RESUMO
Heart failure (HF) is characterized by a reduced tolerance to exercise due to early fatigue and dyspnea; this may be due in part to skeletal muscle myopathy with a shift from slow to fast fibers and loss of muscle mass. Muscle wasting does not occur similarly in all types of muscle fiber, thus we tested the hypothesis that HF induces skeletal muscle atrophy in a fiber type-specific manner altering the expression of atrogin-1 and MuRF1 in a fast muscle of rats with monocrotaline-induced heart failure. We studied extensor digitorum longus (EDL) muscle from both HF and control Wistar rats. Atrogin-1 and MuRF1 mRNA content were determined using Real-Time RT-qPCR while muscle fiber cross-sectional area (CSA) from sections stained histochemically for myofibrillar ATPase were used as an index of type-specific fiber atrophy. The measurement of gene expression by RT-qPCR revealed that EDL muscle mRNA expression of MuRF1 and atrogin-1 was significantly increased in the HF group. Muscle fiber type IIB CSA decreased in the HF group compared to the CT group; there was no significant difference in muscle fiber types I and IIA/D CSA between the HF and CT groups. In conclusion, we showed that HF induces fiber type IIB specific atrophy, up-regulating atrogin-1 and MuRF1 mRNA expression in EDL muscle of monocrotaline treated rats.
Assuntos
Regulação da Expressão Gênica , Insuficiência Cardíaca/genética , Fibras Musculares Esqueléticas/metabolismo , Fibras Musculares Esqueléticas/patologia , Proteínas Musculares/genética , Atrofia Muscular/genética , Proteínas Ligases SKP Culina F-Box/genética , Ubiquitina-Proteína Ligases/genética , Animais , Insuficiência Cardíaca/patologia , Masculino , Monocrotalina , Proteínas Musculares/metabolismo , Atrofia Muscular/patologia , Especificidade de Órgãos/genética , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteínas Ligases SKP Culina F-Box/metabolismo , Proteínas com Motivo Tripartido , Ubiquitina-Proteína Ligases/metabolismoRESUMO
Here, we evaluated collagen distribution and matrix metalloproteinases (MMPs) MMP-2 and MMP-9 activities in skeletal muscle of pacu (Piaractus mesopotamicus) during juvenile and adult growth phases. Muscle samples from juvenile and adult fishes were processed by histochemistry for collagen system fibers and for gelatin-zymography for MMP-2 and MMP-9 activities analysis. Picrosirius staining revealed a myosept, endomysium, and perimysium-like structures in both growth phases and muscle types, with increased areas of collagen fibers in adults, mainly in red muscle. Reticulin staining showed that reticular fibers in the endomysium-like structure were thinner and discontinuous in the red muscle fibers. The zymography revealed clear bands of the pro- MMP-9, active- MMP-9, intermediate- MMP-2, and active- MMP-2 forms in red and white muscle in both growth phases. MMP-2 activity was more intense in juvenile than adult muscle fibers. Comparing the red and white muscle types, MMP-2 activity was significantly higher in red muscle in adult phase only. The activity of MMP-9 forms was similar in juvenile red and white muscles and in the adult red muscle, without any activity in adult white muscle. In conclusion, our results show that, in pacu, the higher activities of MMP-2 and -9 are associated with the rapid muscle growth in juvenile age and in adult fish, these activities are related with a different red and white muscle physiology. This study may contribute to the understanding muscle growth mechanisms and may also contribute to analyse red and the white muscle parameters of firmness and softness, respectively, of the commercial product.
Assuntos
Colágeno/metabolismo , Peixes/crescimento & desenvolvimento , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Músculo Esquelético/enzimologia , Animais , HistocitoquímicaRESUMO
Epífitas são plantas que se desenvolvem sobre outras plantas sem parasitá-las. Pouco se conhece sobre este grupo de plantas na região, tornando-se importantes estudos deste caráter. Desta forma o objetivo desse trabalho foi caracterizar a composição florística do componente epifítico vascular das formações florestais ocorrentes no local. A área alvo do estudo situa-se na Fazenda Noiva da Colina, Município de Borebi, Estado de São Paulo. O local estudado com aproximadamente 120.000m², possui Floresta Estacional Semidecidual, Mata de Galeria e Floresta Latifoliada Higrófila. Foram identificadas 27 espécies, pertencentes a 18 gêneros e 8 famílias, sendo que as famílias com maior riqueza de espécies foram Bromeliaceae e Orchidaceae, juntas representando pouco mais da metade dos taxa encontrados. Tillandsia com cinco espécies foi o gênero mais abundante e relativo à categoria ecológica, as holoepífitas características foram as mais representadas na sinúsia estudada.
Epiphytes are plants that grow on other plants without sponging them. Little her on this group of plants knows in the Area, becoming important studies of this character. This way the objective of that work was to characterize the composition florístic of the component vascular epiphyte of the formations forest ocorrents in the place. The area white of the study locates in Finance it Becomes engaged of the Hill, Municipal district of Borebi, State of São Paulo. The place studied with approximately 120.000m², it possesses Seasonal Forest Semidecidual, Forest of Gallery and Floresta Latifoliada Higrófila. They were identified 27 species, belonging to 18 goods and 8 families, and the families with larger wealth of species were Bromeliaceae and Orchidaceae, committees representing little more of the half of the rate found. Tillandsia with 5 species was the most abundant and relative gender the ecological category, the characteristic holoephytes were the more represented in the studied sinúsia.