Ringraziamo Bob Nowak (Andor Technology) per assistenza e consulenza tecnica. SA-S. è sostenuto da una borsa di studio Heisenberg della Deutsche Forschungsgemeinschaft (DFG). Questo lavoro è stato sostenuto da DFG concessione SE2016/7-1.

1. Etichettatura singole cellule Iniettare unicellulari embrioni allo stadio con un plasmide codificante GFP o qualsiasi proteina di fusione GFP sotto il controllo di un promotore di β-actina. Durante lo sviluppo, GFP è quindi espresso in modo mosaico. Qui, abbiamo usato il costrutto transgenico Tg [β-actina: α-actinina-GFP], che pone l&#39;α-actinina-proteina di fusione GFP sotto il controllo del promotore di β-actina. 2. Embrione Embedding <ol class="lalpha"><li> Raccogliere embrioni di zebrafish e mantenere, in condizioni normali, fino al 28 HPF (stadiazione secondo a 12). </li><li> Embrioni Dechorionate allo stereomicroscopio con una pinza (Dumont # 5). </li><li> Preparare un vetrino da microscopio con un anello di vaselina. </li><li> Preparare un 1% a basso punto di fusione agarosio / 10% soluzione tricaine con mezzo E3: bollire 100 mg di agarosio in 10 ml di soluzione E3 ad ottenere un liquido omogeneo e soluzione di agarosio, aliquota e memorizzareinutilizzato soluzione di agarosio a -20 ° C per un ulteriore uso. Per l&#39;uso immediato, lasciare che la soluzione bollita raffreddare e mantenere al massimo. 39 ° C. Aggiungi soluzione madre tricaine per ottenere una concentrazione finale del 10% tricaine. Sia tricaine e agarosio sono necessari per impedire movimenti embrionali. </li><li> Incorporamento di un singolo embrione in 1% di agarosio a basso punto di fusione / 10% tricaine / E3 media all&#39;interno dell&#39;anello vaselina, con l&#39;embrione, che naturalmente sul lato, delicatamente coprire con un coprioggetto solo per mantenere l&#39;embrione in atto e per evitare un convesso superficie che avrebbe rotto la luce. Idealmente, il tessuto muscolare embrionale che saranno destinati dovrebbe toccare il coprioggetto. </li></ol> 3. Embryo Laser-ferimento <ol class="lalpha"><li> Preparare il laser Micropoint e il microscopio: <ol class="lroman"><li> Si prega di fare riferimento al manuale Micropoint laser per le istruzioni dettagliate su come impostare e utilizzare il laser in combinazione con il microscopio. </li><li> Selezionare la correttacolorante per la generazione di un fascio laser 435 nm di lunghezza d&#39;onda. </li><li> Regolare la potenza del laser utilizzando il cursore attenuazione. La potenza del laser dovrebbe essere abbastanza forte per rompere una superficie di vetro con un singolo impulso (es. fuoco sul vetrino del campione per testare questa). Questa è la potenza necessaria per l&#39;ablazione laser cella. </li></ol></li><li> Concentrarsi sulla regione o cella di interesse utilizzando il reticolo installato nel oculare del microscopio. Utilizzare un obiettivo 20x (40x permetterà danni più precisa, ma spesso la distanza di lavoro non è sufficiente per questo obiettivo). </li></ol> Nota 1: Il laser non solo danneggiare le cellule all&#39;interno del piano di fuoco, ma anche celle sopra e sotto che sono entro il raggio laser. Assicurarsi prima dell&#39;esperimento che il laser sia impostato in modo ottimale e regolata per una massima attenzione ai asse z. È preferibile determinare la profondità del danno laser prima di eseguire l&#39;esperimento per sapere quale cellas esattamente saranno feriti. <ol class="lalpha" start="3"><li> Impostare la luce necessaria per visualizzare l&#39;esperimento: campo chiaro per l&#39;uso normale, il targeting o la fluorescenza se una cella fluorescente marcato. </li><li> Inviare un impulso di luce laser per la regione mirati, o più impulsi, a seconda del grado desiderato di lesioni. </li></ol> 4. Analisi della Ferita e recupero <ol class="lalpha"><li> Se desiderato, la procedura di lesioni laser possono essere registrati vivo (ad esempio utilizzando l&#39;opzione di acquisizione flusso del software Metamorph). 6 </li><li> Subito dopo il ferimento, l&#39;embrione deve essere rimosso con delicatezza dal agarosio con una pinza e rimesso in acqua uovo per il recupero. </li></ol> Nota 2: l&#39;attività muscolare (nuoto e spasmi), è particolarmente importante per il recupero del muscolo scheletrico. Poiché l&#39;embrione non può muoversi a causa dell&#39;esposizione tricaine e l&#39;incorporamento rigida agarosio, non è RACCOMAnded mantenere gli embrioni tra vetrino e coprioggetto per troppo tempo. <ol class="lalpha" start="3"><li> Dopo il recupero, l&#39;embrione può essere fissato e analizzati come desiderato dalla luce, microscopia a fluorescenza o confocale come indicato. </li></ol>

<ol>
	<li>Charge, S. B., Rudnicki, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellular+and+molecular+regulation+of+muscle+regeneration.">Cellular and molecular regulation of muscle regeneration.</a> Physiol. Rev. 84, 209-238 (2004).</li><li>Steffen, L. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+zebrafish+runzel+muscular+dystrophy+is+linked+to+the+titin+gene.">The zebrafish runzel muscular dystrophy is linked to the titin gene.</a> Dev. Biol. 309, 180-192 (2007).</li><li>Bassett, D., Currie, P. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+a+zebrafish+model+of+muscular+dystrophy.">Identification of a zebrafish model of muscular dystrophy.</a> Clin. Exp. Pharmacol. Physiol. 31, 537-540 (2004).</li><li>Kawahara, G., Serafini, P. R., Myers, J. A., Alexander, M. S., Kunkel, L. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+zebrafish+dysferlin+by+morpholino+knockdown.">Characterization of zebrafish dysferlin by morpholino knockdown.</a> Biochem. Biophys. Res. Commun. 413, 358-363 (2011).</li><li>Behra, M., Etard, C., Cousin, X., Str&#228;hle, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+use+of+zebrafish+mutants+to+identify+secondary+target+effects+of+acetylcholine+esterase+inhibitors.">The use of zebrafish mutants to identify secondary target effects of acetylcholine esterase inhibitors.</a> Toxicol. Sci. 77, 325-333 (2004).</li><li>Otten, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Xirp+proteins+mark+injured+skeletal+muscle+in+zebrafish.">Xirp proteins mark injured skeletal muscle in zebrafish.</a> PLoS One. 7, e31041 (2012).</li><li>Roostalu, U., Str&#228;hle, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+imaging+of+molecular+interactions+at+damaged+sarcolemma.">In vivo imaging of molecular interactions at damaged sarcolemma.</a> Dev. Cell. 22, 515-529 (2012).</li><li>Stickney, H. L., Barresi, M. J., Devoto, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Somite+development+in+zebrafish.">Somite development in zebrafish.</a> Dev. Dyn. 219, 287-303 (2000).</li><li>Stellabotte, F., Dobbs-McAuliffe, B., Fernandez, D. A., Feng, X., Devoto, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamic+somite+cell+rearrangements+lead+to+distinct+waves+of+myotome+growth.">Dynamic somite cell rearrangements lead to distinct waves of myotome growth.</a> Development. 134, 1253-1257 (2007).</li><li>Choi, W. Y., Poss, K. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+regeneration.">Cardiac regeneration.</a> Curr. Top. Dev. Biol. 100, 319-344 (2012).</li><li>Stewart, S., Stankunas, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Limited+dedifferentiation+provides+replacement+tissue+during+zebrafish+fin+regeneration.">Limited dedifferentiation provides replacement tissue during zebrafish fin regeneration.</a> Dev. Biol. 365, 339-349 (2012).</li><li>Kimmel, C. B., Ballard, W. W., Kimmel, S. R., Ullmann, B., Schilling, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stages+of+embryonic+development+of+the+zebrafish.">Stages of embryonic development of the zebrafish.</a> Dev. Dyn. , 203-253 (1995).</li></ol>

Nessun conflitto di interessi dichiarati.

Laser-mediata lesione è un metodo efficace per infliggere ferite della dimensione desiderata da ablazione cellule per studiare la rigenerazione in condizioni controllate in zebrafish. In particolare, le cellule possono essere mirati proprio (Figura 2) e sia l&#39;area ferita e tempi può essere controllato. Successivamente, il sito di lesione e processi di rigenerazione sono facilmente controllati, registrati (Figura 3) e analizzati (Figura 1). Tuttavia, anche se il la...

<table border="1"><tbody><tr><td> Riscaldamento del blocco </td><td></td><td></td><td></td></tr><tr><td> Coppia pinze # 5 </td><td> Dumont </td><td></td><td></td></tr><tr><td> Diapositiva su vetro </td><td> Menzel </td><td></td><td> 76 x 26 mm </td></tr><tr><td> Coprioggetto </td><td> Roth </td><td></td><td> 50 x 24 mm N ° 1 </td></tr><tr><td> Vaselina </td><td></td><td></td><td></td></tr><tr><td> Stereomicroscopio </td><td> Leica </td><td></td><td> MZFLIII </td></tr><tr><td> Micropoint laser </td><td> Andor Tecnologia </td><td></td><td></td></tr><tr><td> Microscopio a fluorescenza </td><td> Zeiss </td><td></td><td> Axioplan II </td></tr><tr><td> Metamorph software </td><td> Molecular Devices </td><td></td><td></td></tr><tr><td></td><td></td><td></td><td> Reagenti <ul><li> Basso punto di fusione agarosio (# 50081,Lonza) </li><li> Tricaine Soluzione madre: 400 mg Tricaine (# A-5040, Sigma-Aldrich) / 100 ml di dH 2 O pH 9,0 </li><li> Media E3 (5 mM NaCl, 0,17 mM KCl, 0,33 mM CaCl 2, 0,33 mM MgSO4) </li></ul></td></tr></tbody></table>

laser-inflicted injury of zebrafish embryonic skeletal muscle

Diversi approcci sperimentali sono stati utilizzati nel topo per indurre infortunio muscolare, con l&#39;obiettivo di studiare la rigenerazione muscolare, compresi gli apporti myotoxin (bupivacaina, cardiotossina o notexin), trapianti muscolari (denervazione-devascolarizzazione rigenerazione indotta), esercizio fisico intenso, ma anche modelli murini distrofia muscolare come ad esempio il topo mdx (per una rassegna di questi approcci vedi 1). In zebrafish, approcci genetici includono mutanti che presentano fenotipi distrofia muscolare (come runzel 2 o sapje 3) e antisenso Morpholinos oligonucleotide che bloccano l&#39;espressione di geni associati alla distrofia 4. Inoltre, approcci chimici sono possibili, per esempio con Galanthamine, un composto chimico inibente acetilcolinesterasi, ottenendo in tal modo ipercontrazione, che finisce per distrofia muscolare 5. Approcci tuttavia, genetici e farmacologici generally colpire tutti i muscoli all&#39;interno di un individuo, mentre l&#39;entità delle ferite inferte fisicamente sono più facilmente controllabili spazialmente e temporalmente 1. Localizzata lesioni consente la valutazione del muscolo controlaterale come controllo interno. Infatti, abbiamo recentemente utilizzato ablazione laser-mediata delle cellule per studiare la rigenerazione del muscolo scheletrico nel zebrafish 6, mentre un altro gruppo ha recentemente riportato l&#39;uso di un laser a due fotoni (822 nm) per danneggiare molto localmente la membrana plasmatica di singoli muscoli zebrafish embrionale celle 7. Qui, si riporta un metodo per utilizzare il laser Micropoint (Andor Technology) per lesioni cellula muscolare scheletrica in zebrafish. Il laser Micropoint è un laser ad alta energia che è adatto per l&#39;ablazione cellula bersaglio alla lunghezza d&#39;onda di 435 nm. Il laser viene collegato ad un microscopio (nel nostro setup, un microscopio ottico Zeiss da) in modo tale che il microscopio può essere utilizzato al tempo stesso fo focalizzare la luce laser sul campione e per visualizzare gli effetti della ferita (campo chiaro o fluorescenza). I parametri per controllare gli impulsi laser comprendono lunghezza d&#39;onda, intensità e numero di impulsi. Grazie alla sua trasparenza ed esterna sviluppo embrionale, l&#39;embrione di zebrafish è altamente suscettibile sia indotta da laser pregiudizio e per lo studio del successivo recupero. Tra 1 e 2 giorni dopo la fecondazione, somitic cellule muscolari scheletriche progressivamente maturano da anteriore a posteriore a causa della progressione della somitogenesis dal tronco alla coda 8, 9. In queste fasi, embrioni spontaneamente twitch e avviare il nuoto. Il pesce zebra è stata recentemente riconosciuta come un importante organismo modello vertebrato per lo studio della rigenerazione dei tessuti, come molti tipi di tessuti (cardiache, neuronale, vascolare ecc) possono essere rigenerati dopo lesione nell&#39;adulto zebrafish 10, 11.

Lesioni laser-mediata è stata eseguita su immobilizzati 1 giorno di età embrioni. Come mostrato in figura 1, un paio di impulsi laser può generare una ferita piccola, facilmente riconoscibili dai danneggiati, arrotolati, Actina ricchi miofibrille che sono normalmente tese tra i confini somite. Un più alto numero di impulsi laser sarà comunque comportare un blocco somite massicciamente danneggiato, dove vengono distrutti maggior miofibrille. Tuttavia, si può osservare che letteralmente &quot;il tem...

Watch this Scientific Journal Video about Laser-inflicted Injury of Zebrafish Embryonic Skeletal Muscle at JoVE.com

Laser-inflicted Injury of Zebrafish Embryonic Skeletal Muscle

Il metodo qui presentato comprende il pregiudizio preciso di embrioni di zebrafish in diretta con alta energia impulsi laser e la successiva analisi di tali lesioni e il loro recupero con il tempo. Mostriamo anche come geneticamente etichettati singoli o gruppi di cellule muscolari scheletriche possono essere monitorati durante e dopo un danno luce laser indotto.

Laser-lesioni del muscolo scheletrico embrionale Zebrafish

Various experimental approaches have been used in mouse to induce muscle injury with the aim to study muscle regeneration, including myotoxin injections ...

laser-inflicted-injury-of-zebrafish-embryonic-skeletal-muscle

Research

JoVE Journal

Biology

10.4K Views.  Max Delbrück Center for Molecular Medicine. Il metodo qui presentato comprende il pregiudizio preciso di embrioni di zebrafish in diretta con alta energia impulsi laser e la successiva analisi di tali lesioni e il loro recupero con il tempo. Mostriamo anche come geneticamente etichettati singoli o gruppi di cellule muscolari scheletriche possono essere monitorati durante e dopo un danno luce laser indotto.

Video: Laser-inflicted Injury of Zebrafish Embryonic Skeletal Muscle

Adult and Embryonic Skeletal Muscle Microexplant Culture and Isolation of Skeletal Muscle Stem Cells

Cultured embryonic and adult skeletal muscle cells have a number of different uses. The micro-dissected explants technique described in this chapter is a robust and reliable method for isolating relatively large numbers of proliferative skeletal muscle cells from juvenile, adult or embryonic muscles as a source of skeletal muscle stem cells. The authors have used micro-dissected explant cultures to analyse the growth characteristics of skeletal muscle cells in wild-type and dystrophic muscles. Each of the components of tissue growth, namely cell survival, proliferation, senescence and differentiation can be analysed separately using the methods described here. The net effect of all components of growth can be established by means of measuring explant outgrowth rates. The micro-explant method can be used to establish primary cultures from a wide range of different muscle types and ages and, as described here, has been adapted by the authors to enable the isolation of embryonic skeletal muscle precursors.
Uniquely, micro-explant cultures have been used to derive clonal (single cell origin) skeletal muscle stem cell (SMSc) lines which can be expanded and used for in vivo transplantation. In vivo transplanted SMSc behave as functional, tissue-specific, satellite cells which contribute to skeletal muscle fibre regeneration but which are also retained (in the satellite cell niche) as a small pool of undifferentiated stem cells which can be re-isolated into culture using the micro-explant method.

The micro-dissected explants technique is a robust and reliable method for isolating proliferative skeletal muscle cells from juvenile, adult or embryonic muscles as a source of skeletal muscle stem cells. Uniquely, these cells have been clonally derived to produce skeletal muscle stem cell lines used for in vivo transplantation.

Adulte e embrionali muscolo scheletrico Microexplant Cultura e isolamento di cellule staminali del muscolo scheletrico

Cultured embryonic and adult skeletal muscle cells have a number of different uses. The micro-dissected explants technique described in this chapter is a ...

Ricerca

Biologia

Mitochondrial Isolation from Skeletal Muscle

Mitochondria are organelles controlling the life and death of the cell. They participate in key metabolic reactions, synthesize most of the ATP, and regulate a number of signaling cascades2,3. Past and current researchers have isolated mitochondria from rat and mice tissues such as liver, brain and heart4,5. In recent years, many researchers have focused on studying mitochondrial function from skeletal muscles.
Here, we describe a method that we have used successfully for the isolation of mitochondria from skeletal muscles 6. Our procedure requires that all buffers and reagents are made fresh and need about 250-500 mg of skeletal muscle. We studied mitochondria isolated from rat and mouse gastrocnemius and diaphragm, and rat extraocular muscles. Mitochondrial protein concentration is measured with the Bradford assay. It is important that mitochondrial samples be kept ice-cold during preparation and that functional studies be performed within a relatively short time (~1 hr). Mitochondrial respiration is measured using polarography with a Clark-type electrode (Oxygraph system) at 37&deg;C7. Calibration of the oxygen electrode is a key step in this protocol and it must be performed daily. Isolated mitochondria (150 &mu;g) are added to 0.5 ml of experimental buffer (EB). State 2 respiration starts with addition of glutamate (5mM) and malate (2.5 mM). Then, adenosine diphosphate (ADP) (150 &mu;M) is added to start state 3. Oligomycin (1 &mu;M), an ATPase synthase blocker, is used to estimate state 4. Lastly, carbonyl cyanide p-[trifluoromethoxy]-phenyl-hydrazone (FCCP, 0.2 &mu;M) is added to measurestate 5, or uncoupled respiration 6. The respiratory control ratio (RCR), the ratio of state 3 to state 4, is calculated after each experiment. An RCR &ge;4 is considered as evidence of a viable mitochondria preparation.
In summary, we present a method for the isolation of viable mitochondria from skeletal muscles that can be used in biochemical (e.g., enzyme activity, immunodetection, proteomics) and functional studies (mitochondrial respiration).

This protocol describes a procedure to study the respiration of mitochondria isolated from skeletal muscles. This method was adapted from Scorrano et al. (2007). The mitochondrial isolation procedure requires about 2 hours. The mitochondrial respiration can be completed in about 1 hour.

Isolamento dei mitocondri dal muscolo scheletrico

Mitochondria are organelles controlling the life and death of the cell. They participate in key metabolic reactions, synthesize most of the ATP, and ...

Purification of Progenitors from Skeletal Muscle

Skeletal muscle contains multiple progenitor populations of distinct embryonic origins and developmental potential. Myogenic progenitors, usually residing in a "satellite cell position" between the myofiber plasma membrane and the laminin-rich basement membrane that ensheaths it, are self-renewing cells that are solely committed to the myogenic lineage1,2. We have recently described a second class of vessel associated progenitors that can generate myofibroblasts and white adipocytes, which responds to damage by efficiently entering proliferation and provides trophic support to myogenic cells during tissue regeneration3,4. One of the most trusted assays to determine the developmental and regenerative potential of a given cell population relies on their isolation and transplantation5-7. To this end we have optimized protocols for their purification by flow cytometry from enzymatically dissociated muscle, which we will outline in this article. The populations obtained using this method will contain either myogenic or fibro/adipogenic colony forming cells: no other cell types are capable of expanding in vitro or surviving in vivo delivery. However, when these populations are used immediately after the sort for molecular analysis (e.g qRT-PCR) one must keep in mind that the freshly sorted subsets may contain other contaminant cells that lack the ability of forming colonies or engrafting recipients.

Method for the enzymatic dissociation, surface labeling and purification by flow cytometry of fibro/adipogenic and myogenic progenitors from murine skeletal muscle.

Purificazione di progenitori dal muscolo scheletrico

Skeletal muscle contains multiple progenitor populations of distinct embryonic origins and developmental potential. Myogenic progenitors, usually residing ...

Analysis of Embryonic and Larval Zebrafish Skeletal Myofibers from Dissociated Preparations

The zebrafish has proven to be a valuable model system for exploring skeletal muscle function and for studying human muscle diseases. Despite the many advantages offered by in vivo analysis of skeletal muscle in the zebrafish, visualizing the complex and finely structured protein milieu responsible for muscle function, especially in whole embryos, can be problematic. This hindrance stems from the small size of zebrafish skeletal muscle (60 &mu;m) and the even smaller size of the sarcomere. Here we describe and demonstrate a simple and rapid method for isolating skeletal myofibers from zebrafish embryos and larvae. We also include protocols that illustrate post preparation techniques useful for analyzing muscle structure and function. Specifically, we detail the subsequent immunocytochemical localization of skeletal muscle proteins and the qualitative analysis of stimulated calcium release via live cell calcium imaging. Overall, this video article provides a straight-forward and efficient method for the isolation and characterization of zebrafish skeletal myofibers, a technique which provides a conduit for myriad subsequent studies of muscle structure and function.

Zebrafish are an emerging system for modeling human disorders of the skeletal muscle. We describe a fast and efficient method to isolate skeletal muscle myofibers from embryonic and larval zebrafish. This method yields a high-density myofiber preparation suitable for study of single skeletal muscle fiber morphology, protein subcellular localization, and muscle physiology.

Analisi delle embrionali e larvali Zebrafish scheletriche miofibre da Preparazioni dissociata

The zebrafish has  proven to be a valuable model system for exploring skeletal muscle function and  for studying human muscle diseases. Despite  the many ...

Analysis of Skeletal Muscle Defects in Larval Zebrafish by Birefringence and Touch-evoke Escape Response Assays

Zebrafish (Danio rerio) have become a particularly effective tool for modeling human diseases affecting skeletal muscle, including muscular dystrophies1-3, congenital myopathies4,5, and disruptions in sarcomeric assembly6,7, due to high genomic and structural conservation with mammals8. Muscular disorganization and locomotive impairment can be quickly assessed in the zebrafish over the first few days post-fertilization. Two assays to help characterize skeletal muscle defects in zebrafish are birefringence (structural) and touch-evoked escape response (behavioral).
Birefringence is a physical property in which light is rotated as it passes through ordered matter, such as the pseudo-crystalline array of muscle sarcomeres9. It is a simple, noninvasive approach to assess muscle integrity in translucent zebrafish larvae early in development. Wild-type zebrafish with highly organized skeletal muscle appear very bright amidst a dark background when visualized between two polarized light filters, whereas muscle mutants have birefringence patterns specific to the primary muscular disorder they model. Zebrafish modeling muscular dystrophies, diseases characterized by myofiber degeneration followed by repeated rounds of regeneration, exhibit degenerative dark patches in skeletal muscle under polarized light. Nondystrophic myopathies are not associated with necrosis or regenerative changes, but result in disorganized myofibers and skeletal muscle weakness. Myopathic zebrafish typically show an overall reduction in birefringence, reflecting the disorganization of sarcomeres.
The touch-evoked escape assay involves observing an embryo&#39;s swimming behavior in response to tactile stimulation10-12. In comparison to wild-type larvae, mutant larvae frequently display a weak escape contraction, followed by slow swimming or other type of impaired motion that fails to propel the larvae more than a short distance12. The advantage of these assays is that disease progression in the same fish type can be monitored in vivo for several days, and that large numbers of fish can be analyzed in a short time relative to higher vertebrates.

The zebrafish is now an established and powerful tool for modeling muscular dystrophies, congenital myopathies, and related neuromuscular diseases. Birefringence and touch-evoked escape behavior are two common noninvasive assays used to determine the degree of muscular disorganization and locomotive impairment of zebrafish embryos during early development.

Analisi dei difetti muscolo scheletrico larvale Zebrafish da Birifrangenza e Touch-evocare Fuga risposta Saggi

Zebrafish (Danio rerio) have become a particularly effective tool for modeling human diseases affecting skeletal muscle, including muscular ...

Nephrotoxin Microinjection in Zebrafish to Model Acute Kidney Injury

The kidneys are susceptible to harm from exposure to chemicals they filter from the bloodstream. This can lead to organ injury associated with a rapid decline in renal function and development of the clinical syndrome known as acute kidney injury (AKI). Pharmacological agents used to treat medical circumstances ranging from bacterial infection to cancer, when administered individually or in combination with other drugs, can initiate AKI. Zebrafish are a useful animal model to study the chemical effects on renal function in vivo, as they form an embryonic kidney comprised of nephron functional units that are conserved with higher vertebrates, including humans. Further, zebrafish can be utilized to perform genetic and chemical screens, which provide opportunities to elucidate the cellular and molecular facets of AKI and develop therapeutic strategies such as the identification of nephroprotective molecules. Here, we demonstrate how microinjection into the zebrafish embryo can be utilized as a paradigm for nephrotoxin studies.

Renal injuries incurred from nephrotoxins, which include drugs ranging from antibiotics to chemotherapeutics, can result in complex disorders whose pathogenesis remains incompletely understood. This protocol demonstrates how zebrafish can be used for disease modeling of these conditions, which can be applied to the identification of renoprotective measures.

Nefrotossina microiniezione in Zebrafish per creare un modello danno renale acuto

The kidneys are susceptible to harm from exposure to chemicals they filter from the bloodstream. This can lead to organ injury associated with a rapid ...

Electroporation of Plasmid DNA into Mouse Skeletal Muscle

Transient gene expression modulation in murine skeletal muscle by plasmid electroporation is a useful tool for assessing normal and pathological physiology. Overexpression or knockdown of target genes enables investigators to manipulate individual molecular events and, thus, better understand the mechanisms that impact muscle mass, muscle metabolism, and contractility. In addition, electroporation of DNA plasmids that encode fluorescent tags allows investigators to measure changes in subcellular localization of proteins in skeletal muscle in vivo. A key functional assessment of skeletal muscle includes the measurement of muscle contractility. In this protocol, we demonstrate that whole muscle contractility studies are still possible after plasmid DNA injection, electroporation, and gene expression modulation. The goal of this instructional procedure is to demonstrate the step-by-step method of DNA plasmid electroporation into mouse skeletal muscle to facilitate uptake and expression in the myofibers of the tibialis anterior and extensor digitorum longus muscles, as well as to demonstrate that skeletal muscle contractility is not compromised by injection and electroporation.

Electroporation of plasmid DNA into skeletal muscle is a viable method to modulate gene expression without compromising muscle contractility in mice.

Elettroporazione del DNA plasmidico nel muscolo scheletrico del topo

Transient gene expression modulation in murine skeletal muscle by plasmid electroporation is a useful tool for assessing normal and pathological ...

High-Resolution Fluoro-Respirometry of Equine Skeletal Muscle

Mitochondrial function-oxidative phosphorylation and the generation of reactive oxygen species-is critical in both health and disease. Thus, measuring mitochondrial function is fundamental in biomedical research. Skeletal muscle is a robust source of mitochondria, particularly in animals with a very high aerobic capacity, such as horses, making them ideal subjects for studying mitochondrial physiology. This article demonstrates the use of high-resolution respirometry with concurrent fluorometry, with freshly harvested skeletal muscle mitochondria, to quantify the capacity to oxidize substrates under different mitochondrial states and determine the relative capacities of distinct elements of mitochondrial respiration. Tetramethylrhodamine methylester is used to demonstrate the production of mitochondrial membrane potential resulting from substrate oxidation, including calculation of the relative efficiency of the mitochondria by calculating the relative membrane potential generated per unit of concurrent oxygen flux. The conversion of ADP to ATP results in a change in the concentration of magnesium in the reaction chamber, due to differing affinities of the adenylates for magnesium. Therefore, magnesium green can be used to measure the rate of ATP synthesis, allowing the further calculation of the oxidative phosphorylation efficiency (ratio of phosphorylation to oxidation [P/O]). Finally, the use of Amplex UltraRed, which produces a fluorescent product (resorufin) when combined with hydrogen peroxide, allows the quantification of reactive oxygen species production during mitochondrial respiration, as well as the relationship between ROS production and concurrent respiration. These techniques allow the robust quantification of mitochondrial physiology under a variety of different simulated conditions, thus shedding light on the contribution of this critical cellular component to both health and disease.

Horses have an exceptional aerobic exercise capacity, making equine skeletal muscle an important tissue for both the study of equine exercise physiology as well as mammalian mitochondrial physiology. This article describes techniques for the comprehensive assessment of mitochondrial function in equine skeletal muscle.

Fluoro-respirometria ad alta risoluzione del muscolo scheletrico equino

Mitochondrial function-oxidative phosphorylation and the generation of reactive oxygen species-is critical in both health and disease. Thus, measuring ...

Quantificazione dell'infiltrazione adiposa del muscolo scheletrico mediante decellularizzazione

Decellularization-Based Quantification of Skeletal Muscle Fatty Infiltration

Fatty infiltration is the accumulation of adipocytes between myofibers in skeletal muscle and is a prominent feature of many myopathies, metabolic disorders, and dystrophies. Clinically in human populations, fatty infiltration is assessed using noninvasive methods, including computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound (US). Although some studies have used CT or MRI to quantify fatty infiltration in mouse muscle, costs and insufficient spatial resolution remain challenging. Other small animal methods utilize histology to visualize individual adipocytes; however, this methodology suffers from sampling bias in heterogeneous pathology. This protocol describes the methodology to qualitatively view and quantitatively measure fatty infiltration comprehensively throughout intact mouse muscle and at the level of individual adipocytes using decellularization. The protocol is not limited to specific muscles or specific species and can be extended to human biopsy. Additionally, gross qualitative and quantitative assessments can be made with standard laboratory equipment for little cost, making this procedure more accessible across research laboratories.

Autore in primo piano: Quantificazione basata sulla decellularizzazione dell'infiltrazione adiposa del muscolo scheletrico  

The present study describes decellularization-based methodologies for visualizing and quantifying intramuscular adipose tissue (IMAT) deposition through intact muscle volume, as well as quantifying metrics of individual adipocytes that comprise IMAT.