An evaluation of an animal model of cerebral palsy: the effects on the morphology of the extensor digitorum longus muscle / Evaluación de un modelo animal de parálisis cerebral: los efectos sobre la morfología del músculo extensor largo de los dedos

Cerebral Palsy (CP) refers to chronic childhood encephalopathy. The objective of this study was to verify effects of CP model that combines prenatal exposure to LPS, perinatal anoxia and sensorimotor restriction on EDL muscle. Male Wistar rat pups were separated: a) Control - pups of mothers injected with saline during pregnancy and b) Cerebral Palsy - pups of mothers injected with LPS during pregnancy, and submitted to perinatal anoxia and sensorimotor restriction. The CP group presented hypertrophy in the type IIB fibers and increase of nuclei/fiber and capillary/fiber ratios. The intrafusal fibers of CP group presented 26 % atrophy in the crosssectional area and intramuscular collagen volume increase 34 %. CP group showed myofibrillar disruption and Z-line disorganization and the NMJs presented increases of 22 % in area.This animal model of CP produces motor deficits and macro and microscopic alterations and in the ultrastructure of the EDL muscle.

La parálisis cerebral (PC) se refiere a la encefalopatía crónica infantil. El objetivo de este estudio fue verificar los efectos del modelo PC que combina la exposición prenatal a LPS, la anoxia perinatal y la restricción sensitivo-motora en el músculo extensor largo de los dedos (MELD). Se separaron las crías de ratas Wistar machos: a) Control: crías de madres inyectadas con solución salina durante la preñez y b) Parálisis cerebral: crías de madres inyectadas con LPS durante la preñez y sometidas a anoxia perinatal y restricción sensitivo-motora. El grupo PC presentó hipertrofia en las fibras tipo IIB y aumento de la relación núcleo / fibra y capilar / fibra. Las fibras intrafusales del grupo PC presentaron un 26 % de atrofia en el área de la sección transversal y el volumen de colágeno intramuscular aumentó un 34 %. El grupo PC mostró disrupción miofibrilar y desorganización de la línea Z y los NMJ presentaron aumentos de 22 % en el área. Este modelo animal de PC produce déficit motores y alteraciones macro y microscópicas y cambios en la ultraestructura del MELD.

Morphological and morphometric study of the muscle fibers and neuromuscular junctions of the extensor digitorum longus in aged rats submitted to maternal protein restriction / Estudio morfológico y morfométrico de las fibras musculares y de las intersecciones neuromusculares del músculo extensor largo de los dedos de ratas de edad avanzada sometidas a la restricción proteica materna

Protein restriction implies the functional involvement of several systems and organs, including the skeletal muscle, because it is a protein reservoir in the body. This study sought to analyze the morphological and morphometric features of the muscle fibers and neuromuscular junctions (NMJs) of the extensor digitorum longus (EDL) muscle in rats at 365 days of age, submitted to maternal protein restriction during the gestation and lactation periods. Wistar rats were divided into two groups: a Control Group - mothers fed a normal-protein diet (17 % protein) during pregnancy and lactation; and a Restricted Group - mothers fed a low-protein diet (6 % protein) during pregnancy and lactation. The pups were kept with the mother throughout the lactation period (21 days), after which the offspring received a normal protein diet until 365 days of age. Histological (HE) and histoenzymological (NADH-TR) studies were conducted on the muscle fibers. The muscle was subjected to Nonspecific Esterase reaction to stain the Neuromuscular Junctions. Regarding the animals from the restricted group: the histologic analysis of the muscle fibers showed the presence of centralized nuclei and a diminished area; the histoenzymological study showed the different types of muscle fibers were randomly distributed in the EDL muscle and the area of the Type IIa muscle fiber was smaller; the ultrastructural study revealed disorganization of the Z line, and the presence of lipid droplets and vacuoles containing myelin figures in subsarcolemmal and intramiofibrilar regions; while the analysis of the NMJs exhibited no significant differences between the groups. Protein restriction in the pregnancy and lactation period may have affected the development of skeletal muscle, producing a permanent muscle-fiber deficit in the EDL muscle of the offspring.

La restricción proteica implica compromiso funcional de diversos sistemas y órganos, entre ellos, el músculo estriado esquelético, por ser una reserva de proteína del organismo. De esa forma, el presente trabajo procuró analizar las características morfológicas y morfométricas de las fibras musculares y de las intersecciones neuromusculares (JNMs) del músculo extensor largo de los dedos (EDL) en ratas de 365 días de edad, sometidas a restricción proteica materna durante los periodos de gestación y lactancia. Las ratas Wistar fueron separadas en dos grupos: El grupo Control - madres alimentadas durante la gestación y lactancia con ración normoproteica (17 % de proteína) y Grupo con restricción ­ madres alimentadas durante la gestación y lactancia con ración hipoproteica (6 % de proteína). Las crías permanecieron con la madre durante todo el periodo de lactancia (21 días) y después de este periodo la prole recibió ración normoproteica hasta los 365 días de edad. Se realizó un estudio histológico (HE) e histoenzimológico (NADH-TR) de las fibras musculares. Para la marcación de las JNMs, el músculo fue sometido a la reacción de Esterasa Inespecífica. El análisis histológico de las fibras musculares de los animales del Grupo con restricción mostró la presencia de núcleos centralizados y una disminución del área en el grupo con restricción. En el estudio histoenzimológico, el músculo EDL presentó una distribución aleatoria de los diferentes tipos de fibras musculares y el área de las fibras musculares del tipo IIa fue menor en el grupo con restricción. En relación al estudio ultraestructural, en los animales del grupo con restricción se observó desorganización de la línea Z, presencia de pequeñas gotas de lípidos y vacuolas que abrigaban figuras de mielina en las regiones subsarcolemal e intramiofibrilar. En el análisis de las JNMs no hubo diferencias significativas. La restricción proteica impuesta en el periodo de gestación y lactancia puede haber afectado el desarrollo del músculo esquelético, produciendo un déficit permanente en las fibras musculares del músculo EDL de la prole.

Effects of calorie restriction for 8 weeks on contractile function and mito-chondrial biosynthesis in different types of rat skeletal muscles / 中国病理生理杂志

AIM:To investigate the influence of calorie restriction ( CR) on contractility and mitochondrial bi-osynthesis in different types of rat skeletal muscles .METHODS:CR rat model was set up by feeding 60%normal food in-take of control rat every day for 8 weeks.Soleus (SOL) and extensor digitorum longus (EDL) were isolated under anesthe-sia.The twitch tension, titanic tension and fatigue resistance of SOL and EDL in response to electrical stimulation were measured to reflect the contractile function of the muscles .The copy number ratio of mitochondrial gene cytochrome C oxi-dase subunit I ( COX I) to nuclear gene β-actin was determined to evaluate the mitochondrial biosynthesis .ATP content was measured to mirror mitochondrial function .RESULTS:Compared with control group , CR for 8 weeks significantly in-creased twitch tension and titanic tension of both SOL and EDL , but only improved fatigue resistance in SOL .Markedly in-crease in ATP content in both skeletal muscles by CR intervention was observed , especially in SOL .Although CR activated AMP-activated protein kinase (AMPK) in both 2 muscles, up-regulation of mitochondrial biosynthesis and transcription of mitochondrial regulatory genes peroxisome proliferator-activated receptor γcoactivator 1α( PGC-1α) and nuclear respirato-ry factor ( NRF) was only observed in SOL .CONCLUSION:CR for 8 weeks enhanced the contractility of both rat SOL and EDL in response to electrical stimulation , especially in SOL composed of slow-twitch fibers.The mechanisms may be related to the activation of AMPK and the promotion of mitochondrial biosynthesis in SOL .

Streptozotocin Diabetes Attenuates the Effects of Nondepolarizing Neuromuscular Relaxants on Rat Muscles

The hypothesis of this study was that diabetes-induced desensitization of rat soleus (SOL) and extensor digitorum longus (EDL) to non-depolarizing muscle relaxants (NDMRs) depends on the stage of diabetes and on the kind of NDMRs. We tested the different magnitude of resistance to vecuronium, cisatracurium, and rocuronium at different stages of streptozotocin (STZ)-induced diabetes by the EDL sciatic nerve-muscle preparations, and the SOL sciatic nerve-muscle preparations from rats after 4 and 16 weeks of STZ treatment. The concentration-twitch tension curves were significantly shifted from those of the control group to the right in the diabetic groups. Concentration giving 50% of maximal inhibition (IC50) was larger in the diabetic groups for all the NDMRs. For rocuronium and cisatracurium in both SOL and EDL, IC50 was significantly larger in diabetic 16 weeks group than those in the diabetic 4 weeks group. For SOL/EDL, the IC50 ratios were significantly largest in the diabetic 16 weeks group, second largest in the diabetic 4 weeks group, and smallest for the control group. Diabetes-induced desensitization to NDMRs depended on the stage of diabetes and on the different kind of muscles observed while was independent on different kind of NDMRs. The resistance to NDMRs was stronger in the later stage of diabetes (16 versus 4 weeks after STZ treatment). Additionally, when monitoring in SOL, diabetes attenuated the actions of neuromuscular blockade more intensely than that in EDL. Nonetheless, the hyposensitivity to NDMRs in diabetes was not relevant for the kind of NDMRs.

BILATERAL VARIATIONS IN TENDONS OF DORSUM OF FOOT.

Anterior or extensor muscles of foot comprises Peroneus tertius (PT), Extensor digitorum longus (EDL), Extensor hallucis longus (EHL) and Tibialis anterior (TA). Presence of PT in many of the primates and humans suggests terrestrial bipedalism. PT is a dorsi-flexor of ankle joint and a weak evertor of foot. TA is the most medial and superficial dorsiflexor. Standard text-books describe the course of tendon of TA as passing deep to inferior extensor retinaculum (IER). In the present study, absence of PT with a course of TA superficial to IER on one side with variant origin of PT from Extensor digitorum longus on the other side were observed in an adult female cadaver. Knowledge on variations in PT and TA are of clinical significance and academic importance to orthopedic surgeons, radiologists and anatomists.

Efeito da corrente alternada simétrica sinusoidal na musculatura estriada esquelética desnervada experimentalmente / Effect of sinusoidal alternated current in experimentally denerved skeletal striated muscle

Introdução: A utilização da estimulação elétrica (EE) no tratamento de músculos desnervados tem sido muito estudada, pois auxilia na reinervação tardia e minimiza a atrofia muscular. Objetivo: Neste estudo, avaliamos a EE através da corrente alternada simétrica sinusoidal na manutenção dos aspectos morfológicos dos músculos Extensor longo dos dedos (EDL) e Sóleo desnervados experimentalmente. Método: Quarenta ratos da linhagem wistar foram divididos em quatro grupos experimentais (n=10): Em grupo controle inicial (GCI), controle Final (GCF), desnervado (GD), e em desnervado e estimulado (GDE). A aplicação EE no músculo EDL e sóleo teve início 48 horas após a lesão nervosa, sendo aplicada três vezes por semana durante quarenta e cinco dias. Cortes transversais foram corados com HE para a mensuração da morfometria das fibras musculares. Para a análise estatística foi utilizado a análise de variância (one-way - ANOVA) seguido pelo teste de tukey (p < 0,05). Resultados: Os animais do grupo D e DE apresentaram uma diminuição da área de secção transversal (AST) quando comparadas ao CF. Porém o grupo DE minimizou a atrofia muscular, pois houve diferença estatisticamente significativa quando comparado ao D, tanto no músculo EDL quanto no sóleo. Conclusão: A EE foi eficiente na manutenção dos aspectos morfológicos dos músculos EDL e sóleo, minimizando a atrofia muscular. Podendo ser um tratamento útil para as lesões nervosas periféricas.

Introduction: the use of electrical stimulation (ES) in the treatment of denervated muscles has been studied as it assists in the late reinnervation and minimizes muscle atrophy. Purpose: this study assessed the ES through the symmetric sinusoidal alternating current in the maintenance of the morphological aspects of the experimentally denervated Extensor digitorum longus (EDL) and Soleus muscles. Method: Forty Wister rats were divided into four experimental groups (n = 10): initial control group ( ICG), final control group (FCG), denervated group (DG) and denervated and stimulated group (DSG). ES was first applied in the soleus and EDL muscle 48 hours after nerve injury, the applications took place three times per week for forty-five days. Cross-sections were stained with HE to perform the morphometric analysis of the muscle fibers. We used the analysis of variance (one-way - ANOVA) followed by the Tukey test (p < 0.05) for statistical analysis. Results: the animals belonging to group D and DE showed a decrease in the crosssectional area (CSA) when compared to FCG. However, the group DE had muscular atrophy minimized, as there was a statistically significant difference when compared to D, both for EDL and soleus muscles. Conclusion: the ES was effective in maintaining the morphological aspects of the EDL and soleus muscles, minimizing muscle atrophy. This may be a useful treatment for the peripheral nerve injuries.

Effects of Creatine Supplements on Contractile Properties of Skeletal Muscle in Elder Rats / 中国康复理论与实践

Objective To investigate the effects of creatine supplement on contractile properties of soleus (SOL) and extensor digitorum longus (EDL) in elder rat. Methods 20 male Sprague-Dawley rats were randomly divided into control group and creatine supplement group with 10 rats in each group. After 6 weeks, the content of creatine and phosphocreatine were detected by high performance liquid chromatog-raphy, and contractile properties were examined in SOL and EDL in vitro at 30℃. Results The content of creatine and phosphocreatine both in SOL and EDL were higher in the creatine supplement group than in the control group (P0.05). Creatine supple-ments significantly increased the fatigue resistance of the SOL and there was no significant effect on EDL. The force potentiation which oc-curred in EDL during the initial 20~30 s of the fatigue test significantly increased (P<0.05). Conclusion Creatine supplement is effective on the contractile properties of SOL and EDL in elder rats, but the effect is dependent on the fiber types.

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.

Response of masticatory muscles to passive stretch stimulus - from perspectives of functional appliances / 대한치과교정학회지

OBJECTIVE: The aims of this study were to examine whether a passive stretch stimulus by means of a functional appliance induces changes in the fiber composition of masticatory muscles and whether these changes are similar to the changes in stretched limb muscle fibers by using RT-PCR, western blot, and immunohistochemical assays. METHODS: Five male New Zealand White rabbits were fitted with a prefabricated inclined plane on the maxillary central incisors to force the mandible forward (- 2 mm) and downward (- 4 mm). Further, 1 hind limb was extended and constrained with a cast so that the extensor digitorum longus (EDL) was stretched when the animal used the limb. The animals were sacrificed after 1 week and the masseter, lateral pterygoid, and EDL were processed and compared with those from control animals (n = 3). RESULTS: The stretched EDL had a significantly higher percentage of slow fibers, whereas the stretched masticatory muscles did not show changes in the composition of the major contractile proteins after 7 days. CONCLUSIONS: The transition of fiber phenotypes in response to a stretch stimulus may take longer in the masticatory muscles than in the limb muscles.

Ultrastructural study of the neuromuscular junctions of extensor digitorum longus muscle (M. extensor digitorum longus) of the mice / Estudio ultraestructural de las uniones neuromusculares del músculo extensor largo de los dedos (M. extensor digitorum longus) del ratón

The neuromuscular junction of the extensor digitorum longus muscle of fingers was analyzed in 21 young (three months) and old (from six to 25 months) mice, from both genders. Morphologic changes were found throughout the mouse life, being more frequent and visible with aging. According with the data described in the literature consulted and the observations taken in this research, it becomes clear that a continuous process of morphological remodeling occurs in all neuromuscular ultrastructural junctions of the extensor digitorum longus muscle of fingers, during the life of the animal. Theses changes are characterized by figures of myelin in the cytoplasm of Schwann cells, pleomorphic and multivesiclar bodies, mitochondrias with morphologically altered crests in the axon terminal and degenerated junction folders. Coated vesicles are common in older animals and rare in young animals.

La ultraestructura de las uniones mioneurales del músculo extensor largo de los dedos fue analizada en 21 ratones, jóvenes (tres meses) y viejos (de seis a 25 meses), de ambos sexos. Los cambios morfológicos fueron encontrados en toda la vida del ratón, siendo más frecuentes y visibles en el envejecimiento. Según los datos descritos en la literatura comsultada y las observaciones tomadas en esta investigación, se concluye que un proceso continuo de remodelación morfológica ocurre en todas las uniones mioneurales del músculo extensor largo de los dedos, durante la vida del animal. Tales cambios son caracterizados por figuras de mielina en el citoplasma de las células del neurilema, cuerpos pleomórficos y multivesiculares, mitocondrias con crestas morfologicamente cambiadas y pliegues de unión degeneradas. Las vesículas son comunes en animales más viejos y raras en animales jóvenes.

Traumatic Dynamic Hallux Varus: A Case Report / 대한족부족관절학회지

The first metatarsophalangeal joint injury is common in professional soldiers and athletes. But this was rarely reported. A professional soldier has varus instability in the first metatarsophalangeal joint due to hyperextension. In the MR Imaging, weavy appearance in lateral collateral ligament and high signal change in plantar plate was shown. So he has surgical treatment using reconstructive procedure. At first, 4th extensor digitorum longus tendon was splitted longitudinally and harvested, second triangular shape reconstruction on lateral joint line was done using harvested tendon. One year later, fifteen degrees was limited compared with intact side. Reconstruction using 4th extensor digitorum longus tendon in traumatic dynamic hallux varus was good method.

Cross-Leg Achilles Tendon Reconstruction Using a Composite Flap of Dorsalis Pedis and Tendon Strips of the Extensor Digitorum Longus in a Vascular Compromised Wound

Reconstructions of soft tissue defect of the posterior ankle including Achilles the tendon should take into account not only coverage but functional outcome. Various methods of tendon transfer and tendon graft have been reported as a single-stage procedure. With advances and refinements in microsurgical techniques, several free composite flaps including tendon, fascia, or nerve have been used in single-stage reconstructions of large defects in this area minimizing further damage to the traumatized leg. However, when free flap is not feasible for some reasons, this cannot be accomplished successfully. Here we present a patient with Achilles tendon and circumferential large soft tissue defect. Because of circulatory compromise of the lower extremity, free flap reconstruction could not be applied. Instead, cross-leg composite flap of the dorsalis pedis flap including the extensor hallucis brevis musle and tendon, and tendon strips of the Second, third and fourth extensor digitorum logus were employed, Functional reconstruction of the tendon and resurfacing were obtained at the same time. The flap was detached 3 weeks postoperatively, and the transplanted flap has survived without any complications. By 3 months after surgery, full weight bearing, tip-toe standing and even walking without crutch assistance was possible. When functional reconstruction with the free flap is unattainable in the large defect of the posterior ankle including the Achilles tendon, cross-leg composite island flap of dorsalis pedis flap and tendon strips of the extensor digitorum longus tendon is a viable alternative.