy
(Universidad de Murcia. Departamento de Biología Celular e Histología, 2019) Wellner, Gili; Mordechay, Sharon; Evans, Paul; Genin, Olga; Pines, Mark; Halevy, Orna
In Duchenne muscular dystrophy (DMD), the progressive loss of muscle and its ability to function is associated with significant fibrosis, representing the major disease complication in patients. Halofuginone, a halogenated analog of the naturally occurring febrifugine, has been shown to prevent fibrosis in various animal models, including those of muscular dystrophies. Here, two optically active enantiomers of deoxyhalofuginone—a halofuginone analogue in which the hydroxy group in position 3 was removed from the piperidinyl entity—were evaluated with respect to their effect on muscle histopathology in mdx mice. Male mdx mice were treated with either deoxyhalofuginone (as single enantiomers or in racemic form), or halofuginone, for 10 weeks, starting at the age of 4 weeks. Halofuginone caused a significant reduction in total collagen content, degenerative areas, as well as in utrophin and phosphorylated-Smad3 levels in the mdx diaphragms. However, neither the deoxyhalofuginone enantiomers, nor its racemic form had any effect on these parameters. A positive effect of the deoxyhalofuginone (+)-enantiomer was observed on myofiber diameters; however, it was lesser than that of halofuginone. It is concluded that the hydroxy group plays a key role in halofuginone’s effects related to fibrosis in DMD, and points towards the transforming growth factor β/Smad3 signaling pathway being involved in this inhibition. Elucidation of the structure–function relationship of halofuginone, in relation to inhibiting fibrosis in muscular dystrophies, is of the utmost importance for creating the next generation of anti-fibrotic therapies that will be more efficacious and less toxic, hence improving life quality of patients.
Open Access
Ischemia-reperfusion of human skeletal muscle during aortoiliac surgery: effects of acetylcarnitine
(Murcia : F. Hernández, 1994) Adembri, C.; Lombardo Domenici, L.; Formigli, L.; Brunelleschi, S.; Ferrari, E.; Novelli, G.P.
Our previous study on human skeletal muscle undergoing ischemia and reperfusion has revealed that granulocytes, which infiltrate the muscle tissue in large numbers, play an important role in mediating fibre injuries by producing superoxide anion (O?) which is responsible for membrane lipid peroxidation. In the current study, five patients undergoing aortic reconstructive surgery were given acetyl-carnitine (2 mglkg i.v. plus 1 mglkglmin for 30 min) prior to the induction of ischemia. Muscle biopsies and blood samples were examined: a) after anaesthesia; b) at the end of ischemia; and c) 30 min after reperfusion, with the aim of elucidating whether acetylcarnitine could prevent the infiltration andlor the activation of granulocytes and eventually skeletal muscle injuries. During ischemia and reperfusion complement activation recmited numerous granulocytes into the muscle tissue, but, contrary to the untreated samples, the ability for O2 -generation of these cells remained at low levels and was comparable to that of ischemia even when molecular 02 was reintroduced to the tissue. Accordingly, the morphological changes of the postischemic muscle fibers were substantially reduced when compared to the untreated samples; in fact, the mitochondrial swelling was only moderate and the intramitochondrial dense bodies were small and scarce. The current findings support a positive role of acetyl-carnitine in ameliorating the ischernia-reperfusion (1-R)-induced damage of human skeletal muscle.
Open Access
Major histocompatibility complex expression in muscle of rats with graft-versus-host disease
(Murcia : F. Hernández, 1996) hba, Y.; Fujikura, Y.; Sawada, T.; Tokuda, N.; Morimatsu, M.; Fukumoto, T.
Immunohistochemical examination of rat skeletal muscle during graft-versus-host disease (GVHD), a systemic immune reaction, was performed to investigate specific immune reactivities focusing on major histocompatibility complex (MHC) expression and inflammatory cell infiltration of skeletal muscle during a systemic immune reaction. MHC class 11 expression and inflammatory cell infiltration did not increase. MHC class 1 was expressed along the contour of muscle fibres, and most strongly expressed by the cells which were distributed throughout the endomysium and perimysium. Seventy-six percent of these MHC class I+ cells carried endothelial cell-markers, while 24% of them did not. The latter cells were revealed not to be inflammatory cells such as lymphocytes, granulocytes or macrophages when examined by immunostaining using severa1 exudate-cell markers. Neither were they myosatellite cells because they were located outside the basement membrane. These results may be useful for considering animal models of inflammatory myopathies such as polymyositis and dermatomyositis.
Open Access
Maternal protein restriction changes structural and metabolic gene expression in the skeletal muscle of aging offspring rats
(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2021) Valente, Jéssica Silvino; Perez, Érika Stefani; Zanella, Bruna Tereza Thomazini; Gutierrez de Paula, Tassiana; Alcantara dos Santos, Sérgio Alexandre; Oliveira da Silva Duran, Bruno; Carvalho, Robson Francisco; Justulin, Luis Antonio; de Almeida Fantinatti, Bruno Evaristo; Dal-Pai-Silva, Maeli
Maternal protein restriction affects postnatal skeletal muscle physiology with impacts that last through senility. To investigate the morphological and molecular characteristics of skeletal muscle in aging rats subjected to maternal protein restriction, we used aged male rats (540 days old) born of dams fed a protein restricted diet (6% protein) during pregnancy and lactation. Using morphological, immunohistochemical and molecular analyses, we evaluated the soleus (SOL) and extensor digitorum longus (EDL) muscles, muscle fiber cross-sectional area (CSA) (n=8), muscle fiber frequency (n=5) and the gene expression (n=8) of the oxidative markers (succinate dehydrogenase-Sdha and citrate synthase-CS) and the glycolytic marker (lactate dehydrogenase-Ldha). Global transcriptome analysis (n=3) was also performed to identify differentially regulated genes, followed by gene expression validation (n=8). The oxidative SOL muscle displayed a decrease in muscle fiber CSA (*p<0.05) and in the expression of oxidative metabolism marker Sdha (***p<0.001), upregulation of the anabolic Igf-1 (**p<0.01), structural Chad (**p<0.01), and Fmod (*p<0.05) genes, and downregulation of the Hspb7 (**p<0.01) gene. The glycolytic EDL muscle exhibited decreased IIA (*p<0.05) and increased IIB (*p<0.05) fiber frequency, and no changes in muscle fiber CSA or in the expression of oxidative metabolism genes. In contrast, the gene expression of Chad (**p<0.01) was upregulated and the Myog (**p<0.01) gene was downregulated. Collectively, our morphological, immunohistochemical and molecular analyses showed that maternal protein restriction induced changes in the expression of metabolic, anabolic, myogenic, and structural genes, mainly in the oxidative SOL muscle, in aged offspring rats
Open Access
Mechanisms of skeletal muscle degradation and its therapy in cancer cachexia
(Murcia : F. Hernández, 2007) Melstrom, L.G.; Melstrom Jr., K.A.; Ding, X.Z.; Adrian, T.E.
Severe or chronic disease can lead to cachexia which involves weight loss and muscle wasting. Cancer cachexia contributes significantly to disease morbidity and mortality. Multiple studies have shown that the metabolic changes that occur with cancer cachexia are unique compared to that of starvation. Specifically, cancer patients seem to lose a larger proportion of skeletal muscle mass. There are three pathways that contribute to muscle protein degradation: the lysosomal system, cytosolic proteases and the ubiquitin (Ub)-proteasome pathway. The Ub-proteasome pathway seems to account for the majority of skeletal muscle degradation in cancer cachexia and is stimulated by several cytokines including tumor necrosis factor-a, interleukin-1ß, interleukin-6, interferon-g and proteolysis-inducing factor. Cachexia is particularly severe in pancreatic cancer and contributes significantly to the quality of life and mortality of these patients. Several factors contribute to weight loss in these patients, including alimentary obstruction, pain, depression, side effects of therapy and a high catabolic state. Although no single agent has proven to halt cachexia in these patients there has been some progress in the areas of nutrition with supplementation and pharmacological agents such as megesterol acetate, steroids and experimental trials targeting cytokines that stimulate the Ub-proteasome pathway.
Open Access
Muscle regeneration induced by snake venom. A histological and histochemical study
(Murcia : F. Hernández, 1989) Peña, J.; Jimena, I.; Luque, E.; Martín, J.D.; Vaamonde, R.
This report describes the regeneration pattern of anterior tibial muscle of the rat after the inoculation of the snake venom of Bothrops jararacussu . The results show that this regeneration pattern is rather similar to the pattern described in other experimental models. Three days after the injection, three differentiated areas are established: a periferic one of surviving fibres, a second one called myogenic area, and the last one, more internal, made of necrotic fibres that are phagocited by macrophages. The surface of the surviving muscle fibres has myoblasts sticking to it and five days after, the myogenic area is occupied by many of them. Both the previous phagocytosis and the myoblasts came from the area of current uninjured fibres. After 30 and 60 days the regeneration is completed and there are only a few marks that show that the regeneration has taken place.
Open Access
Muscular hypertrophy and atrophy in normal rats provoked by the administration of normal and denervated muscle extracts
(Universidad de Murcia. Departamento de Biología Celular e Histología, 2016) Agüera, Eduardo; Castilla, Salvador; Luque, Evelio; Jimena, Ignacio; Leiva Cepas, Fernando; Ruz Caracuel, Ignacio; Peña, José
This study was conducted to determine the effects of extracts obtained from both normal and denervated muscles on different muscle types. Wistar rats were used and were divided into a control group and four experimental groups. Each experimental group was treated intraperitoneally during 10 consecutive days with a different extract. These extracts were obtained from normal soleus muscle, denervated soleus, normal extensor digitorum longus, and denervated extensor digitorum longus. Following treatment, the soleus and extensor digitorum longus muscles were obtained for study under optic and transmission electron microscope; morphometric parameters and myogenic responses were also analyzed. The results demonstrated that the treatment with normal soleus muscle and denervated soleus muscle extracts provoked hypertrophy and increased myogenic activity. In contrast, treatment with extracts from the normal and denervated EDL had a different effect depending on the muscle analyzed. In the soleus muscle it provoked hypertrophy of type I fibers and increased myogenic activity, while in the extensor digitorum longus atrophy of the type II fibers was observed without changes in myogenic activity. This suggests that the muscular responses of atrophy and hypertrophy may depend on different factors related to the muscle type which could be related to innervation.
Open Access
Nitric oxide synthase in skeletal muscle fibers, a signaling component of the dystrophin-glycoprotein complex
(Murcia : F. Hernández, 1999) Grozdanovic, Z.; Baumgarten, H.G.
The present review deals with the anatomical distribution, physiological importance, and pathological implications of the neuronal-type nitric oxide synthase (nNOS) in skeletal muscle. Throughout the body, nNOS is located beneath the sarcolemma of skeletal muscle fibers. In rodents, nNOS is enriched in type IIb muscle fibers, but is more homogenously distributed among type I1 and type I fibers in humans and subhuman primates. It is accumulated on the postsynaptic membrane at the neuromuscular junction. An increased concentration of nNOS is noted at the sarcolemma of muscle spindle fibers, in particular nuclear bag fibers, which belong to type I fibers. The association of nNOS with the sarcolemma is mediated by the dystrophin-g1 ycoprotein complex. Specifically, nNOS is linked to al-syntrophin through PDZ domain interactions. Possibly, it also directly binds to dystrophin. The activity and expression of nNOS are regulated by both myogenic and neurogenic factors. Besides acetylcholine, glutamate has also been shown to stimulate nNOS, probably acting through Nmethyl- D-aspartate receptors, which are colocalized with nNOS at the junctional sarcolemma. Functional studies have implicated nitric oxide as a modulator of skeletal muscle contractility, mitochondrial respiration, carbohydrate metabolism, and neuromuscular transmission. A clinically relevant aspect of nNOS is its absence from the skeletal muscle sarcolemma of patients with Duchenne muscular dystrophy (DMD). A concept is presented which suggests that, as a consequence of the disruption of the dystrophin-glyoprotein complex in DMD, nNOS fails to become attached to the sarcolemma and is subject to downregulation in the cytosol.