Histochemistry profile of the biceps brachii muscle fibres of capuchin monkeys (Cebus apella, Linnaeus, 1758) / Perfil histoquímico das fibras do músculo bíceps braquial do macaco-prego (Cebus apella, Linnaeus, 1758)

A general analysis of the behaviour of “Cebus” shows that when this primate moves position to feed or perform another activity, it presents different ways of locomotion. This information shows that the brachial biceps muscle of this animal is frequently used in their locomotion activities, but it should also be remembered that this muscle is also used for other development activities like hiding, searching for objects, searching out in the woods, and digging in the soil. Considering the above, it was decided to research the histoenzimologic characteristics of the brachial biceps muscle to observe whether it is better adpted to postural or phasic function. To that end, samples were taken from the superficial and deep regions, the inserts proximal (medial and lateral) and distal brachial biceps six capuchin monkeys male and adult, which were subjected to the reactions of m-ATPase, NADH-Tr. Based on the results of these reactions fibres were classified as in Fast Twitch Glycolitic (FG), Fast Twitch Oxidative Glycolitic (FOG) and Slow Twitc (SO). In general, the results, considering the muscle as a whole, show a trend of frequency FOG> FG> SO. The data on the frequency were studied on three superficial regions FOG=FG>SO; the deep regions of the inserts proximal FOG=FG=SO and inserting the distal FOG>FG=SO. In conclusion, the biceps brachii of the capuchin monkey is well adapted for both postural and phasic activities.(AU)

Uma análise geral do comportamento do “Cebus apella” mostra que este primata quando desloca para se alimentar ou realizar outra atividade apresenta diferentes maneiras de locomoção. Estas informações mostram que o músculo bíceps braquial deste animal é usado freqüentemente nas suas atividades de locomoção, mas deve ser lembrado ainda que este músculo é usado também para desenvolvimento de outras atividades como esconder-se, procurar objetos, vasculhar arboredos, além de cavar o chão. Considerando-se o exposto acima decidiu-se pesquisar as características histoenzimológicas do músculo bíceps braquial do macaco-prego com o objetivo de comparar se este músculo esta melhor adaptado para funções posturais ou fásicas. As amostras foram retiradas das regiões superficiais e profundas; inserções proximais (medial e lateral) e distal de seis macacos-prego machos e adultos, os quais foram submetidos às reações de m-ATPase, NADH-Tr. Baseado nos resultados das reações, as fibras foram classificadas em Fast Twitch Glycolitic (FG), Fast Twitch Oxidative Glycolitic (FOG) e Slow Twitch (SO). Quanto à área dos diferentes tipos de fibras, os resultados encontrados foram semelhantes em todas as amostras estudadas, e as fibras de contração rápida foram sempre maiores do que as de contração lenta (FG=FOG>SO). Os dados obtidos sobre a frequência foram: nas três regiões superficiais estudadas FOG=FG>SO; nas regiões profundas das inserções proximais FOG=FG=SO e na inserção distal FOG>FG=SO. Baseado nestes dados pode-se concluir que o músculo bíceps braquial do macaco-prego está bem adaptado tanto para atividades posturais como fásicas.(AU)

Histochemistry profile of the biceps brachii muscle fibres of capuchin monkeys (Cebus apella, Linnaeus, 1758) / Perfil histoquímico das fibras do músculo bíceps braquial do macaco-prego (Cebus apella, Linnaeus, 1758)

A general analysis of the behaviour of “Cebus” shows that when this primate moves position to feed or perform another activity, it presents different ways of locomotion. This information shows that the brachial biceps muscle of this animal is frequently used in their locomotion activities, but it should also be remembered that this muscle is also used for other development activities like hiding, searching for objects, searching out in the woods, and digging in the soil. Considering the above, it was decided to research the histoenzimologic characteristics of the brachial biceps muscle to observe whether it is better adpted to postural or phasic function. To that end, samples were taken from the superficial and deep regions, the inserts proximal (medial and lateral) and distal brachial biceps six capuchin monkeys male and adult, which were subjected to the reactions of m-ATPase, NADH-Tr. Based on the results of these reactions fibres were classified as in Fast Twitch Glycolitic (FG), Fast Twitch Oxidative Glycolitic (FOG) and Slow Twitc (SO). In general, the results, considering the muscle as a whole, show a trend of frequency FOG> FG> SO. The data on the frequency were studied on three superficial regions FOG=FG>SO; the deep regions of the inserts proximal FOG=FG=SO and inserting the distal FOG>FG=SO. In conclusion, the biceps brachii of the capuchin monkey is well adapted for both postural and phasic activities.

Uma análise geral do comportamento do “Cebus apella” mostra que este primata quando desloca para se alimentar ou realizar outra atividade apresenta diferentes maneiras de locomoção. Estas informações mostram que o músculo bíceps braquial deste animal é usado freqüentemente nas suas atividades de locomoção, mas deve ser lembrado ainda que este músculo é usado também para desenvolvimento de outras atividades como esconder-se, procurar objetos, vasculhar arboredos, além de cavar o chão. Considerando-se o exposto acima decidiu-se pesquisar as características histoenzimológicas do músculo bíceps braquial do macaco-prego com o objetivo de comparar se este músculo esta melhor adaptado para funções posturais ou fásicas. As amostras foram retiradas das regiões superficiais e profundas; inserções proximais (medial e lateral) e distal de seis macacos-prego machos e adultos, os quais foram submetidos às reações de m-ATPase, NADH-Tr. Baseado nos resultados das reações, as fibras foram classificadas em Fast Twitch Glycolitic (FG), Fast Twitch Oxidative Glycolitic (FOG) e Slow Twitch (SO). Quanto à área dos diferentes tipos de fibras, os resultados encontrados foram semelhantes em todas as amostras estudadas, e as fibras de contração rápida foram sempre maiores do que as de contração lenta (FG=FOG>SO). Os dados obtidos sobre a frequência foram: nas três regiões superficiais estudadas FOG=FG>SO; nas regiões profundas das inserções proximais FOG=FG=SO e na inserção distal FOG>FG=SO. Baseado nestes dados pode-se concluir que o músculo bíceps braquial do macaco-prego está bem adaptado tanto para atividades posturais como fásicas.

Histochemistry profile of the biceps brachii muscle fibres of capuchin monkeys (Cebus apella, Linnaeus, 1758).

A general analysis of the behaviour of "Cebus" shows that when this primate moves position to feed or perform another activity, it presents different ways of locomotion. This information shows that the brachial biceps muscle of this animal is frequently used in their locomotion activities, but it should also be remembered that this muscle is also used for other development activities like hiding, searching for objects, searching out in the woods, and digging in the soil. Considering the above, it was decided to research the histoenzimologic characteristics of the brachial biceps muscle to observe whether it is better adpted to postural or phasic function. To that end, samples were taken from the superficial and deep regions, the inserts proximal (medial and lateral) and distal brachial biceps six capuchin monkeys male and adult, which were subjected to the reactions of m-ATPase, NADH-Tr. Based on the results of these reactions fibres were classified as in Fast Twitch Glycolitic (FG), Fast Twitch Oxidative Glycolitic (FOG) and Slow Twitc (SO). In general, the results, considering the muscle as a whole, show a trend of frequency FOG> FG> SO. The data on the frequency were studied on three superficial regions FOG=FG>SO; the deep regions of the inserts proximal FOG=FG=SO and inserting the distal FOG>FG=SO. In conclusion, the biceps brachii of the capuchin monkey is well adapted for both postural and phasic activities.

Differential developmental programming by early protein restriction of rat skeletal muscle according to its fibre-type composition.

AIMS: Differences in fibre-type composition of skeletal muscle have been associated with obesity and insulin resistance. As a poor nutrient environment early in life is a predisposing factor for the development of obesity and related metabolic diseases at adulthood, this study aimed at determining the long-term consequences of maternal undernutrition on the structural and metabolic properties of two skeletal muscles characterized by their different fibre-type composition and metabolic properties. METHODS: The fibre-type composition and enzymatic activities of hexokinase (HK), beta-hydroxyacyl-CoA dehydrogenase (ß-HAD) and citrate synthase (CS) were measured in soleus and extensor digitorum longus (EDL) muscles from adult rats born to dams fed a control (17% protein) or a low-protein [8% protein (PR)] diet throughout pregnancy and lactation. In addition, the expression levels of several genes regulating glycolysis, fatty acid oxidation and mitochondrial biogenesis were determined by real-time PCR. RESULTS: Protein rats exhibited enhanced density of type II fibres along with decreased rate of fatty acid oxidation and glycolysis in soleus but not EDL. Malnourished rats exhibited also a different gene expression profile in soleus and EDL. Altogether, these alterations correspond to a state of energy deficiency and are present in animals which do not show yet any sign of obesity or glucose intolerance. CONCLUSION: We conclude that maternal protein restriction alters in the long term the structural and enzymatic properties of offspring skeletal muscle in a fibre-type-dependent manner. These alterations might have a causative role in the development of obesity and related metabolic disorders later in life.

Expression of sarcoplasmic-endoplasmic reticulum Ca-ATPase isoforms in masticatory muscles.

The aim of this study was to characterize the sarcoplasmic-endoplasmic reticulum Ca-ATPase (SERCA) isoforms in rabbit masticatory muscles compared with those in fast-twitch muscle. It was hypothesized that combined expression of the SERCA isoforms in fast- and slow-twitch muscles accounts for lower Ca-ATPase activity. SERCA was isolated by differential centrifugation, the isoforms were determined by ELISA, and the activity of each isoform was measured using a colorimetric method. Activity was tested for significance by anova, and the distribution of isoforms was assessed using the chi-square test (P < 0.05) and correlated to SERCA activity using Spearman's rank correlation. SERCA1 was predominant (90.5%) in fast-twitch muscle, whereas a mixture of SERCA isoforms was found in masticatory muscles: 62-78% was SERCA2, 20-37% was SERCA1, and the SERCA3 content was negligible. Depressor muscles showed a significantly higher content (77.8%) of SERCA2, and elevator muscles showed a higher content (35.4%) of SERCA1. Elevator muscles showed higher expression of SERCA2a (58%), and depressor muscles showed higher expression of SERCA2b (20%). The SERCA1 content was mainly SERCA1a and significantly higher for elevator muscles (33%), whereas depressor muscles showed a higher content of SERCA1b (4%). The SERCA1 content of fast-twitch muscle was mainly SERCA1a (88.5%). It is concluded that the mixture of different SERCA isoforms, along with a substantial content of SERCA2b, in masticatory muscles would support lower Ca-ATPase activity and calcium transport.

Fiber type composition of the sternomastoid and diaphragm muscles of dystrophin-deficient mdx mice.

The muscle fiber phenotype is mainly determined by motoneuron innervation and changes in neuromuscular interaction alter the muscle fiber type. In dystrophin-deficient mdx mice, changes in the molecular assembly of the neuromuscular junction and in nerve terminal sprouting occur in the sternomastoid (STN) muscle during early stages of the disease. In this study, we were interested to see whether early changes in neuromuscular assembly are correlated with alterations in fiber type in dystrophic STN at 2 months of age. A predominance of hybrid fast myofibers (about 52% type IIDB) was observed in control (C57Bl/10) STN. In mdx muscle, the lack of dystrophin did not change this profile (about 54% hybrid type IIDB). Pure fast type IID fibers predominated in normal and dystrophic diaphragm (DIA; about 39% in control and 30% in mdx muscle) and a population of slow Type I fibers was also present (about 10% in control and 13% in mdx muscle). In conclusion, early changes in neuromuscular assembly do not affect the fiber type composition of dystrophic STN. In contrast to the pure fast fibers of the more affected DIA, the hybrid phenotype of the STN may permit dynamic adaptations during progression of the disease.

Cyclosporin A preferentially attenuates skeletal slow-twitch muscle regeneration.

Calcineurin, a Ca2+/calmodulin-dependent phosphatase, is associated with muscle regeneration via NFATc1/GATA2-dependent pathways. However, it is not clear whether calcineurin preferentially affects the regeneration of slow- or fast-twitch muscles. We investigated the effect of a calcineurin inhibitor, cyclosporin A (CsA), on the morphology and fiber diameter of regenerating slow- and fast-twitch muscles. Adult Wistar rats (259.5 +/- 9 g) maintained under standard conditions were treated with CsA (20 mg/kg body weight, ip) for 5 days, submitted to cryolesion of soleus and tibialis anterior (TA) muscles on the 6th day, and then treated with CsA for an additional 21 days. The muscles were removed, weighed, frozen, and stored in liquid nitrogen. Cryolesion did not alter the body weight gain of the animals after 21 days of regeneration (P = 0.001) and CsA significantly reduced the body weight gain (15.5%; P = 0.01) during the same period. All treated TA and soleus muscles showed decreased weights (17 and 29%, respectively, P < 0.05). CsA treatment decreased the cross-sectional area of both soleus and TA muscles of cryoinjured animals (TA: 2108 +/- 930 vs 792 +/- 640 microm(2); soleus: 2209 +/- 322 vs 764 +/- 439 m(2); P < 0.001). Histological sections of both muscles stained with Toluidine blue revealed similar regenerative responses after cryolesion. In addition, CsA was able to minimize these responses, i.e., centralized nuclei and split fibers, more efficiently so in TA muscle. These results indicate that calcineurin preferentially plays a role in regeneration of slow-twitch muscle.

Cyclosporin A preferentially attenuates skeletal slow-twitch muscle regeneration

Calcineurin, a Ca2+/calmodulin-dependent phosphatase, is associated with muscle regeneration via NFATc1/GATA2-dependent pathways. However, it is not clear whether calcineurin preferentially affects the regeneration of slow- or fast-twitch muscles. We investigated the effect of a calcineurin inhibitor, cyclosporin A (CsA), on the morphology and fiber diameter of regenerating slow- and fast-twitch muscles. Adult Wistar rats (259.5 ± 9 g) maintained under standard conditions were treated with CsA (20 mg/kg body weight, ip) for 5 days, submitted to cryolesion of soleus and tibialis anterior (TA) muscles on the 6th day, and then treated with CsA for an additional 21 days. The muscles were removed, weighed, frozen, and stored in liquid nitrogen. Cryolesion did not alter the body weight gain of the animals after 21 days of regeneration (P = 0.001) and CsA significantly reduced the body weight gain (15.5 percent; P = 0.01) during the same period. All treated TA and soleus muscles showed decreased weights (17 and 29 percent, respectively, P < 0.05). CsA treatment decreased the cross-sectional area of both soleus and TA muscles of cryoinjured animals (TA: 2108 ± 930 vs 792 ± 640 µm²; soleus: 2209 ± 322 vs 764 ± 439 m²; P < 0.001). Histological sections of both muscles stained with Toluidine blue revealed similar regenerative responses after cryolesion. In addition, CsA was able to minimize these responses, i.e., centralized nuclei and split fibers, more efficiently so in TA muscle. These results indicate that calcineurin preferentially plays a role in regeneration of slow-twitch muscle.

Histochemical differences in the responses of predominantly fast-twitch glycolytic muscle and slow-twitch oxidative muscle to veratrine.

The aim of this study was to investigate if the Na(+)-channel activating alkaloid veratrine is able to change the oxidative and m-ATPase activities of a fast-twitch glycolytic muscle (EDL, extensor digitorum longus) and slow-twitch oxidative muscle (SOL, soleus) in mice. Oxidative fibers and glycolytic fibers were more sensitive to veratrine than oxidative-glycolytic fibers 15, 30 and 60 min after the i.m. injection of veratrine (10 ng/kg) with both showing an increase in their metabolic activity in both muscles. In EDL, the m-ATPase reaction revealed a significant (p < 0.001) decrease (50%) in the number of type IIB fibers after 30 min while the number of type I fibers increased by 550%. Type I fibers decreased from 34% in control SOL to 17% (50% decrease) in veratrinized muscles, with a 10% decrease in type IIA fibers within 15 min. A third type of fiber appeared in SOL veratrinized muscle, which accounted for 28% of the fibers. Our work gives evidence that the changes in the percentage of the fiber types induced by veratrine may be the result, at least partially, from a direct effect of veratrine on muscle fibers and else from an interaction with the muscle type influencing distinctively the response of a same fiber type. Based on the results obtained in the present study the alterations in EDL may be related to the higher number of Na(+) channels present in this muscle whereas those in SOL may involve an action of veratrine on mitochondria. Although it is unlikely that the shift of enzymes activities induced by veratrine involves genotypic expression changes an alternative explanation for the findings cannot be substantiated by the present experimental approach.

Histoenzymology and morphometry of the masticatory muscles of tufted capuchin monkey (Cebus apella Linnaeus, 1758).

Samples of the anterior and posterior regions of the masseter and temporal muscles and of the anterior belly of the digastric muscle of 4 adult male tufted capuchin monkeys (Cebus apella) were removed and stained with HE and submitted to the m-ATPase reaction (with alkaline and acid preincubation) and to the NADH-TR and SDH reactions. The results of the histoenzymologic reactions were similar, except for acid reversal which did not occur in fibers of the fast glycolytic (FG) type in the mandibular locomotor muscles. FG fibers had a larger area and were more frequent in all regions studied. No significant differences in frequency or area of each fiber type were detected, considering the anterior and posterior regions of the masseter and temporal muscles. The frequency of fibers of the fast oxidative glycolytic (FOG) and slow oxidative (SO) types and of FOG area differed significantly between the anterior belly of the digastric muscle and the mandibular locomotor muscle. The predominance of fast twitch (FG and FOG) fibers and the multipenniform and bipenniform internal architecture of the masseter and temporal muscles, respectively, are characteristics that permit the powerful bite typical of tufted capuchin monkeys.

Morphometric evaluation of muscle fiber types in different skeletal muscles of rats.

The purpose of the present work was to study some morphological differences of similar muscle fiber types--classified by ATPase reactions in different muscles of rats. Morphological parameters were used as stereological techniques at light and electron microscopic level. There was a great variation in the diameter of each muscle fiber type of different muscles. The smallest diameter of type 1 myofibers of the soleus was greater than the diameter of type 1 myofibers of other muscles. The diameter of type 1 myofibers of the soleus and of the lateral part of the gastrocnemius was almost twice the diameter of type 1 myofibers of sternocleidomastoid. The lateral and medial parts of gastrocnemius had the largest 2A and 2B muscle fibers. As a whole, among the studied muscles, myofibers of postural muscles of the posterior parts of the posterior limbs had the greatest diameter. Stereological analysis at electron microscopic level revealed that there were differences in the volume density of mitochondria in the different muscles. The quantity of mitochondria was greater in the diaphragm than in the gastrocnemius, soleus and sternocleidomastoid muscles. Our results suggested that the diameter of muscle fibers is more related to the resistance the muscle is submitted than to the continuous necessity of contraction. However, the quantity of mitochondria of oxidative fibers of the diaphragm would be related to continuous necessity of contraction and high oxidative necessity of this muscle.

Muscle fiber composition and capillarization in relation to metabolic alterations in hypertensive men.

The aim of this study was to determine if there is a relationship among skeletal muscle fiber composition, capillarization, blood pressure (BP) and/or the components of the metabolic syndrome. Two groups were compared: 8 recently diagnosed, untreated, hypertensive men (BP > or = 140/90) and 7 normotensive men as controls. Muscle biopsies were taken from the vastus lateralis part of quadriceps femoris muscle in order to assess: fiber type proportion, capillarization, hexokinase, citrate synthase, beta-hydroxyacyl CoA dehydrogenase activities; lipoprotein lipase mass and activity, free fatty acids and triglycerides. Serum levels of insulin, glucose, cholesterol, uric acid and triglycerides were also assayed. Hypertensive patients had higher insulin levels and insulin resistance [homeostasis model assessment (HOMA)], a decreased hexokinase activity and an increase of muscle lipoprotein lipase mass as compared to controls. Interestingly, correlations among values differ in each group. The percentage of type IIB fibers was related to diastolic BP (blood pressure) in control and to mean BP in hypertensive subjects. Serum cholesterol and glucose were inversely related to the percentage of type I fibers in the control subjects. Negative correlations between capillarization and glucose, cholesterol and uric acid levels were found in control subjects. In all subjects, a strong correlation was found between SBP (systolic BP) and DBP (diastolic BP), and insulin resistance (IR) and uric acid levels. Muscle fiber type proportion and capillarization were related to blood pressure and components of the metabolic syndrome.

Histoenzymological and ultrastructural changes in lateral muscle fibers of Oreochromis niloticus (Teleostei: Cichlidae) after local injection of veratrine.

The effects of veratrine have been investigated in mammalian, amphibian, and crustacean muscle, but not in fish. In this work, the action of veratrine was studied in the lateral muscle of the freshwater teleost Oreochromis niloticus after intramuscular injection. Histoenzymological typing and electron microscopy of muscle fibers before and 15, 30, and 60 min after veratrine injection (10 ng/kg fish) were used to indirectly assess the morphological changes and the oxidative and m-ATPase activities. In some cases, muscles were pretreated with tetrodotoxin to determine whether the ultrastructural changes were the result of Na(+) channel activation by veratrine. Veratrine altered the metabolism of fibers mainly after 30 min. Oxidative fibers showed decreased NADH-TR activity, whereas that of glycolytic and oxidative-glycolytic type fibers increased. There was no change in the m-ATPase activity of the three fiber types, except at 60 min postveratrine, when a novel fiber type, which showed no reversal after acidic and alkaline preincubations, appeared. Ultrastructural damage involved sarcomeres, myofibrils, and mitochondria, but the T-tubules remained intact. Pretreatment with tetrodotoxin (1 ng/ml) prevented the ultrastructural changes caused by veratrine. These results show that in fish skeletal muscle veratrine produces some effects that are not seen in mammalian muscle.

Capillary changes in skeletal muscle of patients with essential hypertension.

Arterial hypertension produces changes along the vascular tree. However, there are few reports on its effect on human muscle capillaries. This study demonstrates the effects of essential hypertension on the capillaries of human quadriceps muscle. Muscle biopsy was taken from quadriceps femoris in eight men with recent diagnosis of essential hypertension, without treatment. Biopsies were also taken from eight normotensive men and were used as controls. Fiber types were classified by ATPase reaction, capillaries counted in alpha-amylase-PAS stained sections and ultrastructure studied by conventional methods of transmission electron microscopy. No changes were found in capillaries or muscle fiber types by histochemical methods. However, electron microscopy revealed abnormal capillaries with endothelial cells infoldings into the lumen, as well as occluded or degenerated capillaries. In some cases the endothelial cell area covered by pericytes was increased. Basement membrane of capillaries was frequently increased in width, sometimes irregularly, and in other instances it was reduplicated. In transversely sectioned capillaries lumen diameter was reduced and wall thickness was increased, although total diameter was unchanged. In hypertensive patients the finding of some degenerated capillaries adjacent to muscle fibers could be interpreted as the beginning of a process of rarefaction. Some capillaries showed morphological changes, and the ratio wall thickness/lumen was increased.

Inactivity changed fiber type proportion and capillary supply in cat muscle.

The effect of different levels of activity on fiber types, capillaries and enzymes of gastrocnemius and soleus muscles was studied in two groups of cats. The first group was successfully kept in a large room, exercised on a treadmill 15 min daily 5 days per week and kept in individual small cages. Each period lasted 6 weeks. A muscle biopsy was taken after each period. The second group was formed by cats that were caged for over 20 months. In the group caged for over 20 months, gastrocnemius muscle showed higher IIB and lower I fiber type proportion. Fiber cross-sectional area was not different in any condition. All capillary measurements were significantly lower in gastrocnemius muscle of long-term caged cats, and capillaries per mm2 were lower in soleus muscle of these cats. Exercise increased capillary/fiber in soleus muscle but subsequent caging did not reduced it. In soleus muscle, beta-hydroxy-acyl-CoA dehydrogenase levels decreased after the cage period and hexokinase levels increased after the exercise and decreased after the cage period. In conclusion, different levels of activity for short time produced enzyme changes in soleus muscle, whereas long-term inactivity changed fiber type proportion in gastrocnemius muscle and reduced capillary supply.