Mibefradil improves skeletal muscle mass, function and structure in obese mice / 南方医科大学学报

OBJECTIVE@#To observe the effect of mibefradil on skeletal muscle mass, function and structure in obese mice.@*METHODS@#Fifteen 6-week-old C57BL/6 mice were randomized equally into normal diet group (control group), high-fat diet (HFD) group and high-fat diet +mibefradil intervention group (HFD +Mibe group). The grip strength of the mice was measured using an electronic grip strength meter, and the muscle content of the hindlimb was analyzed by X-ray absorptiometry (DXA). Triglyceride (TG) and total cholesterol (TC) levels of the mice were measured with GPO-PAP method. The cross-sectional area of the muscle fibers was observed with HE staining. The changes in the level of autophagy in the muscles were detected by Western blotting and immunofluorescence assay, and the activation of the Akt/mTOR signaling pathway was detected with Western blotting.@*RESULTS@#Compared with those in the control group, the mice in HFD group had a significantly greater body weight, lower relative grip strength, smaller average cross sectional area of the muscle fibers, and a lower hindlimb muscle ratio (P < 0.05). Immunofluorescence assay revealed a homogenous distribution of LC3 emitting light red fluorescence in the cytoplasm in the muscle cells in HFD group and HFD+Mibe group, while bright spots of red fluorescence were detected in HFD group. In HFD group, the muscular tissues of the mice showed an increased expression level of LC3 II protein with lowered expressions of p62 protein and phosphorylated AKT and mTOR (P < 0.05). Mibefradil treatment significantly reduced body weight of the mice, lowered the expression level of p62 protein, and increased forelimb grip strength, hindlimb muscle ratio, cross-sectional area of the muscle fibers, and the expression levels of LC3 II protein and phosphorylated AKT and mTOR (P < 0.05).@*CONCLUSION@#Mibefradil treatment can moderate high-fat diet-induced weight gain and improve muscle mass and function in obese mice possibly by activating AKT/mTOR signal pathway to improve lipid metabolism and inhibit obesityinduced autophagy.

The effects of exercise on the renin-angiotensin system in blood and skeletal muscle after heart failure / 中华物理医学与康复杂志

Objective:To observe the effect of exercise on the renin-angiotensin system (RAS) in the blood and skeletal muscles of rats with chronic heart failure (CHF).Methods:Fifty male Wistar rats were randomly divided into a sedentary control group, an exercise control group, a model sedentary group and a model exercise group. CHF was modelled in the rats of the model sedentary and exercise groups, while those of the sedentary and exercise control groups received a sham operation. The exercise groups performed treadmill exercise for 8 weeks (5 times per week). After the 8 weeks the activity of angiotensin-converting enzyme (ACE) and ACE2 in the plasma and soleus muscle was determined using the fluorescent substrate method. Angiotensin II (AngII) and Ang (1-7) were detected in plasma and the soleus muscle using liquid chromatography. The expression of Ang II type 1 receptor (AT1R) and Mas receptor (MasR) in skeletal muscles was detected using western blotting.Results:Compared with the sedentary control group, there was significantly increased average ACE activity and lower average ACE2 activity in the model sedentary group. There was a significant decrease in the average plasma Ang II content and ACE activity, and a significant increase in the Ang-(1-7)/Ang II ratio in the model exercise group. Compared with the model sedentary group, the average ACE activity and plasma Ang II content was significantly lower in the model exercise group but the average ACE2 activity was significantly higher. Compared with the sedentary control group, the average Ang II content and AT1R protein expression in the soleus muscles had increased significantly in the model sedentary group, and the average expression of MasR protein in the soleus muscles increased significantly in the model exercise group. However, compared with the model sedentary group, the average content of Ang II and the average expression of AT1R protein in the soleus muscles had decreased significantly in the model exercise group and the average Ang-(1-7)/Ang II ratio had increased significantly.Conclusion:Exercise can induce the conversion of RAS from ACE-Ang II-AT1R to ACE2-Ang-(1-7)-MasR after chronic heart failure, at least in rats. The changes in the components of the RAS in the plasma and skeletal muscle differ.

Body composition of women with and without dynapenia defined by different cut-off points / Composição corporal de mulheres com e sem dinapenia definida por diferentes pontos de corte

ABSTRACT Objective To compare body composition of postmenopausal women with and without dynapenia, defined by different cut-off points. Methods Body composition was assessed by electrical bioimpedance and the nutritional status by the body mass index. Dynapenia was diagnosed according to handgrip strength, using the following cut-off points: handgrip strength <16kgf and <20 kgf. Results A total of 171 women (50 to 92 years of age) participated in the investigation. The mean age of non-dynapenic and dynapenic women (handgrip strength <20kgf) was 69.4±8.2 and 74.5±8.2 years, respectively. The mean age of women with dynapenia (handgrip strength <16kgf) was 75.0±10.1 years and non-dynapenic women, 71.1±8.2 years. It was found that dynapenic women, with handgrip strength <20 and <16kgf, had an average of 2.38 and 2.47kg less muscle mass respectively, when compared to non-dynapenic women (p<0.05). However, there was no difference in muscle mass between the different dynapenic groups. Non-dynapenic women (handgrip strength ≥20kgf) had more total (3.55kg) and central fat (1.47kg) (p<0.05). Conclusion Dynapenic women, diagnosed considering both cutoff points, had less total and segmental muscle mass compared to non-dynapenic women. In addition, dynapenic women with handgrip strength <20kgf had lower total and trunk adiposity.

RESUMO Objetivo Comparar a composição corporal de mulheres na pós-menopausa com e sem dinapenia a partir de diferentes pontos de corte. Métodos A composição corporal foi avaliada por bioimpedância elétrica e o estado nutricional pelo índice de massa corporal. A dinapenia foi diagnosticada por meio da força de preensão manual, utilizando-se os seguintes pontos de corte: força de preensão manual <16kgf e <20kgf. Resultados Participaram da pesquisa 171 mulheres (50 a 92 anos). A média de idade das não dinapênicas e das dinapênicas (força de preensão manual <20 kgf) foi 69,4±8,2 e 74,5±8,2 anos, respectivamente. As mulheres com dinapenia pela força de preensão manual <16kgf apresentaram média de idade de 75,0±10,1 anos e as não dinapênicas tinham, em média, 71,1±8,2 anos. Verificou-se que as mulheres dinapênicas, com força de preensão manual <20 e <16kgf, tinham em média 2,38 e 2,47kg a menos de massa muscular quando comparadas às não dinapênicas (p<0,05). Contudo, não foi observada diferença na massa muscular entre os diferentes grupos dinapênicos. As mulheres não dinapênicas (força de preensão manual ≥20kgf) apresentaram maior gordura total (3,55kg) e central (1,47kg) (p<0,05). Conclusão As mulheres dinapênicas, diagnosticadas por ambos os pontos de corte, apresentaram menor massa muscular total e por segmento em relação às não dinapênicas. Ademais, as dinapênicas com força de preensão manual <20kgf possuíam menor adiposidade total e no tronco.

Electroacupuncture promotes recovery from disuse muscular atrophy through the miR-133a/SIRT1 pathway / 中华物理医学与康复杂志

Objective:To explore the role of microRNA-133a (miR-133a) and silent mating information regulation 2 homolog 1 (SIRT1) in the effects of electroacupuncture on persons with disuse muscular atrophy.Methods:Thirty C57BL/6 mice were randomly divided into a control group, an experimental control group and an experimental group, each of 10. Disuse muscular atrophy was induced in the mice of the experimental and experimental control groups using tail suspension. The mice in the electroacupuncture group were given 15 minutes of electroacupuncture over the Yanglingquan and Zusanli points every day for 14 days. Wet weight ratio and the cross-sectional area of the gastrocnemius and soleus were tracked, and the structure of the mitochondria in the skeletal muscles was observed using a transmission electron microscope. The protein expressions of SIRT1, peroxisome proliferator-activated receptor γ coactivator-1a (PGC-1a), nicotinamide phosphoribosyl transferase (NAMPT), adenosine 5-monophosphate-activated protein kinase-a (AMPK-a) and phospho-AMPK-a (P-AMPK-a) were detected using western blotting. The expressions of the muscle atrophy F-box (Atrogin-1), muscle ring finger1 (MuRF1), miR-133a, SIRT1, paired box gene 7 (Pax7), myogenic determination (MyoD) and myogenin (MyoG) genes were detected through polymerase chain reactions. The concentration of Niacylamide adenine dinucleotide (NAD+ ) and the ratio of NAD+ to reduced nicotinamide adenine dinucleotide were also measured.Results:Compared with the experimental control group, the average wet weight increased by 21% and the cross-sectional area of the soleus increased by 30% in the experimental group. The average wet weight of the gastrocnemius increased by 5% and the area by 17%. The average expressions of Atrogin-1, MuRF1, SIRT1, PGC-1a and NAMPT, the concentration of NAD+ , as well as the average value of P-AMPK-a/AMPK-a and NAD+ /NADH were significantly lower in the experimental group than in the experimental control group, while the average expression of miR-133a in the experimental group was significantly (163%) higher. The average expressions of Pax7 and MyoD were significantly up-regulated in the experimental control group compared with the other two groups, while MyoG was highly expressed in the experimental group compared with the other 2 groups.Conclusions:The SIRT1 pathway is one of the reflexive protective mechanisms that mediate in the natural recovery of skeletal muscles. Electroacupuncture enhances myoblast differentiation, improves energy metabolism in the mitochondria, and thus promotes recovery from disuse muscular atrophy.

Relationship between breath isoprene excretion and oxidative stress responses to submaximal exercise / 体力科学

The physiological functions of expiratory isoprene, which is abundantly contained in human breath, are not well known. Recently, breath isoprene has been proposed to be related to oxidative stress, although no direct evidence has been reported. Therefore, the purpose of this study was to investigate the relationship between breath isoprene and oxidative stress status. Ten healthy male subjects performed a 20-min submaximal step-load cycling exercise, the intensity of which corresponded to a 60% peak oxygen uptake after a 10-min rest. Breath isoprene excretion during the exercise was calculated from the product of minute ventilation and isoprene expiratory concentration. To evaluate the oxidative stress, we collected blood samples from the subject’s fingertips before and immediately after the end of the exercise, and then diacron reactive oxygen metabolites (d-ROMs), which is an index of oxidative stress level, and biological antioxidant potential (BAP), which is an index of antioxidant potential, were measured. The breath isoprene concentration at the rest was significantly positively correlated with the ratio from BAP to d-ROMs (BAP/d-ROMs), which is an index of latent antioxidant potential (r = 0.63, P < 0.05). Furthermore, the change in breath isoprene excretion from before to after the exercise was significantly negatively correlated with the change in d-ROMs (r = -0.73, P < 0.05) and positively correlated with the change in BAP/d-ROMs (r = 0.88, P < 0.01). These results suggest that isoprene might play a role in the control of oxidative stress.

Molecular cloning of troponin i from the two-spotted cricket, Gryllus bimaculatus, and its expression pattern during starvation / Clonagem molecular da Troponina I do grilo africano, Gryllus bimaculatus, e seu padrão de expressão durante a inanição

There is few information about troponin gene expression by starvation in insect skeletal muscle and digestive tracts. The objective of this study was to perform molecular cloning of troponin I from the two-spotted cricket, Gryllus bimaculatus (GrybiTnI) and determine its expression patterns in three different skeletal muscles and digestive tracts during starvation. GrybiTnI was translated into a protein encoding 198 amino acids with a theoretical isoelectric point of 9.78 and a molecular weight of 23671.46 Da. The GrybiTnI has both the TnC-binding site and actin/TnC-binding site shown in the typical TnI amino acid sequences. Homology analysis revealed that GrybiTnI exhibited high similarity at the amino acid level to those of other insects already reported; 89~77% identity with those of other insects. Expression of GrybiTnI by starvation did not change in dorsal wing flight muscle and dorsal ventral flight muscle, but showed up-expression in dorsal longitudinal flight muscle. In the digestive tracts, the up-expression of GrybiTnI by starvation was observed only in the hindgut but not in the rest parts including Malpighian tubules. Re-feeding following starvation restored those expressions about the level before starvation in the dorsal longitudinal flight muscle and hindgut. In conclusion, troponin modulates gene expression not only to muscle elements but also to physiological changes such as strains.

Existe pouca informação sobre a expressão gênica da troponina por inanição no músculo esquelético de insetos e no trato digestório. O objetivo deste estudo foi realizar clonagem molecular da troponina I do grilo africano, Gryllus bimaculatus (GrybiTnI) e determinar seus padrões de expressão em três diferentes músculos esqueléticos e tratos digestivos durante a inanição. GrybiTnI foi traduzido em uma proteína codificando 198 aminoácidos com um ponto isoelétrico teórico de 9,78 e um peso molecular de 23671,46 Da. O GrybiTnI tem o local de ligação a TnC e o local de ligação a actina/TnC mostrado nas sequências de aminoácidos TnI típicas. A análise de homologia revelou que GrybiTnI exibiu alta similaridade no nível de aminoácidos em relação àqueles de outros insetos já relatados; 89~77% de identidade com os de outros insetos. A expressão de GrybiTnI pela inanição não se alterou no músculo de vôo da asa dorsal e no músculo de vôo ventral dorsal, mas mostrou expressão positiva no músculo de vôo longitudinal dorsal. Nos tratos digestivos, a expressão positiva de GrybiTnI por inanição foi observada apenas no intestino grosso, mas não nas partes de repouso, incluindo os túbulos de Malpighi. A realimentação após a inanição restaurou as expressões aproximadamente ao nível antes da inanição no músculo de vôo longitudinal dorsal e no intestino grosso. Em conclusão, a troponina modula a expressão gênica não apenas em elementos musculares, mas também em alterações fisiológicas, como as cepas.

Massage relieves inflammation and oxidative stress and promotes autophagy after contusion of skeletal muscles / 中华物理医学与康复杂志

Objective To observe the effects of massage on inflammation,oxidative stress and autophagy during the repair of acute contusion of skeletal muscles so as to explore its biological mechanisms.Methods Forty-two adult Sprague-Dawley rats were randomly divided into a control group (n =6),a model group (n =18),and a treatment group (n =18).Acute contusion of the gastrocnemius muscles of the rats in the model and treatment groups was inflicted using a home-made impactor.Beginning forty-eight hours later,15 minutes of massage was administered daily for two weeks.After one,7 and 14 days of the massage treatment,the injured gastrocnemius was resected from 6 rats of both the model and treatment groups.Morphological changes were observed using haematoxylin and eosin (HE) staining.The serum content of tumor necrosis factor alpha (TNF-α),interleukin1β (IL-1 β),C reactive protein (CRP) and prostaglandin E2 (PGE2) were detected using enzyme-linked immunosorbent assay (ELISA).The serum content of superoxide (SOD) and malondialdehyde (MDA) were detected using spectrophotometry.The expression of microtubule-associated protein 1 light chain 3 (LC3),Bcl-2 homeodomain protein Beclin1 and ubiquitin binding protein P62 were detected using Western blotting.Results The HE staining showed more significant collapse and swelling of cells in the model group than in the control group at each time point.New muscle cells were observed at days 7 and 14 in the model group.At each time point,significantly better recovery was observed in the treatment group compared to the model group,with more new muscle cells and better cell morphology.According to the ELISA results,a significant increase in serum pro-inflammatory factors occurred in the model group compared to the control group and compared to the treatment group after one day and 7 days of treatment.The average serum content of SOD and MDA in the model group was significantly higher than in the control group,while the average serum content of SOD in the treatment group was significantly higher than in the model group and that of MDA was significantly lower.Western blotting showed a significant decrease in LC3 (Ⅱ/Ⅰ) and Beclin1,as well as a significant increase in P62 in the model group at each time point compared with the treatment group and the controls.Conclusion Inflammation and oxidative stress increase significantly in a skeletal muscle after injury,but autophagy decreases significantly.Massage can effectively reduce the inflammatory response and oxidative stress and promote autophagy,which leads to quicker repair of skeletal muscles.

Application progresses of real-time shear wave elastography in skeletal muscles / 中国医学影像技术

The central nervous system disease and musculoskeletal diseases often involve skeletal muscles.Quantitative evaluation of strength and hardness of a single muscle accurately and rapidly are basis for causation analysis of movement dysfunction.Real-time shear wave elastography (SWE) is a new ultrasonic imaging technique developed in recent years,and still has a preliminary application in the skeletal muscle system.The application and research progresses of SWE in auxiliary diagnosis of disease in skeletal muscles were reviewed in this article.

Application progresses of real-time shear wave elastography in skeletal muscles / 中国医学影像技术

The central nervous system disease and musculoskeletal diseases often involve skeletal muscles.Quantitative evaluation of strength and hardness of a single muscle accurately and rapidly are basis for causation analysis of movement dysfunction.Real-time shear wave elastography (SWE) is a new ultrasonic imaging technique developed in recent years,and still has a preliminary application in the skeletal muscle system.The application and research progresses of SWE in auxiliary diagnosis of disease in skeletal muscles were reviewed in this article.

Effects of mesenchymal stem cells on the expression of Bcl-2 and Bax in atrophied muscle / 中华物理医学与康复杂志

Objective To observe the effects of mesenchymal stem cells (BMSCs) on the expression of Bcl2 and Bax in atrophied muscles.Methods Immature rats (80～ 100 g) were anesthetized to collect marrow from their femurs and tibias.BMSCs were isolated from the marrow,cultured and purified using the whole bone marrow adherence method.Their right hindlimbs were immobilized fiom the thigh to the paw with the knee in extension and the ankle in plantar flexion.After the modeling,24 of the male rats were divided into a sham-operation group,a BMSC group and a phosphate buffer solution (PBS) group,each of 8.The BMSC and PBS groups were injected with either approximately 106 BMSCs or an equal volume of PBS into the belly of the soleus muscle after they had been immobilized for 48 hours,while the control group did not undergo any treatment except for the injection of PBS.All of the rats were sacrificed for analysis after 14 days.Results The BMSCs were mainly spindle cells,showing radial colony arrangement.They grew vigorously and could passage in a continuous and stable manner over 10 passages.At the 4th passage the BMSCs were positive for CD44 (95.84％) and CD90 (96.00％),but negative for CD34 and CD45.Western blotting assay demonstrated that the expression of Bax protein as measured in grey-scale value (0.41±0.08)in the BMSC group was significantly lower than in the PBS group (0.63±0.10),but significantly higher than in the control group (0.14±0.11) on average.The expression of Bcl-2 (0.47±0.14) was also significantly higher in the BMSC group than in the PBS group (0.22-± 0.13),but significantly lower than in the control group (0.81 ± 0.06).Conclusion Bone marrow mesenchymal stem cells can upregulate the expression of anti-apoptotic Bcl-2 protein and downregulate that of the apoptotic Bax protein when injected early into the belly of a muscle in an immobilized limb.

Insuficiencia renal aguda inducida por rabdomiolisis / Insuficiência renal aguda induzida por rabdomiólise / Acute renal failure due to rhabdomyolyisis

La insuficiencia renal aguda (IRA) es una causa frecuente de morbilidad y mortalidad en los servicios de urgencias, hospitalización y cuidado crítico, siendo la rabdomiolisis responsable del 15 % de los casos en los centros hospitalarios de alta complejidad. La rabdomiolisis consiste en daño muscular con necrosis y liberación a la circulación de componentes intracelulares, y puede tener múltiples causas. El daño renal por rabdomiolisis es multifactorial e incluye obstrucción tubular, vasoconstricción y daño oxidativo. El tratamiento principal de la IRA por rabdomiolisis es la hidratación, forzar la diuresis y evitar los fármacos nefrotóxicos. Cuando el daño es lo suficientemente grave para causar uremia, acidosis metabólica, hiperpotasemia y sobrecarga de volumen se debe recurrir a la terapia de reemplazo renal. Aunque la regla es que se recupere la función renal, estos pacientes tienen mayor riesgo futuro de desarrollar enfermedad renal crónica...

Acute renal failure is a frequent cause of morbidity and mortality in emergency, hospitalization and critical care services. In 15 % of cases it is due to rhabdomyolysis, in which there is breakdown of skeletal muscle with massive necrosis and leakage of muscle cell contents into the circulation. It has many different etiologies. The rhabdomyolysis-induced acute kidney injury results from the combination of several mechanisms, including tubular obstruction, vasoconstriction and oxidative stress. The most important therapeutic measures are: Aggressive repletion of fluids, forced diuresis and avoidance of exposure to nephrotoxic substances. In cases of severe uremia, metabolic acidosis, hiperkalemia or fluid overload it is necessary to start renal replacement therapy. As a rule, kidney function is completely recovered, but these patients have higher risk of future chronic kidney disease...

A insuficiência renal aguda (IRA) é uma causa frequente de morbidade e mortalidade entre os serviços de emergência, internação e cuidados críticos. A rabdomiólise é responsável por 15% dos casos. Consiste de dano muscular com necrose e liberação à circulação de componentes intercelulares, e pode ter varias causas. O dano renal por rabdomiólise é multifatorial e inclui obstrução tubular, vasoconstrição e dano oxidativo. O principal tratamento da IRA por rabdomiólise é a hidratação, forçar a diurese e evitar fármacos nefrotóxicos. Quando o dano é suficientemente grave para causar uremia, acidose metabólica, hiperpotassemia e sobrecarga de volume se deve recorrer à terapia de substituição renal. Embora a regra é que se recupera a função renal, esses pacientes têm um maior risco futuro de desenvolver doença renal crônica...

Effects of electroacupuncture on the expression of cyclin-dependent kinase 5 after skeletal muscle contusion / 中华物理医学与康复杂志

Objective To observe the effect of the electroacupuncture ( EA) on the expression of cyclin-de-pendent kinase 5 ( Cdk5 ) in rats with muscle contusion and to explore its mechanism. Methods Thirty-two Sprague-Dawley rats were randomly divided into a normal group of 4, a model group of 4, a natural recovery group ( NR) of 12 and an EA group of 12. All except those in the normal group had acute skeletal muscle contusion induced through a heavy blow. The EA group was treated with 15 minutes of EA daily beginning 48 h after the injury while the other rats received no EA. The model group was sacrificed 24 h after modeling, and rats from the NR and EA groups were sacrificed on the 7th, 14th and 21st day after the modeling to collect tissues. Hematoxylin eosin ( HE) staining, Western blotting and quantitative real-time fluorescence PCR were used to observe any histological changes, as well as Cdk5 protein and mRNA expression. Results The HE staining showed that the other 3 groups displayed larger a-mounts of muscle fiber fracture, dissolution and inflammatory cell invasion than was observed in the normal group. Compared with the NR group, quicker recovery was seen in the EA group as evidenced by faster muscle satellite cell proliferation and more new muscle fiber generation. The average Cdk5 protein expression in both the NR and EA groups was higher than in the normal group, and that of the EA group was significantly lower than that of the NR group. Conclusions Muscle contusion can increase Cdk5 expression in skeletal muscles, at least in rats. EA can promote the restoration of skeletal muscle function, probably by inhibiting CDK5 protein and mRNA expression.

High-intensity Interval Training for Aerobic Capacity and Physical Health (review) / 中国康复理论与实践

The high-intensity interval training often consisted of groups of interval high-intensity exercise of exhaustion or above 90%maximal oxygen consumption, which can be applied to improve aerobic capacity. Adaption of skeletal muscles might be resulted from high-intensity interval training, including recruitment, glucose metabolism and activity of mitochondrial oxidase, etc., and improve maxi-mum oxygen uptake. It has been used for physical fitness, such as weight reduction, rehabilitation of heart diseases and diabetes mellitus, etc.

The inhibitory effect of pulsed ultrasound on skeletal muscle fibrosis after injury in elderly rats / 中华物理医学与康复杂志

Objective To explore the inhibitory effect of pulsed ultrasound on skeletal muscle fibrosis after injury.Methods Thirty elderly male rats with gastrocnemius muscle injury were divided into an ultrasound group (UG) and a control group (CG) using a random number table.The injured muscles in the UG were treated using pulsed ultrasound (frequency 1 MHz,average strength 40 mW/cm2,duty cycle 20％) for 10 min daily from day 3 after the injury.The CG was given no treatment.On days 3,7,14,21 and 28 after the injury,histological and immunohistochemical analyses of the gastrocnemius muscles of both groups were performed.Results The collagen fiber mean optical density of the muscles increased gradually after the injury and reached its peak on day 21.It was significantly lower in the UG than in the CG on each test day.The expression of α-SMA increased gradually after the injury,but it too remained significantly lower in UG than that in CG.Conclusion Pulsed ultrasound may reduce collagen formation and α-SMA expression in injured skeletal muscle,and then inhibit muscle fibrosis.

Effect of muscle relaxation on the oxygenation of human skeletal muscle: a prospective in-vivo experiment using an isolated forearm technique / 대한마취과학회지

BACKGROUND: Total oxygen consumption has been found to be reduced under deep neuromuscular blockade due to a lower rate of metabolism of skeletal muscles. However, the magnitude of this effect in individual muscles has not been investigated. Thus the aim of this study was to compare the oxygenation of paralyzed versus non-paralyzed forearm muscle under tourniquet-provoked ischemia. METHODS: After ethics approval and written informed consent, 30 patients scheduled for elective hand and wrist surgery were included. Ischemia was provoked by inflation of bilateral upper arm tourniquets and muscle relaxation was achieved via intravenous administration of rocuronium 0.9 mg/kg. Bilateral tourniquets were applied to both upper arms before induction of anesthesia and near infrared spectrometry (NIRS) electrodes applied on both forearms. Muscular ischemia in an isolated (= non-paralyzed, NP) as well as a paralyzed forearm (P) was created by sequential inflation of both tourniquets before and after intravenous administration of rocuronium. Muscle oxygen saturations (SmO2) of NIRS in both forearms and their changes were determined and compared. RESULTS: Data of 30 patients (15 male, 15 female; 41.8 +/- 14.7 years) were analyzed. The speed of SmO2 decrease (50% decrease of SmO2 from baseline (median [percentiles]: NP 210 s [180/480s] vs. P 180 [180/300]) as well as the maximum decrease in SmO2 (minimum SmO2 in % (median [percentiles]: NP 20 [19/24] vs. P 21 [19/28]) were not significantly affected by neuromuscular paralysis. CONCLUSIONS: No significant effect of muscle relaxation on NIRS-assessed muscle oxygenation under tourniquet-induced ischemia was found in human forearm muscles.

Change of motor neurons and skeletal muscles distal to the lesion after spinal cord injury in rats / 中国组织工程研究

BACKGROUND:The majority of studies focus on the lesions of spinal cord injury, while little evidence is available on the change of morphology and structure of distal nerve, muscle and motor endplates fol owing spinal cord injury. OBJECTIVE:To investigate the time window change of the morphology of motor neurons and skeletal muscles caudal to the lesion after spinal cord injury in rats. METHODS:Fifty healthy adult Sprague-Dawley rats were randomly divided into three groups:control group (n=5;without treatment), sham operation group (n=10), and spinal cord injury group (n=35). The sham operated rats only received laminectomy. In the spinal cord injury group, rats were subject to complete T 10 spinal cord injury by total laminectomy and cord transverse resection. Then the morphological change including sciatic nerve, motor endplate and median gastrocnemius was observed for each group at 1, 2, 4, 12, 24 weeks after injury. RESULTS AND CONCLUSION:(1) The myelin sheath layers of sciatic nerve were separated partial y at 4 weeks in rats with spinal cord injury, the myelin sheaths were fragmented with the regeneration of thin-myelinated and unmyelinated axons at 12 weeks. There was a decrease in myelinated axons and an increase in thin-myelinated and unmyelinated axons at 24 weeks. (2) The synaptic gutters of motor endplate, the presynaptic and postsynaptic membrane and synaptic space were distinct at 4 weeks in rats with spinal cord injury, the degenerated motor endplates coexsisted with the intact ones at 12 weeks. The motor endplate disappeared at 24 weeks. (3) There was a slight decrease in muscle cross-sectional area at 2 weeks in rats with spinal cord injury, but no structural change was found, the membrane of myocytes was partial y weakened at 4 weeks, the border of myocytes was obscure with hyperplasia of connective tissue at 12 weeks, and myocytes gathered and in fusion at 24 weeks. As natural history of completely transected spinal cord injury in rats, there were significant changes in morphology of peripheral nerve, motor endplate and skeletal muscles caudal to the lesion at 12 weeks, and the changes were destructive at 24 weeks.

The mechanism of improving insulin resistance of skeletal muscles by ghrelin / 中华内分泌外科杂志

Objective To investigate the effects of acyl and deacyl ghrelin on the expressions of PI3Kp85α,Akt/PKB and GLUT4,the key factors in insulin receptor signaling pathway of insulin resistance in skeletal muscle cells.Methods Insulin resistance models were made by palmitic acid induced rat L6 myoblasts.Successful models were divided into acyl ghrelin group,deacyl ghrelin group,PI3K inhibitor(LY) + acyl ghrelin group,LY + deacyl ghrelin group and control group with corresponding interventions for 24h.The glucose uptake of all group was measured through laser confocal microscopy and flow cytometry.Expressions of phosphorated/total PI3Kp85α,phosphorated/total Akt and cell membrane/total GLUT4 of skeletal muscle cells were measured by Western blot,and PI3Kp85α,Akt,GLUT4 mRNA expression were detected by real-time PCR.Results Induced L6 myoblasts differentiation and insulin resistance model were successfully established.Acyl and deacyl ghrelin could increase glucose uptake for 1.25 and 1.28 folds compared to control group,and the phosphorated and total PI3Kp85α expressions were 1.78 and 1.89 folds to control group,and phosphorylated/total Akt and cell membrane/total GLUT4 were 1.84 and 1.80 folds to control group.The PI3Kp85α,Akt/PKB and GLUT4 mRNA expression were also upregulated compared to control group.The above indexes of LY + acyl or deacyl ghrelin group decreased significantly compared to acyl and deacyl ghrelin group without LY.Conclusions Acyl and deacyl ghrelin can both improve insulin resistance in skeletal muscle cells,increasing the glucose uptake under insulin-stimulation,and up-regulated the phosphorated PI3Kp85α,phosphorated Akt/PKB,and cell membrane GLUT4 relative protein expressions and mRNA expressions.PI3K inhibitor,LY294002,can inhibit the above improvement effect of acyl and decyl ghrelin.

Effects of nandrolone decanoate and resistance exercise on skeletal muscle in adult male rats / Efectos del decanoato de nandrolona y el ejercicio de resistencia en el músculo esquelético de ratas machos adultos

The aim of this study was to compare the effects of resistance exercise associated or not with nandrolone decanoate (ND) on skeletal muscles and body mass of adult male rats. Training protocol consisted of 15 jump sessions, for 6 weeks. ND (5mg/kg) was administered twice a week. The exercise was effective in inducing respective enlargements in fiber areas of extensor digitorum longus and soleus muscles. ND associate with exercise was also able to induce increases in fiber areas these muscles. In untrained group that received nandrolone decanoate an improved in muscular parameters could be observed. In conclusion, the resistance exercise was able to promote an enlargement in fiber areas of both muscles studied without ND treatment, indicating that after a period of time of adaptation to exercise, the muscular effects caused by ND could be achieved in the same way by exercise, without ND and without risks for health.

El objetivo de este estudio fue comparar los efectos del ejercicio de resistencia con o sin decanoato de nandrolona (DN) en el músculo esquelético y la masa corporal de ratas macho adultas. El protocolo de entrenamiento consistió en 15 sesiones durante 6 semanas de saltos. DN 5mg/kg se administró dos veces durante la semana. El ejercicio fue efectivo para inducir un aumento en el área de las fibras de los músculos extensor largo de los dedos y sóleo. El DN asociado con el ejercicio fue capaz de inducir un aumento en el área de las fibras de los músculos. En el grupo de DN sin entrenamiento, se observó un aumento en los parámetros musculares evaluados. El ejercicio de resistencia sin DN fue capaz de promover un aumento en el área de las fibras de los músculos, lo que indica que después de un período de adaptación al ejercicio, el efecto en los músculos causada por la DN se logró por el ejercicio, sin una gestión DN y los consiguientes peligros para la salud.

Changes of Apoptosis Related Factors in Atrophic Rat Skeletal Muscles after Denervation and Disuse

OBJECTIVE: To investigate the changes of apoptosis related factors after denervation and disuse in skeletal muscles and to find out the role of apoptosis in atrophic process. METHOD: 30 male Sprague-Dawley rats, 8 weeks of age were treated with three different atrophy models (10 rats in each group); hind-limbs suspension (HS) as a disuse model, complete denervation by sciatic nerve transsection (CD) and partial denervation by sciatic nerve crushing (PD). At 2 weeks and 4 weeks after each experiment, both gastrocnemius were dissected and their weights were measured. Western blotting for BAX and Bcl-2 and TUNEL assay were used to assess the changes of apoptosis related factors in muscle cell. RESULTS: The muscle weight of PD and CD group decreased 38.6%, 65.6%, respectively, of intact side at 4 weeks after injuries. The loss of muscle weight in HS group was smaller than that of denervated muscles. CD group showed high expression of BAX (3.45+/-0.32-->2.87+/-0.48) and Bcl-2 (3.63+/-0.40-->3.33+/-0.50) at 2 and 4 weeks after denervation, but in PD group, BAX at 2 weeks significantly decreased at 4 weeks (3.40+/-0.55-->2.13+/-0.25). In HS group, their expressions were slightly increased only immediate after 14 days suspension (BAX: 1.30+/-0.38 and Bcl-2: 1.29+/-0.28). CD group showed higher number of positive nuclei (27.6+/-8.8%) than PD group (10.4+/-5.3%) and HS group (4.4+/-1.6%) in TUNEL assay. CONCLUSION: Unlike temporary increase of apoptosis related factors in disuse, increase of these factors are remarkable and persisted after denervation. Muscle apoptosis may be the major cause of muscle atrophy during degeneration process.

Histomorphometric analysis of the response of rat skeletal muscle to swimming, immobilization and rehabilitation

The objective of the present study was to determine to what extent, if any, swimming training applied before immobilization in a cast interferes with the rehabilitation process in rat muscles. Female Wistar rats, mean weight 260.52 ± 16.26 g, were divided into 4 groups of 6 rats each: control, 6 weeks under baseline conditions; trained, swimming training for 6 weeks; trained-immobilized, swimming training for 6 weeks and then immobilized for 1 week; trained-immobilized-rehabilitated, swimming training for 6 weeks, immobilized for 1 week and then remobilized with swimming for 2 weeks. The animals were then sacrificed and the soleus and tibialis anterior muscles were dissected, frozen in liquid nitrogen and processed histochemically (H&E and mATPase). Data were analyzed statistically by the mixed effects linear model (P < 0.05). Cytoarchitectural changes such as degenerative characteristics in the immobilized group and regenerative characteristics such as centralized nucleus, fiber size variation and cell fragmentation in the groups submitted to swimming were more significant in the soleus muscle. The diameters of the lesser soleus type 1 and type 2A fibers were significantly reduced in the trained-immobilized group compared to the trained group (P < 0.001). In the tibialis anterior, there was an increase in the number of type 2B fibers and a reduction in type 2A fibers when trained-immobilized rats were compared to trained rats (P < 0.001). In trained-immobilized-rehabilitated rats, there was a reduction in type 2B fibers and an increase in type 2A fibers compared to trained-immobilized rats (P < 0.009). We concluded that swimming training did not minimize the deleterious effects of immobilization on the muscles studied and that remobilization did not favor tissue re-adaptation.