Clinical aspects, food management, and clinical evolution of a cat with hypertrophic muscular dystrophy / Aspectos clínicos, manejo alimentar e evolução clínica de um gato com distrofia muscular hipertrófica

Hypertrophic feline muscular dystrophy (HFMD), rarely reported in the literature, is a disease caused by a hereditary recessive dystrophin deficiency linked to the X chromosome, mainly affecting young male cats. Here, we presented the clinical aspects, food management, and clinical evolution of a seven-year-old mixed-breed cat diagnosed with HFMD, having a primary history of progressive tongue protrusion.

A distrofia muscular hipertrófica felina é uma doença causada por uma deficiência da distrofina com caráter hereditário recessivo ligado ao cromossomo X, com poucos registros de ocorrência na literatura, que acomete principalmente gatos machos jovens. Neste trabalho, são relatados os aspectos clínicos, manejo alimentar e evolução clínica de um gato, sem raça definida, de sete anos com histórico principal de protrusão progressiva da língua e diagnosticado com distrofia muscular hipertrófica felina.

Noninvasive evaluation of respiratory muscles in pre-clinical model of Duchenne Muscular Dystrophy / Avaliação não invasiva dos músculos respiratórios no modelo pré-clinico da Distrofia Muscular de Duchenne

Since respiratory insufficiency is the main cause of death in patients affected by Duchenne Muscular Dystrophy (DMD), the present study aims at establishing a new non-invasive method to evaluate the clinical parameters of respiratory conditions of experimental models affected by DMD. With this purpose in mind, we evaluated the cardiorespiratory clinical conditions, the changes in the intercostal muscles, the diaphragmatic mobility, and the respiratory cycles in Golden Retriever Muscular Dystrophy (GRMD) employing ultrasonography (US). A control group consisting of dogs of the same race, but not affected by muscular dystrophy, were used in this study. The results showed that inspiration, expiration and plateau movements (diaphragm mobility) were lower in the affected group. Plateau phase in the affected group was practically non-existent and showed that the diaphragm remained in constant motion. Respiratory rate reached 15.5 per minute for affected group and 26.93 per minute for the control group. Expiration and inspiration movements of intercostal muscles reached 8.99mm and 8.79mm, respectively, for control group and 7.42mm and 7.40mm, respectively, for affected group. Methodology used in the present analysis proved to be viable for the follow-up and evaluation of the respiratory model in GRMD and may be adapted to other muscular dystrophy experimental models.

Uma vez que, a insuficiência respiratória é a principal causa de morte em pacientes afetados pela Distrofia Muscular de Duchenne (DMD), o presente estudo avaliou as condições clínicas cardiorrespiratórias, o movimento dos músculos intercostais, a mobilidade diafragmática, os ciclos respiratórios e a expansão da cavidade torácica em cães Golden Retriever com Distrofia Muscular (GRMD) por ultrassonografia (US) a fim de estabelecer um novo método não invasivo para avaliar os parâmetros de avaliação clínica de doenças respiratórias de modelos experimentais afetados por DMD. Um grupo controle constituído por cães da mesma raça e espécie, mas não afetados pela distrofia muscular também foram utilizados neste estudo. Os resultados mostraram que os movimentos de inspiração, expiração e platô (mobilidade do diafragma) foram menores no grupo afetado. A fase de platô no grupo afetado foi praticamente inexistente e mostrou que o diafragma destes animais permaneceu em constante movimento. A frequência respiratória atingiu 15,5 por minuto para o grupo afetado e 26,93 para o controle. Movimento de expiração e inspiração dos músculos intercostais atingiu 8,99 milímetros e 8,79 milímetros, respectivamente para o grupo controle e 7,42 milímetros e 7,40 milímetros, respectivamente para o grupo afetado. A metodologia utilizada nesta análise foi viável para o acompanhamento e avaliação do modelo respiratória em modelo GRMD e pode ser adaptado para outros modelos experimentais de distrofia muscular.

Laparoscopic guided local injection in the X-linked muscular dystrophy mouse (mdx) diaphragm. An advance in experimental therapies for Duchenne Muscular Dystrophy

PURPOSE: To investigate the development of a laparoscopy technique for local injection into the X-linked muscular dystrophy (mdx) diaphragm. METHODS: It was used 10 mice Balb/C57 and 5 mdx mice and three differents decubitus type were tested: the right lateral, supine, and supine decubitus with 20 degrees elevation of the forelimb. Abdominal caudal face and the 10 intercostal space were tested as spot to introduce the needle into the diaphragm. RESULTS: Supine position with elevation of 20 degrees forelimb and the 10th intercostal space are the beneficial position to apply a local injection. CONCLUSION: It was proved to be possible to perform the laparoscopy technique in the X-linked muscular dystrophy diaphragm and this requires a specific position and technique during the surgery. .

Alterações morfofuncionais renais em cães Golden Retriever Distróficos (GRMD) / Kidneys morphological changes in Golden Retriever Muscular Dystrophy dogs (GRMD)

A Golden Retriever Muscular Dystrophy (GRMD) é geneticamente homóloga à distrofia muscular de Duchenne (DMD) que acomete seres humanos. É uma doença genética que gera degeneração progressiva da musculatura esquelética. Considerando-se as intensas alterações musculares, é natural pensar em uma possível lesão renal decorrente da intensa lesão muscular. Foram avaliados seis cães machos da raça Golden Retriever afetados pela distrofia muscular (GRMD) e três cães machos clinicamente sadios. A concentração de creatinina foi determinada e as proteínas urinárias foram avaliadas por eletroforese em gel de poliacrilamida. Os resultados mostraram que a proteinúria patológica não está diretamente associada à Distrofia Muscular de Duchenne, porém diversos parâmetros apresentaram concentrações aumentadas para animais afetados, como a razão proteína/albumina, que foi maior em cães distróficos, podendo ser indício de microalbuminúria e conseqüente lesão renal precoce. Estes resultados visam embasar avaliações clínicas e futuros estudos considerando-se as patologias decorrentes ou associadas a esta doença genética.

The Golden Retriever Muscular Dystrophy (GRMD) is genetically homologous to Duchenne muscular dystrophy (DMD) that affects humans. It is a genetic disease that causes progressive degeneration of skeletal muscle. Considering the intense muscle changes, it is natural to think in possible kidney damage caused by intense muscle injury. We evaluated six male Golden Retriever dogs affected by Duchenne muscular dystrophy (GRMD) and three clinically healthy male dogs. The urinary proteins and creatinine concentration were determined. The proteins were analyzed by polyacrylamide gel electrophoresis. The results showed that pathological proteinuria is not directly associated with Duchenne muscular dystrophy, but several parameters showed increased concentrations for affected animals, as the ratio protein/albumin, which was higher in dystrophic dogs, probably a consequence of microalbuminuria a sign of early kidney damage. These results aim to base future studies and clinical evaluations considering the pathologies arising from or associated with this genetic disease.

Estudo morfofuncional dos rins de cães da raça Golden Retriever afetados pela distrofia muscular (GRMD) / Morphofunctional study in kidneys of Golden Retriever dogs affected by muscular dystrophy (GRMD)

A Distrofia Muscular de Duchenne (DMD) é uma miopatia severa de caráter recessivo ligada ao cromossomo X e o modelo animal de estudo mais relevante é o Golden Retriever Muscular Dystrophy (GRMD). Além das severas alterações que ocorrem na musculatura estriada, muitos estudos mostram que outras estruturas, inclusive viscerais, podem se mostrar alteradas nesta patologia. Desta forma, este trabalho objetivou análisar e comparar possíveis alterações estruturais e funcionais do rim em cães GRMD. Neste modelo de estudo, foi possível observar a presença das faces convexa e côncava, do hilo renal e dos pólos craniais e caudais dos rins. O órgão mostrou-se envolto por uma cápsula fibrosa. Em um corte sagital do órgão, notou-se a presença das regiões cortical e medular e da pelve renal. Na análise microscópica foi possível identificar a zona medular e cortical com suas estruturas: os corpúsculos renais formados pelo glomérulo e pela cápsula de Bowman, os túbulos contorcidos proximais e distais, os ductos coletores, vasos sanguíneos e os segmentos das Alças de Henle. As dosagens séricas de creatinina e uréia encontram-se dentro dos limites de normalidade. Desta forma, de acordo com os nossos resultados, podemos concluir que os animais afetados estudados, não apresentaram alterações estruturais ou funcionais dos rins, o que nos permitir sugerir que apesar da ingestão hídrica comprometida, a estrutura renal, mantem- se preservada nos animais GRMD.

Duchenne muscular dystrophy (DMD) is a severe myopathy of recessive X-linked character and the most relevant animal study model is the Golden Retriever muscular dystrophy (GRMD). In addition to the severe changes occurring in the striated musculature, several studies show that other structures, including viscera, may prove to be altered in this pathology. Thus, this study aimed to analyze and compare possible structural and functional alterations of the kidney in GRMD dogs. In this study model, it was possible to observe the presence of convex and concave faces, the renal hilum, and the cranial and caudal poles of the kidneys. The organ was surrounded by a fibrous capsule. In a sagittal section of the organ, the presence of the cortical and medullary regions and the renal pelvis were noticed. On microscopic examination, it was possible to identify the medullary and cortical zones and their structures: the renal corpuscles formed by the glomerulus and Bowman's capsule, the proximal and distal convoluted tubules, the collecting ducts, the blood vessels, and the segments of the loops of Henle. The serum creatinine and urea were within normal limits. Thus, according to our results, we may conclude that the affected animals under study showed no structural or functional changes in the kidneys, something which allows us to suggest that, despite the impaired water intake, renal structure remains preserved in GRMD animals.

Imagem radiográfica da cavidade torácica de cães Golden Retriever acometidos pela distrofia muscular / Radiologic images of the thoracic cavity of Golden Retriever dogs affected by muscular dystrophy

A distrofia muscular de Duchenne (DMD) é uma doença de origem genética, cuja principal manifestação clínica é enfraquecimento e atrofia progressiva dos músculos. Os cães da raça Golden Retriever podem apresentar distrofia muscular, com características genotípicas e fenotípicas muito próximas à distrofia muscular humana, sendo considerado o modelo animal mais apropriado para o estudo da DMD. Foram realizadas radiografias torácicas látero-laterais e dorsoventrais de 10 cães Golden Retriever afetados pela distrofia muscular, com o objetivo de relatar as alterações radiográficas associadas a essa patologia. O exame radiográfico da cavidade torácica evidenciou: (a) padrão pulmonar intersticial e alveolar predominante, (b) um quadro de pneumonia e edema pulmonar em fase inicial, (c) a cardiomegalia como o principal achado de comprometimento circulatório na cavidade torácica, (d) O megaesôfago torácico foi observado deslocando a traquéia e silhueta cardíaca ventralmente e, (e) a cúpula diafragmática apresentou modificação morfológica, mostrando protrusão para o interior da cavidade torácica e hérnia hiatal, com deslocamento do estômago para o espaço mediastino caudal. Os achados de necropsia evidenciaram efusão pleural e enfisema pulmonar e lesões compatíveis com processos degenerativos e metaplásicos da musculatura diafragmática e intercostal. A avaliação radiográfica constituiu-se como um meio diagnóstico auxiliar essencial na identificação de doença cardíaca e respiratória em cães Golden Retriever acometidos pela Distrofia Muscular, capaz de identificar processos pneumônicos primários, permitindo o estabelecimento de terapêutica adequada de tratamento, com prognóstico reservado nos estágios mais avançados desta alteração.

Duchenne Muscular Dystrophy (DMD) is a genetic disorder with clinical signs of muscular weaknesses and progressive atrophy. Golden Retriever dogs show similar genotypic and phenotypic characteristics to Human Muscular Dystrophy and are considered a proper animal model for DMD studies. Latero-lateral and dorso-ventral thoracic radiographies were obtained from 10 Golden Retriever dogs affected by muscular dystrophy, to investigate possible radiographic alterations. Thorax radiographic examination revealed (a) interstitial and alveolar pattern, (b) initial phases of pneumonia and pulmonary edema, (c) cardiomegaly as a principal alteration in the thoracic cavity, (d) megaesophagus displacing the trachea and heart silhouette, and (e) cranial protrusion of the diaphragm lining into the thorax with development of a hiatus hernia displacing the stomach to the caudal mediastinum. Postmortem examination showed pleural effusion, pulmonary emphysema, degenerative and metaplasic processes in the diaphragm and intercostal muscles. Radiographic examination was considered essential for the diagnosis of cardiac and respiratory disease in Golden Retriever dogs affected by muscular dystrophy, and to identify the primary pulmonary process and to provide the establishment of suitable therapeutic treatment, with a reserved prognosis in advanced stage of the disease.

Estudo longitudinal da densidade mineral óssea de cães Golden Retriever hígidos, portadores e afetados pela distrofia muscular / Longitudinal study of bone mineral density in healthy, carrier, and affected dogs by Golden Retriever Muscular Dystrophy

A Distrofia Muscular do Golden Retriever (GRMD) é considerada o modelo mais apropriado da Distrofia Muscular de Duchenne (DMD)que acomete humanos. Diminuição na Densidade Mineral Óssea(DMO) já foi descrita em meninos com DMD, ambulantes e não ambulantes. A Densitometria Óptica Radiográfica (DOR) é um método de análise para quantificação da matéria mineral óssea. Este foi realizado por meio de radiografias simples da região proximal da tíbia direita ao lado de escala de alumínio. Quinze cães da raça Golden Retriever, sendo cinco normais, cinco portadores e cinco afetados pela distrofia, foram radiografados mensalmente, dos três aos nove meses de idade. Estas radiografias foram analisadas por meio do software deanálise de imagens (ImageLab, Softium®). O estudo revelou que a região epifisária possui maior densidade mineral óssea (DMO), seguida pela região metafisária e diafisária. Houve uma tendência de aumento da DMO nas três regiões avaliadas dos três grupos durante o experimento. A região metafisária proximal da tíbia demonstrou sero sitio de eleição para a leitura da DMO, por ser o local com menor correlação e influencia do peso corpóreo e por promover estimativas médias consideradas significativas entre grupos avaliados mais cedo que nas demais regiões. O potencial de diagnóstico deste exame densitométrico, em relação a GRMD, foi considerado baixo, porém, demonstrou ter grande potencial no acompanhamento do progresso desta doença por apresentar alta sensibilidade para detecção de variações na densidade mineral óssea.

The Golden Retriever Muscular Dystrophy (GRMD) is considered the most appropriate model of the Duchenne Muscular Dystrophy(DMD) in humans. Decrease in Bone Mineral Density (DMO) has been recognized in ambulatory and non-ambulatory boys with DMD.The Radiographic Optical Densitometry is a method to measure the bone mineral content. It was performed radiographing the proximal right tibia next to an aluminum stepwedge. Fifteen Golden Retriever dogs had been used, divided in three groups: Five healthy, five carriers and five affected by GRMD, monthly radiographed, from 3 to 9 months-old. These radiographies were analyzed by image processing software (ImageLab, Softium®). The proximal epiphysis had higher bone mineral density, followed for the metaphysic and diaphysis, respectively. All regions followed has influence the body weight. There was an increase of the bone mineral density in all regions of the three groups. The proximal metaphysis was thought to be the better region to evaluate the bone mineral density because had less correlation and influence of the body weight, and, also, had different significant values to differentiate the groups earlier than the other regions. The potential diagnostic of this densitometric method in GRMD was considered low, however it demonstrated to have great potential in the clinical recheck of this patients due to the high sensitivity for detection of changes in the bone mineral density

Mesenchymal stem cells transplanted in mdx mice differentiate into myocytes and express dystrophin/utrophin / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the differentiation of rat bone marrow mesenchymal stem cells (MSCs) into myocytes and their expression of dystrophin/utrophin after transplantation in mdx mice.</p><p><b>METHODS</b>BrdU-labeled fifth-passage rat MSCs were transplanted in mdx mice with previous total body gamma irradiation (7 Gy). At 4, 8, 12 and 16 weeks after the transplantation, the mice were sacrificed to detect dystrophin/BrdU and utrophin expressions in the gastrocnemius muscle using immunofluorescence assay, RT-PCR and Western blotting. Five normal C57 BL/6 mice and 5 mdx mice served as the positive and negative controls, respectively.</p><p><b>RESULTS</b>Four weeks after MSC transplantation, less than 1% of the muscle fibers of the mdx mice expressed dystrophin, which increased to 15% at 16 weeks. Donor-derived nuclei were detected in both single and clusters of dystrophin-positive fibers. Some BrdU-positive nuclei were centrally located, and some peripherally within myofibers. Utrophin expression decreased over time after transplantation.</p><p><b>CONCLUSION</b>The myofibers of mdx mice with MSC transplantation express dystrophin, which is derived partially from the transplanted MSCs. Dystrophin expression from the transplanted MSCs partially inhibits the upregulation of utrophin in mdx mouse muscle, showing a complementary relation between them.</p>

Análise das dosagens e concentrações séricas da ciclosporina A em cães da raça Golden Retriever normais ou afetados pela distrofia muscular / Analyses of dosages and blood concentration of cyclosporin A on norrmal Golden Retriever dogs or Golden Retriever with muscular dystrophy

A distrofia muscular dos cães Golden Retriever (GRMD), uma miopatia degenerativa causada pela ausência da distrofina é geneticamente homóloga à distrofia muscular de Duchenne que acomete humanos, portanto, estes cães são considerados modelos experimentais para estudos em terapia celular. Seu sucesso depende da imunossupressão adequada. A ciclosporina A (CsA) é indicada para tal e a monitorização de suas concentrações sangüíneas e efeitos adversos são essenciais para viabilizar a terapia. Foram estudados cães GRMD, e normais da mesma raça, submetidos a terapia com CsA, associada, nos GRMD, ao transplante de células tronco. Foram avaliados as concentrações sangüíneas do fármaco através de amostras coletadas a cada dois ou três dias e analisadas pelo método do imunoensaio por fluorescência (FPIA). Como resultado observamos que as concentrações de CsA oscilaram muito, em seis dos oito animais. Concluímos que as doses variam individualmente sendo de maior importância avaliar a concentração do fármaco no sangue e sua viabilização no uso da terapia celular

The muscular dystrophy of Golden Retriever (GRMD) is a degenerative miopaty caused by the absence of dystrophy and it is genetically homologue of the Duchenne muscular dystrophy in humans, so, these dogs are considerably experimental models for studies on cellular therapy. Their successful depends of the adequate immunosuppression. Cyclosporin A (CsA) is indicated for that and the monitoring of the blood concentration and adverse effects are essential to viabilise the therapy. It was studied GRMD dogs, and normal dogs from the same breed, submitted for therapy with CsA, associated, on GRMD, of cell transplantation. It was evaluated blood concentration of the drug, between two or tree days using the method of FPIA. In our results we found that the CsA blood concentrations oscillated too much on six than eight of our animals. We concluded that the doses varieties Braz. J. vet. Res. anim. Sci., São Paulo, v. 45, n. 2, p. 131-137, 2008 individually and the correct dosage as to important as the evaluation of the blood concentration of the drug and became viable for cell therapy

Efeitos da ciclosporina a sobre a função renal de cães da raça Golden Retriever normais ou afetados pela distrofia muscular / Effect of cyclosporin A on renal functions of normal Golden Retriever dogs or Golden Retriever with muscular dystrophy

A distrofia muscular dos cães Golden Retriever (GRMD), uma miopatia degenerativa causada pela ausência da distrofina, é geneticamente homóloga à distrofia muscular de Duchenne que acomete humanos, portanto, estes cães são considerados modelos experimentais para estudos em terapia celular. Seu sucesso depende da imunossupressão adequada. A ciclosporina A é indicada para tal e a monitorização de suas concentrações sangüíneas e efeitos adversos são essenciais para viabilizar a terapia. Foram estudados cães GRMD e normais da mesma raça, submetidos à terapia com CsA, associada, nos GRMD, ao transplante de células tronco. Foram avaliados os possíveis efeitos do fármaco sobre a função renal, sendo consideradas as manifestações clínicas, urinálise, testes de função glomerular, e concentrações séricas de uréia, creatinina, sódio e potássio. Como resultado houve aumento discreto na uréia sérica de ambos os grupos; cilindrúria e proteinúria e aumento da densidade urinária no grupo dos GRMD. Concluímos que a CsA pode causar lesão aguda de túbulos renais, principalmente em GRMDs; os mesmos também reagem de modo distinto com relação à homeostase de íons e função renal. Entretanto, diagnóstico precoce e tratamento podem prevenir o agravamento das lesões e desenvolvimento de insuficiência renal.

The muscular dystrophy of Golden Retriever is a degenerative miopaty caused by the absence of dystrophy and it is genetically homologue of the Duchenne muscular dystrophy in humans, so, these dogs are considerably experimental models for studies on cellular therapy. Their successful depends of the adequate immunosuppression. Cyclosporin A is indicated for that and the monitoring of blood concentration and adverse effects are essential to viabilise the therapy. It was studied GRMD dogs, and normal dogs from the same breed, submitted for therapy with CsA, associated, on GRMD, of cell transplantation. It was evaluated the possible effects of the drug on renal functions. It has been considerate the clinic manifestations, urinalisis, testis of glomerular function and blood concentrations of urea, cretinine, sodium and potassium. In our results we found a discrete increase of blood urea on booth groups; increased levels of urine's cylinders and protein and also increase of urinary density on GRMD group. CsA therapy could make acute lesions on renal tubules, especially on GRMD. These dogs also have different reactions than normal dogs on relation of ions homeostasis and renal function. However, earlier diagnosis and adequate treatment could prevent the development of renal diseases.

Terminal schwann cell distribution at the neuromuscular junction of the dystrophin-deficient MDX mice

The murine model of muscular dystrophy, the mdx mice, is widely used to study the pathogenesis of muscular dystrophies. These mice suffer an X-linked dystrophin deficiency and present cycles of muscle fiber degeneration-regeneration beginning at 21 days of age. At the present, we studied neuromuscular junction organization in the sternomastoid muscle of mdx mice, focusing on the distribution of terminal Schwann cells during early development and adults. Seven and 14 days after birth (n=200 endplates for each age), before the onset of muscle degeneration-regeneration, fluorescence confocal microscopy showed that there were no detectable differences in the pattern of Schwann cell distribution in the mdx compared to controls of the same age. Schwann cells had a diffuse pattern of distribution, covering the plaques of acetylcholine receptors. In adult mdx muscles, terminal Schwann cell processes filled the center of acetylcholine receptors islands, similar to nerve terminal distribution, at the majority of the junctions (n=200; 100%). Conversely, all of the adult control junctions (n=200) showed continuous processes of Schwann cells covering the continuous branches of acetylcholine receptors. These observations indicate that remodeling of the three components of the neuromuscular junction occurs only after the onset of the cycles of muscle fiber degeneration-regeneration, in the mdx mice.

Expression of human micro-dystrophin gene after retrovirus infection in mdx mice bone marrow-derived mesenchymal stem cells / 中国医学科学院学报

<p><b>OBJECTIVE</b>To construct the retroviral vector containing human micro-dystrophin gene and detect the expression of human micro-dystrophin in mdx mice bone marrow-derived mesenchymal stem cells (MSCs) after retrovirus infection.</p><p><b>METHODS</b>Retroviral vector for micro-dystrophin gene was constructed and transferred into the packing cell PA317 mediated by Lipofectamine 2000. The retroviral supernatant containing the target genes were subsequently used to infect mdx mice MSCs. Micro-dystrophin expression was examined by methods of immunofluorescence staining and reverse transcriptase-polymerase chain reaction.</p><p><b>RESULTS</b>Micro-dystrophin retroviral vector was successfully constructed and transferred into PA317 cells, and 48 h after infection with the recombinant retrovirus in mdx mice MSCs, 319 bp fragment could be detected by electrophoresis in the RT-PCR products. The red particles could be detected in some infected mdx mice MSCs with immunofluorescence staining. CONCLUSION mdx mice MSCs infected with retrovirus containing micro-dystrophin gene can express micro-dystrophin protein.</p>

Distrofia muscular nutricional em ovinos na Paraíba / Nutritional muscular dystrophy in sheep in Paraíba

Descreve-se um surto de distrofia muscular nutricional em ovinos no semi-árido Nordestino. Foram afetados animais de 3-4 meses de idade, da raça Dorper, pesando 30-40 kg. Os animais eram alimentados, à vontade, com leite, ração balanceada, capim Tifton e sal mineral. Dos 70 animais Dorper, 6 adoeceram e morreram em um período de 48 horas. Apresentaram temperatura, entre 40 e 41ºC, incoordenação com posterior paralisia e decúbito, depressão, prostração e diminuição dos reflexos pupilar e de ameaça, flacidez da língua e mandíbula, salivação, edema submandibular, dispnéia e aumento da freqüência cardíaca. A morte ocorreu após curso clínico de 6- 12 horas. Na necropsia de 3 animais, os músculos esqueléticos estavam de coloração pálida, o fígado estava aumentado de volume e de coloração amarelada, os gânglios parotídeos, submandibulares, retrofaríngeos, prescapulares e mediastínicos estavam aumentados de volume e avermelhados e os pulmões apresentavam áreas vermelhas. Na histologia havia necrose segmentar de todos os músculos examinados e congestão dos gânglios linfáticos e pulmão. Posteriormente mais três animais adoeceram, sendo tratado com oxitetraciclina e complexo vitamínico A,D e E. Desses 3 animais, 2 morreram e um sobreviveu. Na mesma fazenda havia e não adoeceram 20 ovinos da raça Santa Inês, da mesma idade que os animais afetados, que recebiam a mesma alimentação exceto o leite, e 900 ovinos de outras idades. A superalimentação em animais com rápido crescimento e o estresse causado pela restrição de água durantes 2 dias, para aumentar o consumo de leite, parecem ter sido fatores predisponentes para a ocorrência da doença. É possível, também, que algum dos minerais suplementados tenha antagonizado o Se presente na alimentação.

Impaired regeneration of dystrophin-deficient muscle fibers is caused by exhaustion of myogenic cells

Duchenne muscular dystrophy is one of the most devastating myopathies. Muscle fibers undergo necrosis and lose their ability to regenerate, and this may be related to increased interstitial fibrosis or the exhaustion of satellite cells. In this study, we used mdx mice, an animal model of Duchenne muscular dystrophy, to assess whether muscle fibers lose their ability to regenerate after repeated cycles of degeneration-regeneration and to establish the role of interstitial fibrosis or exhaustion of satellite cells in this process. Repeated degenerative-regenerative cycles were induced by the injection of bupivacaine (33 mg/kg), a myotoxic agent. Bupivacaine was injected weekly into the right tibialis anterior muscle of male, 8-week-old mdx (N = 20) and C57Bl/10 (control, N = 10) mice for 20 and 50 weeks. Three weeks after the last injection, the mice were killed and the proportion of regenerated fibers was counted and reported as a fibrosis index. Twenty weekly bupivacaine injections did not change the ability of mdx muscle to regenerate. However, after 50 weekly bupivacaine injections, there was a significant decrease in the regenerative response. There was no correlation between the inability to regenerate and the increase in interstitial fibrosis. These results show that after prolonged repeated cycles of degeneration-regeneration, mdx muscle loses its ability to regenerate because of the exhaustion of satellite cells, rather than because of an increase in interstitial fibrosis. This finding may be relevant to cell and gene therapy in the treatment of Duchenne muscular dystrophy

Altered deposition of extracellular matrix components in the skeletal muscle and lymph node of the MDX dystrophic mouse

1. MDX mice derived from a colony of C57BL/10ScSn mice develop an X-linked recessive muscular dystrophy, thus providing an adequate to study the pathogenesis of muscular dystrophy. 2. Skeletal myofibers of MDX mutant mice were heterogenous, with disorganization of myofilaments and the absence of immunolabelling for dystrophin with monoclonal antibody DY4/6D3. 3. Marked deposition of reticulin, collagenic fiber (types I, IV) and laminin (LN) were consistently present mostly around lesioned and necrotic myofibers associated eith an intense inflammatory reaction, whereas strong immunolabelling for TIII-C, TIV-C and FN was often associated with regenerated fibers. 4. During the onset (3 weeks of postnatal life) of disease and height of myonecrosis (5-6 weeks of postnatal life), popliteal lymph nodes showed dense argyrophilic meshwork, intense immunolabeling for collagens types I and IV, FN, LN and enlargement of the hili which were packed with mononuclear cells. Such alterations, albeit less intense, were still observed in MDX mice with 20 weeks of postnatal life. 5 The results support the view that ECM components might be influencing the migration of inflammatory cells and the process of myonecrosis in the skeletal muscle of MDX dystrophic mice